diff --git a/ChangeLog b/ChangeLog
index 53c62804..e9742c99 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2026-09-26 (12.34)
+	TEENSY: Add flash and SD card file system
+	WINDOWS: Remove __p__environ warning when building
+
 2026-04-28 (12.34)
 	COMMON: implement plugin_refresh_id for variable lifecycle handling
 	COMMON: fix bug with comma in string assigned as local #283
diff --git a/src/common/system.c b/src/common/system.c
index 16d32584..7ad9357d 100644
--- a/src/common/system.c
+++ b/src/common/system.c
@@ -23,8 +23,6 @@
 #include <dir.h>
 #endif
 
-extern char **environ;
-
 #define BUFSIZE 1024
 
 #if defined(_Win32)
@@ -126,6 +124,8 @@ int dev_run(const char *cmd, var_t *r, int wait) {
 }
 
 #else
+extern char **environ;
+
 int dev_run(const char *cmd, var_t *r, int wait) {
   int result = 1;
   if (r != NULL) {
diff --git a/src/platform/teensy/CMakeLists.txt b/src/platform/teensy/CMakeLists.txt
index 8304ea0a..aa259832 100644
--- a/src/platform/teensy/CMakeLists.txt
+++ b/src/platform/teensy/CMakeLists.txt
@@ -42,6 +42,7 @@ set(CMAKE_EXE_LINKER_FLAGS "-Os -Wl,--gc-sections,--relax ${SPECS} ${CPU_OPTIONS
 set(CMAKE_CXX_COMPILER arm-none-eabi-g++)
 set(CMAKE_C_COMPILER arm-none-eabi-gcc)
 set(CMAKE_SIZE arm-none-eabi-size)
+set(CMAKE_OBJCOPY arm-none-eabi-objcopy)
 
 # Include the module directories
 add_subdirectory(libs)
@@ -58,6 +59,7 @@ include_directories(${MODULES}/USBHost_t36)
 include_directories(${MODULES}/Wire)
 include_directories(${MODULES}/SD/src)
 include_directories(${MODULES}/SdFat/src)
+include_directories(${MODULES}/LittleFS/src)
 
 # include config.h and common headers
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/../..)
@@ -71,6 +73,10 @@ set(SOURCES
   src/module.cpp
   src/teensy.cpp
   src/ssd1306.cpp
+  src/i2c.cpp
+  src/serial.cpp
+  src/pinio.cpp
+  src/fs.cpp
 )
 
 # Add executable with the list of source files
diff --git a/src/platform/teensy/Makefile.am b/src/platform/teensy/Makefile.am
index 68b2c758..ed4091ad 100644
--- a/src/platform/teensy/Makefile.am
+++ b/src/platform/teensy/Makefile.am
@@ -25,6 +25,11 @@ build/smallbasic.elf : \
 	src/device.cpp \
 	src/teensy.cpp \
 	src/ssd1306.cpp \
+	src/fs.cpp \
+	src/i2c.cpp \
+	src/serial.cpp \
+	src/pinio.cpp \
+	src/module.cpp \
 	src/main_bas.h
 	@cd build && make -j 32
 
diff --git a/src/platform/teensy/README.md b/src/platform/teensy/README.md
index 317af58d..126acf4d 100644
--- a/src/platform/teensy/README.md
+++ b/src/platform/teensy/README.md
@@ -93,16 +93,16 @@ build/modules/teensy_loader_cli/teensy_loader_cli --mcu=TEENSY40 -w -v -s build/
 SMALLBASIC for Teensy offers three ways to upload and run a program.
 
 1. Format a SD card using FAT32. Rename your program to `MAIN.BAS` and copy it to the SD card.
-2. Include your program in the firmware. Replace `main.bas` in `src/platform/teensy` by your program and build
+2. Upload your program as `MAIN.BAS` to the flash memory file system (i.e. use `console.bas`)
+3. Include your program in the firmware. Replace `main.bas` in `src/platform/teensy` by your program and build
    the firmware.
-3. Send your program via USB-serial connection to the Teensy. In Linux use ` cat YourProgram.bas > /dev/ttyACM0`
+5. Send your program via USB-serial connection to the Teensy. In Linux use ` cat YourProgram.bas > /dev/ttyACM0`
    Change `/dev/ttyACM0` to the USB-serial port of your Teensy.
-4. Goto 3.
 
 When the Teensy starts up, it will check in the above indicated order for your program. If it finds
-a SD card and the SD card contains a file `MAIN.BAS`, it will execute it. Otherwise it will check, if a program
-was included in the firmware. If no program was included, the Teensy will switch to interactive mode and waits
-for a program upload via USB-serial.
+a SD card and the SD card contains a file `MAIN.BAS`, it will execute it. Otherwise it will check flash for
+the file `MAIN.bas` and executes it. Otherwise it will check, if a program was included in the firmware. If no
+program was included, the Teensy will switch to interactive mode and waits for a program upload via USB-serial.
 
 While your program is running, the Teensy will check continuously if data is available at the USB-serial port.
 If data is available for longer than one second your running program will be terminated and the queued data of the
@@ -114,7 +114,7 @@ If an error occurred, for example a syntax error, execution will stop and you ha
 the USB-serial port.
 
 If the execution of your program comes to an end, for example when reaching the end of the program or when `STOP` is
-called, the program is terminated and the next section in the above list is performed.
+called, the program is terminated and the teensy switches to interactive mode.
 
 # Read output from your running program
 
diff --git a/src/platform/teensy/libs/CMakeLists.txt b/src/platform/teensy/libs/CMakeLists.txt
index 05452b15..1439e8b1 100644
--- a/src/platform/teensy/libs/CMakeLists.txt
+++ b/src/platform/teensy/libs/CMakeLists.txt
@@ -16,6 +16,7 @@ set(USB_DIR ${MODULES_DIR}/USBHost_t36)
 set(WIRE_DIR ${MODULES_DIR}/Wire)
 set(SD_DIR ${MODULES_DIR}/SD/src)
 set(SDFAT_DIR ${MODULES_DIR}/SdFat/src)
+set(LITTLEFS_DIR ${MODULES_DIR}/LittleFS/src)
 
 set(SOURCES
   ${ADC_DIR}/ADC.cpp
@@ -162,6 +163,10 @@ set(SOURCES
   ${SDFAT_DIR}/common/FsUtf.cpp
   ${SDFAT_DIR}/common/PrintBasic.cpp
   ${SDFAT_DIR}/common/upcase.cpp
+  ${LITTLEFS_DIR}/LittleFS.cpp
+  ${LITTLEFS_DIR}/LittleFS_NAND.cpp
+  ${LITTLEFS_DIR}/littlefs/lfs.c
+  ${LITTLEFS_DIR}/littlefs/lfs_util.c
 )
 
 add_library(libs STATIC ${SOURCES})
@@ -176,4 +181,5 @@ target_include_directories(libs PRIVATE ${TEENSY_DIR})
 target_include_directories(libs PRIVATE ${WIRE_DIR})
 target_include_directories(libs PRIVATE ${SD_DIR})
 target_include_directories(libs PRIVATE ${SDFAT_DIR})
+target_include_directories(libs PRIVATE ${LITTLEFS_DIR})
 
diff --git a/src/platform/teensy/samples/SerialTerminal.bas b/src/platform/teensy/samples/SerialTerminal.bas
index 0eee365d..cfa54078 100644
--- a/src/platform/teensy/samples/SerialTerminal.bas
+++ b/src/platform/teensy/samples/SerialTerminal.bas
@@ -3,7 +3,7 @@ option base 1
 ReceiveBuffer = ""
 ComPort = "/dev/ttyACM0"
 ComSpeed = "115200"
-FileName = "serialUSB_receive_string.bas"
+FileName = "samples/console.bas"
 SendString = ""
 NumberLines = floor(YMAX / TextHeight("Qly")) - 1
 NumberRows  = floor(YMAX / TextWidth("W"))
@@ -33,93 +33,96 @@ const KeyF6 = ESC + Chr(0xF0 + 6)
 const KeyF9 = ESC + Chr(0xF0 + 9)
 const KeyF10 = ESC + Chr(0xF0 + 10)
 
+
+GetStartupParameter()
 Connect()
 PrintGUI()
 
 while(1)
-    'CheckIsConnected()
-    if(!isConnected) then Connect()
-    k = inkey
-    if(len(k))
-        select case k
-            case KeyReturn
-                Send(SendString)
-                SendHistory << SendString
-                SendHistoryIndex = ubound(SendHistory)
-                SendString = ""
-            case KeyEsc
-                SendString = ""
-            case KeyLeft
-            case KeyRight
-            case KeyDown
-                SendHistoryIndex = iff(SendHistoryIndex < ubound(SendHistory), SendHistoryIndex + 1, SendHistoryIndex)
-                SendString = SendHistory[SendHistoryIndex]
-            case KeyUp
-                SendHistoryIndex = iff(SendHistoryIndex > 0, SendHistoryIndex - 1, 0)
-                SendString = SendHistory[SendHistoryIndex]    
-            case KeyBackspace
-                SendString = chop(SendString)
-            case KeyF1
-                color 15,0
-                locate NumberLines - 1,0
-                print "\e[K";
-                Input "Enter COM port: ", ComPort
-                if(isConnected) then close #1
-                isConnected = 0
-            case KeyF2
-                color 15,0
-                locate NumberLines - 1,0
-                print "\e[K";
-                Input "Enter COM speed: ", ComSpeed
-                if(isConnected) then close #1
-                isConnected = 0
-            case KeyF3
-                'color 15,0
-                'locate NumberLines - 1,0
-                'print "\e[K";
-                'Input "Enter file name: ", FileName
-                showpage(1)
-                FileName = FileSelectDialog(0, 50, 50, XMAX - 100, YMAX - 100, 0)
-            case KeyF4
-                tsave "teensylog_" + ticks() + ".txt", ReceiveArray
-            case KeyF6
-                UploadFile()
-            case KeyF9
-                if(isConnected)
-                  close #1
-                  isConnected = 0
-                endif
-                ReceiveBuffer = ""
-                ReceiveArray = []
-            case KeyF10
-                if(isConnected) then close #1
-                stop
-           case else
-                SendString = SendString + k
-        end select
-        PrintGUI()
-    endif
-    
-    if(isConnected)
-      l = lof(1)
-      if(l)
-        ReceiveBuffer =  ReceiveBuffer + INPUT(l, 1)
-        split ReceiveBuffer, "\n", ReceiveArray
-        if(len(ReceiveArray) > NumberLines - 1)
-          n = len(ReceiveArray) - NumberLines + 1
-          delete ReceiveArray, 1, n
+  if(!isConnected) then Connect()
+  k = inkey
+  if(len(k))
+    select case k
+      case KeyReturn
+        Send(SendString)
+        SendHistory << SendString
+        SendHistoryIndex = ubound(SendHistory)
+        SendString = ""
+      case KeyEsc
+        SendString = ""
+      case KeyLeft
+      case KeyRight
+      case KeyDown
+        if(SendHistoryIndex > 0)
+          SendHistoryIndex = iff(SendHistoryIndex < ubound(SendHistory), SendHistoryIndex + 1, SendHistoryIndex)
+          SendString = SendHistory[SendHistoryIndex]
+        endif
+      case KeyUp
+        if(SendHistoryIndex > 0)
+          SendString = SendHistory[SendHistoryIndex]
+          SendHistoryIndex = iff(SendHistoryIndex > 1, SendHistoryIndex - 1, 1)
         endif
-        PrintGUI()
+      case KeyBackspace
+        SendString = chop(SendString)
+      case KeyF1
+        color 15,0
+        locate NumberLines - 1,0
+        print "\e[K";
+        Input "Enter COM port: ", ComPort
+        Input "Enter COM speed: ", ComSpeed
+        if(isConnected) then close #1
+        isConnected = 0
+      case KeyF3
+        if(instr(sbver(), "SDL"))
+          showpage(1)
+          FileName_temp = FileSelectDialog(0, 50, 50, XMAX - 100, YMAX - 100, 0)
+          if(FileName_temp != -1) then FileName = FileName_temp
+        else
+          color 15,0
+          repeat
+            locate NumberLines - 1,0
+            print "\e[K";
+            Input "Enter file name for upload: ", FileName
+          until(exist(FileName))
+        endif
+      case KeyF4
+        tsave "teensylog_" + ticks() + ".txt", ReceiveArray
+      case KeyF6
+        UploadFile()
+      case KeyF9
+        ReceiveBuffer = ""
+        ReceiveArray = []
+      case KeyF10
+        if(isConnected) then close #1
+        stop
+      case else
+        if(asc(k) > 31 AND asc(k) < 127)
+          SendString = SendString + k
+        endif
+    end select
+    PrintGUI()
+  endif
+
+  if(isConnected)
+    l = lof(1)
+    if(l)
+      ReceiveBuffer =  ReceiveBuffer + INPUT(l, 1)
+      split ReceiveBuffer, "\n", ReceiveArray
+      if(len(ReceiveArray) > NumberLines - 1)
+        n = len(ReceiveArray) - NumberLines + 1
+        delete ReceiveArray, 1, n
       endif
+      PrintGUI()
     endif
-    
-    delay(20)
-    showpage
+  endif
+  
+  delay(20)
+  showpage
 wend
 
 sub CheckIsConnected()
   local result
-  
+
   if(!isConnected) then return
 
   result = lof(1)
@@ -141,11 +144,12 @@ sub Connect()
     isConnected = 0
   end try
   PrintGUI()
+  print #1, "PRINT SBVER"
 end
 
 
 sub Send(s)
-  ReceiveBuffer = ReceiveBuffer + "\e[33m" + "> " + s + "\e[30m\n"
+  ' ReceiveBuffer = ReceiveBuffer + "\e[33m" + "> " + s + "\e[30m\n"
   print #1, s
 end
 
@@ -160,21 +164,17 @@ sub UploadFile()
 end
 
 sub PrintGUI()
-    color 7,1
+    color 15,0
     cls
-    
+
     for s in ReceiveArray
-      print "\e[0m";
-      color 14,1
-      print s
+      print s + "\e[0m"
     next
-    
-    print "\e[0m"
-    
+
     color 0, 7
     locate 0, 0
-    print "TEENSY Serial Terminal v1.0     |\e[35mF1\e[30m Port|\e[35mF2\e[30m Speed|\e[35mF3\e[30m File|\e[35mF4\e[30m Save|\e[35mF6\e[30m Upload|\e[35mF9\e[30m Reset|\e[35mF10\e[30m Quit\e[K"
-    
+    print "TEENSY Terminal v1.1 |\e[35mF1\e[30m Setup|\e[35mF3\e[30m File|\e[35mF4\e[30m Save|\e[35mF6\e[30m Upload|\e[35mF9\e[30m Clear|\e[35mF10\e[30m Quit\e[K"
+
     color 15, 0
     locate NumberLines - 1, 0
     print "Send: "; SendString; "\e[K";"\e[7m \e[27m"
@@ -189,6 +189,16 @@ sub PrintGUI()
     endif
 end
 
+sub GetStartupParameter()
+  local p
+  p = command()
+  split p, " ", parameters
+  
+  if(ubound(parameters) > 0)
+    FileName = parameters[1]
+  endif
+end
+
 
 func FileSelectDialog(Type, x, y, w, h, ButtonSize)
 ' Displays a file select dialog. If type is 0 (LOAD) then the function
@@ -220,29 +230,29 @@ func FileSelectDialog(Type, x, y, w, h, ButtonSize)
     color 15,0
     cls
     color TextColor, BGColor
-       
-    
+
+
     Directory = cwd()
-    
+
     if(ButtonSize == 0) then ButtonSize = 3 * Textwidth("W")    
-    
+
     func cmpfunc_strings(x, y)
-        x = lower(x)
-        y = lower(y)
-        
-        if x == y
-            return 0
-        elseif x > y
-            return 1
-        else
-            return -1
-        endif
+      x = lower(x)
+      y = lower(y)
+
+      if x == y
+        return 0
+      elseif x > y
+        return 1
+      else
+        return -1
+      endif
     end
-    
+
     func GetFileList()
         local FileList
         FileList = files("*")
-        
+
         for ii = 1 to ubound(FileList)
             if(isdir(FileList[ii])) then FileList[ii] = enclose(FileList[ii], "[]")                
         next
@@ -413,3 +423,5 @@ func FileSelectDialog(Type, x, y, w, h, ButtonSize)
 
 end
 
+
+
diff --git a/src/platform/teensy/samples/bt.bas b/src/platform/teensy/samples/bluetooth.bas
similarity index 100%
rename from src/platform/teensy/samples/bt.bas
rename to src/platform/teensy/samples/bluetooth.bas
diff --git a/src/platform/teensy/samples/hc-06.bas b/src/platform/teensy/samples/bluetooth_hc-06.bas
similarity index 100%
rename from src/platform/teensy/samples/hc-06.bas
rename to src/platform/teensy/samples/bluetooth_hc-06.bas
diff --git a/src/platform/teensy/samples/console.bas b/src/platform/teensy/samples/console.bas
new file mode 100644
index 00000000..fd986335
--- /dev/null
+++ b/src/platform/teensy/samples/console.bas
@@ -0,0 +1,493 @@
+' Console.bas provides a simple interface for
+' accessing flash (teensy 4.0 and 4.1), SD card
+' (teensy 4.1) and manipulating input and output
+' pins. After uploading this file to the teensy
+' type "help" for more information.
+
+import teensy
+
+const FS_READ = 0
+const FS_WRITE = 1
+
+const fs = teensy.fs
+const usbSerial = teensy.openSerial()
+
+teensy.SetInteractive(1)
+
+CurrentDirectory = ""
+
+print 
+print "\e[1mSmallBASIC console v1.0\e[0m"
+print "Type 'help' for a list of commands"
+
+while(1)
+  if(usbSerial.ready())
+    s = usbSerial.receive()
+    if(len(s) > 0)
+      s = trim(s)
+      SPLIT s, " ", v
+      cmd = lcase(v[0])
+
+      par_error = 1
+
+      select case cmd
+        case "ls"
+          if(ubound(v) > 0)
+            cmd_ls(v[1])
+          else
+            cmd_ls(-1)
+          endif
+          par_error = 0
+        case "cd"
+          if(ubound(v) > 0)
+            cmd_cd(v[1])
+            par_error = 0
+          endif
+        case "mv"
+          if(ubound(v) > 1) 
+            cmd_mv(v[1], v[2])
+            par_error = 0
+          endif
+        case "rm"
+          if(ubound(v) > 0)
+            cmd_rm(v[1])
+            par_error = 0
+          endif
+        case "cp"
+          if(ubound(v) > 1) 
+            cmd_cp(v[1], v[2])
+            par_error = 0
+          endif
+        case "mkdir"
+          if(ubound(v) > 0)
+            cmd_mkdir(v[1])
+            par_error = 0
+          endif
+        case "print"
+          if(ubound(v) > 0)
+            cmd_print(v[1])
+            par_error = 0
+          endif
+        case "exit"
+          print "See you soon."
+          exit
+        case "run"
+          if(ubound(v) > 0)
+            cmd_run(v[1])
+            par_error = 0
+          endif
+        case "getfile"
+          if(ubound(v) > 0)
+            cmd_getfile(v[1])
+            par_error = 0
+          endif
+        case "help"
+          cmd_help()
+        case "setpin"
+          if(ubound(v) > 1)
+            cmd_setpin(v[1], v[2])
+            par_error = 0
+          endif
+        case "getpin"
+          if(ubound(v) > 0)
+            cmd_getpin(v[1])
+            par_error = 0
+          endif
+        case "analogwrite"
+          if(ubound(v) > 1)
+            cmd_analogwrite(v[1], v[2])
+            par_error = 0
+          endif
+        case "analogread"
+          if(ubound(v) > 0)
+            cmd_analogread(v[1])
+            par_error = 0
+          endif
+        case "info"
+          cmd_info()
+        case "format"
+          cmd_format()
+      end select
+      if(par_error) then print_error("Parameter missing")
+    endif
+  else
+    delay(10)
+  endif
+wend
+
+func GetFullFile(f)
+  local Directory
+
+  if(f == -1) then return -1
+  if(f == "/") then return ""
+  if(right(f) == "/") then f = chop(f)
+
+  ' Absolute path starting with /
+  if(left(f, 4) == "/sd/") then return("sd:" + mid(f, 4))
+  if(f == "/sd") then return("sd:")
+  if(left(f, 7) == "/flash/") then return("flash:" + mid(f, 7))
+  if(f == "/flash") then return("flash:")
+  if(left(f) == "/") then return(-1)
+
+  ' path starts with one or more ../
+  Directory = CurrentDirectory
+  if(left(f, 3) == "../")
+    while(1)
+      if(left(f, 3) == "../")
+        Directory = leftoflast(Directory, "/")
+        f = mid(f, 4)
+      else
+        return GetFullFile(Directory + "/" + f)
+      endif
+    wend
+  endif
+
+  if(f == "..")
+    if(Directory == "/sd" or Directory == "/flash") then return ""
+    return GetFullFile(leftoflast(Directory, "/"))
+  endif
+
+  ' Relative path
+  if(CurrentDirectory == "/") then return(-1)
+  if(left(f, 2) == "./") then return(GetFullFile(CurrentDirectory + "/" + mid(f, 3)))
+  return(GetFullFile(CurrentDirectory + "/" + f))
+end
+
+sub cmd_ls(dir)
+  local file, path, file2, name
+
+  if(dir == -1 or dir == "/")
+    if(CurrentDirectory == "" or dir == "/")
+      print "\n\e[32m\e[1mList directory: /\e[0m"
+      print "\e[34m[flash]\n\e[34m[sd]\e[0m"
+      exit sub
+    endif
+    path = CurrentDirectory + "/"
+  else
+    path = dir
+  endif
+
+  path = GetFullFile(path) + "/"
+  if(path == -1)
+    print_error("Path not valid")
+    exit sub
+  endif
+
+  file = fs.open(path)
+  if(!file)
+    print_error("Path not found")
+    exit sub
+  endif  
+  if(!file.isDirectory())
+    file.close()
+    exit sub
+  endif
+
+  print "\n\e[32m\e[1mList directory "; path; "\e[0m"
+
+  while(1)
+    name = file.getNextFilename()
+    if(name == 0)
+      exit loop
+    endif
+
+    file2 = fs.open(path + name)
+    if(file2.isDirectory())
+      print "\e[34m[";name;"]\e[0m"
+    else
+      if(rightof(name,".") == "bas")
+        print "\e[35m\e[1m";name; "\t\t\e[0m "; file2.size(); " Bytes"
+      else
+        print name; "  "; "\t\t"; file2.size(); " Bytes"
+      endif
+    endif
+    file2.close()
+  wend
+  file.close()
+end
+
+sub cmd_cd(directory)
+  local file, path
+
+  path = GetFullFile(directory)
+  if(path == -1)
+    print_error("Path not valid")
+    exit sub
+  endif
+  if(path == "")
+    CurrentDirectory = ""
+    print "\nchange to directory /"
+    exit sub
+  endif
+
+  file = fs.open(path)
+  if(!file)
+    print_error("Not a directory")
+    exit sub
+  endif
+  
+  if(file.isDirectory())
+    if(left(path, 3) == "sd:")
+      CurrentDirectory = "/sd" + mid(path, 4)
+    else if(left(path, 6) == "flash:")
+      CurrentDirectory = "/flash" + mid(path, 7)
+    endif
+    if(right(CurrentDirectory) == "/") then CurrentDirectory = chop(CurrentDirectory)
+    print "\nchange to directory "; CurrentDirectory
+  else
+    print_error("Not a directory")
+  endif
+  file.close()
+end
+
+sub cmd_mv(a, b)
+  a = GetFullFile(a)
+  b = GetFullFile(b)
+
+  if(a == -1 or b == -1)
+    print_error("File not valid")
+    exit sub
+  endif
+
+  if(left(a) != left(b))
+    print_error("files can't be moved between different file systems")
+    exit sub
+  endif
+
+  print "\nmove "; a; " to "; b
+  if(!fs.rename(a,b)) then print_error("could not move file")
+end
+
+sub cmd_rm(f)
+  f = GetFullFile(f)
+  if(f == -1)
+    print_error("File not valid")
+    exit sub
+  endif
+
+  print "\nremove "; f
+  if(!fs.remove(f)) then print_error("could not remove file")
+end
+
+sub cmd_cp(f1, f2)
+  local file1, file2, s, path
+
+  f1 = GetFullFile(f1)
+  f2 = GetFullFile(f2)
+
+  if(a == -1 or b == -1)
+    print_error("File not valid")
+    exit sub
+  endif
+
+  print "\ncopy "; f1; " to "; f2
+  
+  file1 = OpenFile(f1)
+  if(!file1)
+    print_error("could not open source file")
+    exit sub
+  endif
+
+  file2 = fs.open(f2, FS_WRITE)
+  if(!file2)
+    file1.close()
+    print_error("could not open destination file")
+    exit sub
+  endif
+  file2.truncate()
+
+  while(file1.available())
+    s = file1.read(1)
+    file2.write(s)
+  wend
+
+  file1.close()
+  file2.close()
+end
+
+sub cmd_mkdir(dir)
+  dir = GetFullFile(dir)
+
+  if(dir == -1)
+    print_error("Directory not valid")
+    exit sub
+  endif
+
+  print "\ncreate directoy "; dir
+  if(!fs.mkdir(dir))
+    print_error("could not create directory")
+  endif
+end
+
+sub cmd_print(f)
+  local file, s
+
+  f = GetFullFile(f)
+  if(f == -1)
+    print_error("File not valid")
+    exit sub
+  endif
+
+  file = OpenFile(f)
+  if(!file)
+    exit sub
+  endif
+
+  while(file.available())
+    s = file.read(1)
+    print chr(s);
+  wend
+
+  file.close()
+end
+
+sub print_error(s)
+  print "\e[31mERROR: ";s;"\e[0m"
+end
+
+func OpenFile(name)
+  local file
+
+  file = fs.open(name, FS_READ)
+  if(!file)
+    print_error("not a file")
+    return 0
+  endif
+  if(file.isDirectory())
+    print_error("is directory")
+    file.close()
+    return 0
+  endif
+  return file
+end
+
+sub cmd_getfile(name)
+  local file, bytes, c
+  
+  name = GetFullFile(name)
+  if(name == -1)
+    print_error("File not valid")
+    exit sub
+  endif
+
+  file = fs.open(name, FS_WRITE)
+  if(!file)
+    print_error("could not write to file")
+    exit sub
+  endif
+  file.truncate()
+
+  print "\nWaiting for upload."
+  teensy.SetInteractive(0)
+
+  while(!usbSerial.ready())
+    delay(200)
+  wend
+
+  bytes = 0
+  while(usbSerial.ready())
+    c = usbSerial.receive(1)
+    file.write(c, 1)
+    bytes++
+  wend
+
+  file.close()
+  Print bytes; " Bytes received"
+  teensy.SetInteractive(1)
+end
+
+sub cmd_run(name)
+  local file, bytes, s
+
+  name = GetFullFile(name)
+  if(name == -1)
+    print_error("File not valid")
+    exit sub
+  endif
+
+  file = fs.open(name, FS_READ)
+  if(!file)
+    print_error("could not open file")
+    exit sub
+  endif
+
+  dim s
+  while(file.available())
+    s << file.read()
+  wend
+  chain s
+end
+
+sub cmd_format()
+  if(!fs.Quickformat()) then print_error("could not format flash")
+end
+
+sub cmd_help()
+  print
+  print "ls          | List files:  ls | ls /test | ls .."
+  print "cd          | Change directory: cd / | cd /dir1 | cd .."
+  print "cp          | Copy file: cp a.txt b.txt | cp a.txt /test/a.txt"
+  print "mv          | Move file: mv a.txt b.txt | mv a.txt /test/a.txt"
+  print "rm          | Delete file or direcrtory: rm a.txt | rm /test/a.txt"
+  print "mkdir       | Create directory: mkdir dir1 | mkdir dir1/dir2"
+  print "print       | Print file: print a.txt"
+  print "run         | Run file: run a.bas"
+  print "getfile     | Get file: getfile a.txt"
+  print "exit        | Exit console"
+  print "format      | Quickformat of flash file system"
+  print "info        | Print system information"
+  print "setpin      | Set pin to high or low: setpin 13 0 | setpin 13 1
+  print "getpin      | Get pin level. Returns high or low: getpin 10
+  print "analogwrite | Set pin to 0 to 255: analogwrite 13 128
+  print "analogread  | Get ADC value of pin: analogread 10
+  print
+  print "Absolute paths start with /"
+  print "Relative paths start without /"
+  print
+end
+
+sub cmd_setpin(PinNumber, level)
+  local Pin
+  PinNumber = val(PinNumber)
+  level = val(level)
+  Pin = teensy.openDigitalOutput(PinNumber)
+  Pin.write(level)
+end
+
+sub cmd_getpin(PinNumber)
+  local Pin
+  PinNumber = val(PinNumber)
+  Pin = teensy.openDigitalInput(PinNumber)
+  print Pin.read()
+end
+
+sub cmd_analogwrite(PinNumber, level)
+  local Pin
+  PinNumber = val(PinNumber)
+  level = val(level)
+  Pin = teensy.openAnalogOutput(PinNumber)
+  Pin.write(level)
+end
+
+sub cmd_analogread(PinNumber)
+  local Pin
+  PinNumber = val(PinNumber)
+  Pin = teensy.openAnalogInput(PinNumber)
+  print Pin.read()
+end
+
+sub cmd_info()
+  local RAM, FileSystem
+  RAM = teensy.free()
+  FileSystem = fs.free()
+  print "\n\e[1mMemory usage\e[0m"
+  print "STACK free : "; RAM[0]; " Bytes"
+  print "HEAP  free : "; RAM[1]; " Bytes"
+  print "FLASH used : "; FileSystem[0];  " Bytes"
+  print "FLASH total: "; FileSystem[1];  " Bytes"
+  print "SD    used : "; FileSystem[2];  " Bytes"
+  print "SD    total: "; FileSystem[3];  " Bytes"
+  print "\e[1mCPU\e[0m"
+  print "TEMP       : "; teensy.GetTemp(); " °C"
+  print "SPEED      : "; teensy.GetCPUSpeed(); " MHz"
+end
\ No newline at end of file
diff --git a/src/platform/teensy/samples/fs_copy_file.bas b/src/platform/teensy/samples/fs_copy_file.bas
new file mode 100644
index 00000000..a36be04e
--- /dev/null
+++ b/src/platform/teensy/samples/fs_copy_file.bas
@@ -0,0 +1,52 @@
+' Example for copying a file from flash to SD card
+
+import teensy
+
+const FS_READ = 0
+const FS_WRITE = 1
+
+fs = teensy.fs
+
+print "1. Create a test-file"
+print "   Open file for writing"
+file1 = fs.open("flash:/test.txt", FS_WRITE)
+print "   Remove file content (make file empty)"
+file1.truncate()
+print "   Write strings to file"
+file1.write("test1\n")
+print "      "; "test1"
+file1.write("test2\n")
+print "      "; "test2"
+file1.write("test3\n")
+print "      "; "test3"
+print "   Flush buffer (force writing)"
+file1.flush()
+print "   Close test file"
+file1.close()
+
+print "2. Copy test-file from flash to sd"
+print "   Open new file on sd"
+file_sd = fs.open("sd:/test.txt", FS_WRITE)
+print "      Remove file content (make file empty)"
+file_sd.truncate()
+print "   Open test-file on flash"
+file_flash = fs.open("flash:/test.txt", FS_READ)
+print "   Read data from flash and write to sd"
+while(file_flash.available())
+  s = file_flash.read(1)   ' read one byte
+  file_sd.write(s)
+wend
+print "   Close files"
+file_flash.close()
+file_sd.close()
+
+print "3. Print content of copied file"
+print "   Open file on sd"
+file_sd = fs.open("sd:/test.txt", FS_READ)
+print "   Read data:"
+while(file_sd.available())
+  s = file_sd.read()   ' read one line
+  print "      "; s
+wend
+print "   Close file"
+file_sd.close()
diff --git a/src/platform/teensy/samples/fs_flash_basic_io.bas b/src/platform/teensy/samples/fs_flash_basic_io.bas
new file mode 100644
index 00000000..541e8842
--- /dev/null
+++ b/src/platform/teensy/samples/fs_flash_basic_io.bas
@@ -0,0 +1,58 @@
+' Example for flash file access
+
+import teensy
+
+const FS_READ = 0
+const FS_WRITE = 1
+
+fs = teensy.fs
+
+'print "format flash"
+'fs.quickformat()
+
+print "1. Free space"
+r = fs.free()
+print "   Flash used size: ", r[0]
+print "   Flash total size: ", r[1]
+
+print "2. Create directory"
+fs.mkdir("flash:/TEST")
+print "   flash:/Test exists: "; fs.exists("flash:/TEST")
+
+print "3. Open file for writing"
+file1 = fs.open("flash:/test.txt", FS_WRITE)
+print "   Remove file content (make file empty)"
+file1.truncate()
+print "   Write string to file"
+file1.write("test1\n")
+file1.write("test2\n")
+file1.write("test3\n")
+print "   Flush buffer (force writing)"
+file1.flush()
+print "   Close file"
+file1.close()
+
+print "4. Read from file"
+file2 = fs.open("flash:/test.txt", FS_READ)
+size = file2.size()
+print "   Size of test.txt: "; size
+print "   Content of test.txt: "
+while(file2.available())
+  s = file2.read()
+  print "      "; s
+wend
+
+print "   Goto position 1 in file"
+file2.seek(1)
+print "   Get current position"
+print "      "; file2.position()
+print "   Read one line from current position"
+print "      "; file2.read()
+
+file2.close()
+
+print "5. Move file"
+fs.rename("flash:/test.txt", "flash:/test2.txt")
+
+print "6. Remove file"
+fs.remove("flash:/test2.txt")
diff --git a/src/platform/teensy/samples/fs_flash_list_files.bas b/src/platform/teensy/samples/fs_flash_list_files.bas
new file mode 100644
index 00000000..9cd8312a
--- /dev/null
+++ b/src/platform/teensy/samples/fs_flash_list_files.bas
@@ -0,0 +1,22 @@
+' Example for listing files in a directory of flash memory
+
+import teensy
+
+const FS_READ = 0
+const FS_WRITE = 1
+
+fs = teensy.fs
+
+file = fs.open("flash:/")
+
+while(1)
+  s = ""
+  name = file.getNextFilename()
+  if(name == 0) then exit
+  
+  file2 = fs.open(name)
+  if(file2.isDirectory()) then s = "/"
+  file2.close()
+  print name; s
+wend
+
diff --git a/src/platform/teensy/samples/fs_sd_basic_io.bas b/src/platform/teensy/samples/fs_sd_basic_io.bas
new file mode 100644
index 00000000..fa3d7ddd
--- /dev/null
+++ b/src/platform/teensy/samples/fs_sd_basic_io.bas
@@ -0,0 +1,55 @@
+' Example for SD card file access
+
+import teensy
+
+const FS_READ = 0
+const FS_WRITE = 1
+
+fs = teensy.fs
+
+print "1. Free space"
+r = fs.free()
+print "   SD used size: ", r[2]
+print "   SD total size: ", r[3]
+
+print "2. Create directory"
+fs.mkdir("sd:/TEST")
+print "   sd:/Test exists: "; fs.exists("sd:/TEST")
+
+print "3. Open file for writing"
+file1 = fs.open("sd:/test.txt", FS_WRITE)
+print "   Remove file content (make file empty)"
+file1.truncate()
+print "   Write string to file"
+file1.write("sdtest1\n")
+file1.write("sdtest2\n")
+file1.write("sdtest3\n")
+print "   Flush buffer (force writing)"
+file1.flush()
+print "   Close file"
+file1.close()
+
+print "4. Read from file"
+file2 = fs.open("sd:/test.txt", FS_READ)
+size = file2.size()
+print "   Size of test.txt: "; size
+print "   Content of test.txt: "
+while(file2.available())
+  s = file2.read()
+  print "      "; s
+wend
+
+print "   Goto position 1 in file"
+file2.seek(1)
+print "   Get current position"
+print "      "; file2.position()
+print "   Read one line from current position"
+print "      "; file2.read()
+
+file2.close()
+
+print "5. Move file"
+fs.rename("sd:/test.txt", "sd:/test2.txt")
+
+print "6. Remove file"
+fs.remove("sd:/test2.txt")
diff --git a/src/platform/teensy/samples/hd44780.bas b/src/platform/teensy/samples/hd44780.bas
new file mode 100644
index 00000000..e4bb8965
--- /dev/null
+++ b/src/platform/teensy/samples/hd44780.bas
@@ -0,0 +1,218 @@
+' HD44780 - Text LCD
+' ==================
+'
+' This example demonstrates how to use the alphanumeric
+' dot matrix liquid crystal display HD44780.
+' 
+' Connect the LCD to the Teensy board:
+'
+' --------         --------                 1 (GND)
+'  TEENSY |       |HD44780                  |
+'  5      |-------|11 (DB4)                ---
+'  4      |-------|12 (DB5)               |   |
+'  3      |-------|13 (DB6)               |10K|<---3 (VEE)
+'  2      |-------|14 (DB7)               |   |
+'  GND    |-------| 5 (RW)                 --- 
+'  1      |-------| 6 (E)                   |
+'  0      |-------| 4 (RS)                  2 (VIN)
+'  Vin    |-------| 2 (VIN)
+'  GND    |-------| 1 (GND)
+' --------         --------
+'
+' A potentiometer needs to be connected to the display
+' to control the contrast of the display. If the display
+' has a background light, connect power according to the
+' data sheet to the pins 15 and 16.
+'
+' Edit Init() according to your display. Initial setting are:
+'  - Display with 2 lines
+'  - Cursor off
+'  - Blinking off
+'  - 5x7 font
+'
+' Code based on https://www.mikrocontroller.net/articles/AVR-GCC-Tutorial/LCD-Ansteuerung
+
+'#########################################################
+'# Constant definition                                   #
+'#########################################################
+
+const LCD_CLEAR_DISPLAY  = 0x01
+const LCD_CURSOR_HOME    = 0x02
+
+const LCD_SET_ENTRY      = 0x04
+const LCD_ENTRY_DECREASE = 0x00
+const LCD_ENTRY_INCREASE = 0x02
+const LCD_ENTRY_NOSHIFT  = 0x00
+const LCD_ENTRY_SHIFT    = 0x01
+
+const LCD_SET_DISPLAY    = 0x08
+const LCD_DISPLAY_OFF    = 0x00
+const LCD_DISPLAY_ON     = 0x04
+const LCD_CURSOR_OFF     = 0x00
+const LCD_CURSOR_ON      = 0x02
+const LCD_BLINKING_OFF   = 0x00
+const LCD_BLINKING_ON    = 0x01
+
+const LCD_SET_SHIFT      = 0x10
+const LCD_CURSOR_MOVE    = 0x00
+const LCD_DISPLAY_SHIFT  = 0x08
+const LCD_SHIFT_LEFT     = 0x00
+const LCD_SHIFT_RIGHT    = 0x04
+
+const LCD_SET_FUNCTION   = 0x20
+const LCD_FUNCTION_4BIT  = 0x00
+const LCD_FUNCTION_8BIT  = 0x10
+const LCD_FUNCTION_1LINE = 0x00
+const LCD_FUNCTION_2LINE = 0x08
+const LCD_FUNCTION_5X7   = 0x00
+const LCD_FUNCTION_5X10  = 0x04
+
+const LCD_SOFT_RESET     = 0x30
+
+const LCD_SET_CGADR      = 0x40
+const LCD_SET_DDADR      = 0x80 
+const LCD_DDADR_LINE1    = 0x00
+const LCD_DDADR_LINE2    = 0x40
+const LCD_DDADR_LINE3    = 0x10
+const LCD_DDADR_LINE4    = 0x50
+
+'#########################################################
+'# Main program                                          #
+'#########################################################
+
+import teensy
+
+LCD_Init(0,1,2,3,4,5)
+
+LCD_Write("  Hello  World")
+LCD_Locate(1,2)
+LCD_Write("-= SmallBASIC =-")
+print "Done"
+
+end
+
+ 
+'#########################################################
+'# Functions and subs                                    #
+'#########################################################
+
+sub LCD_Init(PinRS, PinE, PinDB4, PinDB5, PinDB6, PinDB7)
+  Print "Connect to HD44780"
+  RS  = teensy.openDigitalOutput(PinRS)
+  E   = teensy.openDigitalOutput(PinE)
+  DB4 = teensy.openDigitalOutput(PinDB4)
+  DB5 = teensy.openDigitalOutput(PinDB5)
+  DB6 = teensy.openDigitalOutput(PinDB6)
+  DB7 = teensy.openDigitalOutput(PinDB7)
+  Print "Connection established"
+
+  RS.write(0)
+  E.write(0)
+  DB4.write(0)
+  DB5.write(0)
+  DB6.write(0)
+  DB7.write(0)
+
+  delay(50)
+
+  ' Send soft-reset 3 time to initialize LCD
+  Send4Bit(LCD_SOFT_RESET)
+  delay(5) 
+  SendEnable()
+  delay(1)
+  SendEnable()
+  delay(1)
+
+  ' Set 4-bit mode
+  Send4Bit(LCD_SET_FUNCTION BOR LCD_FUNCTION_4BIT)
+  delay(5)
+
+  ' 2 lines and 5x7 pixel in 4 bit mode
+  SendCommand(LCD_SET_FUNCTION BOR LCD_FUNCTION_4BIT BOR LCD_FUNCTION_2LINE BOR LCD_FUNCTION_5X7)
+  ' Display on, cursor off and blinking off
+  SendCommand(LCD_SET_DISPLAY BOR LCD_DISPLAY_ON BOR LCD_CURSOR_OFF BOR LCD_BLINKING_OFF)
+  ' Cursor increment no scrolling
+  SendCommand(LCD_SET_ENTRY BOR LCD_ENTRY_INCREASE BOR LCD_ENTRY_NOSHIFT)
+
+  LCD_Cls()
+end
+
+sub LCD_Write(Text)
+  ' Write characters to lcd
+  local length, t
+  length = len(Text)
+  
+  for i = 1 to length
+    t = asc(mid(text, i, 1))
+    SendData(t)
+  next
+end
+
+sub LCD_Cls()
+  SendCommand(LCD_CLEAR_DISPLAY)
+  SendCommand(LCD_CURSOR_HOME)
+end
+
+sub LCD_Off()
+  SendCommand(LCD_SET_DISPLAY BOR LCD_DISPLAY_OFF)
+end
+
+sub LCD_On()
+  ' Display on, cursor off and blinking off
+  SendCommand(LCD_SET_DISPLAY BOR LCD_DISPLAY_ON BOR LCD_CURSOR_OFF BOR LCD_BLINKING_OFF)
+end
+
+sub LCD_Locate(x, y)
+  local dat
+
+  if(x < 1) then x == 1
+  
+  select case y
+    case 1     ' 1. line
+      dat = LCD_SET_DDADR + LCD_DDADR_LINE1 + x - 1
+    case 2     ' 2. line
+      dat = LCD_SET_DDADR + LCD_DDADR_LINE2 + x - 1
+    case 3     ' 3. line
+      dat = LCD_SET_DDADR + LCD_DDADR_LINE3 + x - 1
+    case 4     ' 4. line
+      dat = LCD_SET_DDADR + LCD_DDADR_LINE4 + x - 1
+    case else
+      return
+  end select
+
+  SendCommand(dat)
+end
+
+sub SendCommand(cmd)
+  RS.write(0)
+  SendByte(cmd)
+end
+
+sub SendData(dat)
+  RS.write(1)
+  SendByte(dat)
+end
+
+sub SendEnable()
+  E.write(1)
+  delay(1)
+  E.write(0)
+  delay(1)
+end
+
+sub SendByte(byte)
+  Send4Bit(byte)          ' Send high bits first
+  Send4Bit(byte lshift 4) ' Send low bits
+end
+
+sub Send4Bit(byte)
+  DB7.write(GetBit(byte, 7))
+  DB6.write(GetBit(byte, 6))
+  DB5.write(GetBit(byte, 5))
+  DB4.write(GetBit(byte, 4))
+  SendEnable()  
+end
+
+func GetBit(value, bit)
+  return (value rshift bit) BAND 1
+end
\ No newline at end of file
diff --git a/src/platform/teensy/samples/i2c_bh1750.bas b/src/platform/teensy/samples/i2c_bh1750.bas
index 5dd2d24d..ffa23590 100644
--- a/src/platform/teensy/samples/i2c_bh1750.bas
+++ b/src/platform/teensy/samples/i2c_bh1750.bas
@@ -1,3 +1,17 @@
+' I2C: BH1750 - Ambient Light Sensor
+' =====================================================
+'
+' This example demonstrates how to use a BH1750 ambient
+' light sensor with the I2C interface.
+'
+' ---------------         ----------
+'  Teensy        |       | BH1750
+'  3.3V          |-------| VCC
+'  PIN 17 (SDA1) |-------| SDA 
+'  PIN 16 (SCL1) |-------| SCL
+'  GND           |-------| GND
+'----------------         ---------
+
 import teensy
 
 const ADDRESS = 0x23
diff --git a/src/platform/teensy/samples/i2c_bmp180.bas b/src/platform/teensy/samples/i2c_bmp180.bas
index 095a5c93..67ffc80d 100644
--- a/src/platform/teensy/samples/i2c_bmp180.bas
+++ b/src/platform/teensy/samples/i2c_bmp180.bas
@@ -1,3 +1,17 @@
+' I2C: BMP180 - Pressure and temperature sensor
+' =====================================================
+'
+' This example demonstrates how to use a BMP180
+' pressure and temperature sensor with the I2C interface.
+'
+' ---------------         ----------
+'  Teensy        |       | BMP180
+'  3.3V          |-------| VIN
+'  PIN 17 (SDA1) |-------| SDA 
+'  PIN 16 (SCL1) |-------| SCL
+'  GND           |-------| GND
+'----------------         ---------
+
 import teensy
 
 const ADDRESS = 0x77
diff --git a/src/platform/teensy/samples/i2c_mpu6050.bas b/src/platform/teensy/samples/i2c_mpu6050.bas
new file mode 100644
index 00000000..aaaa79ca
--- /dev/null
+++ b/src/platform/teensy/samples/i2c_mpu6050.bas
@@ -0,0 +1,201 @@
+' MPU6050 - I2C accelerometer and gyroscope
+'
+' Pins:
+'   TEENSY      MPU6050
+'   16 SCL1 --> SCL
+'   17 SDA1 --> SDA
+'      3.3V --> VCC
+'      GND  --> GND
+
+import teensy
+
+const ADDRESS = 0x68
+
+Init()
+
+currentTime = ticks()
+lastUpdate = ticks()
+
+while(1)
+  ' Read accelerometer data
+  Accel = GetAcceleration()
+  AccX = Accel[0]
+  AccY = Accel[1]
+  AccZ = Accel[2]
+
+  ' Get delta time
+  previousTime = currentTime
+  currentTime = ticks()
+  dt = (currentTime - previousTime) / 1000
+
+  ' Read gyroscope data
+  Gyro = GetGyroscope()
+  GyroX = Gyro[0]
+  GyroY = Gyro[1]
+  GyroZ = Gyro[2]
+
+  ' Calc roll and pitch using acceleration sensor
+  AccRoll = atan2(AccY, AccZ) * 180 / PI
+  AccPitch = atan2(-AccX, sqr(AccY^2 + AccZ^2)) * 180/PI
+
+  ' Calc roll and pitch unsing gyroscope and accelerometer to reduce noise and cancel drift
+  roll = 0.98 * (roll + GyroX * dt) + 0.02 * AccRoll
+  pitch = 0.98 * (pitch + GyroY * dt) + 0.02 * AccPitch
+
+  ' Display every 500ms
+  if(ticks() - lastUpdate > 500)
+    print "Roll : "; round(roll, 2), " Pitch : "; round(pitch, 2), " Temperature: "; round(GetTemperature(),1); "°C"
+    ' uncomment to see roll and pitch measured with accelerometer only
+    ' print "AccRoll : "; round(AccRoll, 2), " AccPitch: "; round(AccPitch, 2)
+    lastUpdate = ticks()
+  endif
+wend
+
+' #### Functions #############################################
+
+sub Init()
+  local buffer, Who_am_I
+
+  Print "Open I2C...";
+  const I2C = teensy.OpenI2C(1)   ' use I2C pins 16 and 17
+  Print "Opened"
+
+  ' Test if sensor is present
+  I2C.write(ADDRESS, 0x75)
+  Who_am_I = I2C.read(ADDRESS, 1)
+  if(Who_am_I != 0x68 AND Who_am_I != 0x69)
+    print "Error: MPU6050 WHO_AM_I value wrong"
+    stop
+  endif
+
+  ' Set SMPLRT_DIV to 0
+  ' Sample Rate = Gyroscope Output Rate / (1 + SMPLRT_DIV)
+  buffer = [0x19, 0]
+  I2C.write(ADDRESS, buffer)
+
+  ' MPU config
+  ' external Frame Synchronization disabled
+  buffer = [0x1A, 0]
+  I2C.write(ADDRESS, buffer)
+
+  GyroscopeConfig(250)
+  AccelerationConfig(2)
+
+  ' Turn on
+  buffer = [0x6B, 0x01]
+  I2C.write(ADDRESS, buffer)
+end
+
+func short(dat)
+    if dat > 32767 then
+        return dat - 65536
+    else
+        return dat
+    endif
+end
+
+func GetAcceleration()
+  local buffer, AccX, AccY, AccZ
+  dim buffer[5]
+
+  I2C.write(ADDRESS, 0x3B)
+  buffer = I2C.read(ADDRESS, 6)
+
+  AccX = short((buffer[0] lshift 8) BOR buffer[1]) / AccelerationLSBSensitivity
+  AccY = short((buffer[2] lshift 8) BOR buffer[3]) / AccelerationLSBSensitivity
+  AccZ = short((buffer[4] lshift 8) BOR buffer[5]) / AccelerationLSBSensitivity
+
+  return [AccX, AccY, AccZ]
+end
+
+func GetGyroscope()
+  local buffer, GyroX, GyroY, GyroZ
+  dim buffer[5]
+
+  I2C.write(ADDRESS, 0x43)
+  buffer = I2C.read(ADDRESS, 6)
+
+  ' Correct the outputs with the error values
+  GyroX = short((buffer[0] lshift 8) BOR buffer[1]) / GyroscopeLSBSensitivity
+  GyroY = short((buffer[2] lshift 8) BOR buffer[3]) / GyroscopeLSBSensitivity
+  GyroZ = short((buffer[4] lshift 8) BOR buffer[5]) / GyroscopeLSBSensitivity
+
+  return [GyroX, GyroY, GyroZ]
+end
+
+func GetTemperature()
+  local buffer, Temp
+  dim buffer[1]
+
+  I2C.write(ADDRESS, 0x41)
+  buffer = I2C.read(ADDRESS, 2)
+
+  Temp = short((buffer[0] lshift 8) BOR buffer[1]) / 340.0 + 36.53
+
+  return Temp
+end
+
+' GyroscopeConfig(range)
+' Sets the full scale range of the Gyroscope. Range can have the
+' values 250, 500, 1000, or 2000 in °/s.
+sub GyroscopeConfig(range)
+  local Setting, buffer
+  dim buffer[1]
+
+  select case range
+    case 250
+      Setting = 0x00
+      GyroscopeLSBSensitivity = 131.0
+    case 500
+      Setting = 0x08
+      GyroscopeLSBSensitivity = 65.5
+    case 1000
+      Setting = 0x10
+      GyroscopeLSBSensitivity = 32.8
+    case 2000
+      Setting = 0x18
+      GyroscopeLSBSensitivity = 16.4
+    case else
+      Setting = 0x00
+      GyroscopeLSBSensitivity = 131.0
+  end select
+
+  buffer[0] = 0x1B
+  buffer[1] = Setting
+  I2C.write(ADDRESS, buffer)
+end
+
+' Accelerometer Configuration
+'  AccelerationConfig(range)
+'  Sets the full scale range of the Accelerometer. Range can have the
+'  values 2, 4, 8, or 16, which corresponds to the following g-force
+'  2 ->  2g
+'  4 ->  4g
+'  8 ->  8g
+'  16 -> 16g
+sub AccelerationConfig(range)
+  local setting, buffer
+  dim buffer[1]
+
+  select case range
+    case 2
+      Setting = 0x00
+      AccelerationLSBSensitivity = 16384
+    case 4
+      Setting = 0x08
+      AccelerationLSBSensitivity = 8192
+    case 8
+      Setting = 0x10
+      AccelerationLSBSensitivity = 4096
+    case 16
+      Setting = 0x18
+      AccelerationLSBSensitivity = 2048
+    case else
+      Setting = 0x00
+      AccelerationLSBSensitivity = 16384
+  end select
+
+  buffer[0] = 0x1C
+  buffer[1] = Setting
+  I2C.write(ADDRESS, buffer)
+end
\ No newline at end of file
diff --git a/src/platform/teensy/samples/pwm_led.bas b/src/platform/teensy/samples/io_analog_pwm_led.bas
similarity index 100%
rename from src/platform/teensy/samples/pwm_led.bas
rename to src/platform/teensy/samples/io_analog_pwm_led.bas
diff --git a/src/platform/teensy/samples/pwm_led_2.bas b/src/platform/teensy/samples/io_analog_pwm_led_2.bas
similarity index 100%
rename from src/platform/teensy/samples/pwm_led_2.bas
rename to src/platform/teensy/samples/io_analog_pwm_led_2.bas
diff --git a/src/platform/teensy/samples/io_analog_read.bas b/src/platform/teensy/samples/io_analog_read.bas
new file mode 100644
index 00000000..616bcbd6
--- /dev/null
+++ b/src/platform/teensy/samples/io_analog_read.bas
@@ -0,0 +1,23 @@
+' Analog IO - Potentiometer
+' =====================================================
+'
+' This example demonstrates how to read an analog
+' voltage using a potentiometer.
+'
+' ----------
+'  TEENSY   |
+'  3.3V     |-------- 1 ---/\/\/\--- 3 --
+'           |                 |          |
+'  PIN 23   |---------------- 2          |
+'           |                            |
+'  GND      |----------------------------
+' ----------
+
+import teensy
+
+const Potentiometer = teensy.openAnalogInput(23)
+
+for ii = 1 to 50
+  print ii, Potentiometer.read()
+  delay(500)
+next
\ No newline at end of file
diff --git a/src/platform/teensy/samples/led.bas b/src/platform/teensy/samples/io_digital_led.bas
similarity index 100%
rename from src/platform/teensy/samples/led.bas
rename to src/platform/teensy/samples/io_digital_led.bas
diff --git a/src/platform/teensy/samples/io_digital_read.bas b/src/platform/teensy/samples/io_digital_read.bas
new file mode 100644
index 00000000..a4efe246
--- /dev/null
+++ b/src/platform/teensy/samples/io_digital_read.bas
@@ -0,0 +1,19 @@
+' Digital IO - Push Button
+' =====================================================
+'
+' This example demonstrates how to use a push button.
+'
+' ----------         ----------
+'  TEENSY   |       | Button
+'  PIN 0    |-------| Pin 1 
+'  GND      |-------| Pin 2
+' ----------         ---------
+
+import teensy
+
+const Pushbutton = teensy.openDigitalInput(0)
+
+for ii = 1 to 20
+  print ii, Pushbutton.read()
+  delay(500)
+next
diff --git a/src/platform/teensy/samples/serialprint.bas b/src/platform/teensy/samples/serial_print.bas
similarity index 100%
rename from src/platform/teensy/samples/serialprint.bas
rename to src/platform/teensy/samples/serial_print.bas
diff --git a/src/platform/teensy/samples/serialUSB_receive_bytes.bas b/src/platform/teensy/samples/serial_receive_bytes.bas
similarity index 69%
rename from src/platform/teensy/samples/serialUSB_receive_bytes.bas
rename to src/platform/teensy/samples/serial_receive_bytes.bas
index 783dd860..9851daf0 100644
--- a/src/platform/teensy/samples/serialUSB_receive_bytes.bas
+++ b/src/platform/teensy/samples/serial_receive_bytes.bas
@@ -2,18 +2,22 @@ import teensy
 
 const usbSerial = teensy.openSerial()
 const BuiltInLED = teensy.openDigitalOutput(13)
-value = 0
 
 teensy.SetInteractive(1)
 
+print
+print "Receive two bytes over serial connection"
+print "Send Q1 to exit program"
+print
+
 while(1)
   if(usbSerial.ready()) then
-    s = usbSerial.read(2)
+    s = usbSerial.receive(2)
     print s
     if(len(s) == 2) then
       if(s[0] == 81) then     ' if first Byte is a Q
-          print "Quit program."
-          stop
+        print "Quit program."
+        stop
       endif
     endif
   else
@@ -25,5 +29,3 @@ while(1)
   BuiltInLED.write(0)
   delay(25)
 wend
-
-
diff --git a/src/platform/teensy/samples/serialUSB_receive_string.bas b/src/platform/teensy/samples/serial_receive_string.bas
similarity index 75%
rename from src/platform/teensy/samples/serialUSB_receive_string.bas
rename to src/platform/teensy/samples/serial_receive_string.bas
index 11e9e906..5e76f772 100644
--- a/src/platform/teensy/samples/serialUSB_receive_string.bas
+++ b/src/platform/teensy/samples/serial_receive_string.bas
@@ -6,6 +6,13 @@ value = 0
 
 teensy.SetInteractive(1)
 
+print
+print "Receive a string over serial connection"
+print "Send following strings: "
+print "led   -> turn onboard LED on or off"
+print "quit  -> exit program"
+print
+
 while(1)
   if(usbSerial.ready()) then
     s = usbSerial.receive()
diff --git a/src/platform/teensy/setup.sh b/src/platform/teensy/setup.sh
index 294867ff..87f772d8 100755
--- a/src/platform/teensy/setup.sh
+++ b/src/platform/teensy/setup.sh
@@ -3,25 +3,26 @@
 DIR=`pwd`
 
 (mkdir -p build/modules && cd build/modules && \
-	git clone https://github.com/PaulStoffregen/cores.git && \
-	git clone https://github.com/PaulStoffregen/SPI.git && \
-	git clone https://github.com/PaulStoffregen/Wire.git && \
-	git clone https://github.com/PaulStoffregen/USBHost_t36.git && \
+  git clone https://github.com/PaulStoffregen/cores.git && \
+  git clone https://github.com/PaulStoffregen/SPI.git && \
+  git clone https://github.com/PaulStoffregen/Wire.git && \
+  git clone https://github.com/PaulStoffregen/USBHost_t36.git && \
   git clone https://github.com/PaulStoffregen/SD.git && \
-	git clone https://github.com/PaulStoffregen/SdFat.git && \
-	git clone https://github.com/PaulStoffregen/teensy_loader_cli.git && \
-	git clone https://github.com/pedvide/ADC && \
-	git clone https://github.com/ARM-software/CMSIS_5.git && \
-	git clone https://github.com/ARM-software/CMSIS-DSP.git && \
-	git clone https://github.com/adafruit/Adafruit_SSD1306.git && \
-	git clone https://github.com/adafruit/Adafruit-GFX-Library && \
-	git clone https://github.com/adafruit/Adafruit_BusIO)
+  git clone https://github.com/PaulStoffregen/SdFat.git && \
+  git clone https://github.com/PaulStoffregen/teensy_loader_cli.git && \
+  git clone https://github.com/pedvide/ADC && \
+  git clone https://github.com/ARM-software/CMSIS_5.git && \
+  git clone https://github.com/ARM-software/CMSIS-DSP.git && \
+  git clone https://github.com/adafruit/Adafruit_SSD1306.git && \
+  git clone https://github.com/adafruit/Adafruit-GFX-Library && \
+  git clone https://github.com/adafruit/Adafruit_BusIO && \
+  git clone https://github.com/PaulStoffregen/LittleFS)
 
 (cd build/modules/CMSIS-DSP && \
-    mkdir -p build && \
-    cd build && \
-    cmake .. -Wno-dev -DARM_CPU=cortex-m7 -DUSE_FPU=ON -DFLOAT_ABI=hard -DCMAKE_C_FLAGS="-I${DIR}/build/modules/CMSIS_5/CMSIS/Core/Include" && \
-    cmake --build .)
+  mkdir -p build && \
+  cd build && \
+  cmake .. -Wno-dev -DARM_CPU=cortex-m7 -DUSE_FPU=ON -DFLOAT_ABI=hard -DCMAKE_C_FLAGS="-I${DIR}/build/modules/CMSIS_5/CMSIS/Core/Include" && \
+  cmake --build .)
 
 (cd build/modules/teensy_loader_cli && make)
 
diff --git a/src/platform/teensy/src/fs.cpp b/src/platform/teensy/src/fs.cpp
new file mode 100644
index 00000000..99f59523
--- /dev/null
+++ b/src/platform/teensy/src/fs.cpp
@@ -0,0 +1,370 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2026 Joerg Siebenmorgen
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#include <Arduino.h>
+#include "common/device.h"
+#include "common/pproc.h"
+#include "config.h"
+#include "languages/messages.en.h"
+#include "include/var_map.h"
+#include "module.h"
+#include <SD.h>
+#include <LittleFS.h>
+#include <vector>
+
+extern LittleFS_Program flashfs;
+
+std::vector<File> fileStack;
+
+/*
+ * close file
+ */
+static int cmd_close(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  fileStack[self->v.m.id].flush();
+  fileStack[self->v.m.id].close();
+  return 1;
+}
+
+/*
+ * if current file is a directory, getNextFilename() returns
+ * the next filename in the directory
+ */
+static int cmd_getNextFilename(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  File file = fileStack[self->v.m.id].openNextFile();
+  if (!file) {
+    v_setint(retval, 0);
+    return 1;
+  }
+
+  v_setstr(retval, file.name());
+
+  file.close();
+  return 1;
+}
+
+/*
+ * check if file is a directory
+ * isDirectory() returns true or false
+ */
+static int cmd_isDirectory(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  v_setint(retval, fileStack[self->v.m.id].isDirectory());
+  return 1;
+}
+
+/*
+ * return file size
+ */
+static int cmd_size(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  v_setint(retval, fileStack[self->v.m.id].size());
+  return 1;
+}
+
+/*
+ * return current read/write position
+ */
+static int cmd_position(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  v_setint(retval, fileStack[self->v.m.id].position());
+  return 1;
+}
+
+/*
+ * set read/write position
+ * seek(pos)  -> 'pos' psition in file
+ */
+static int cmd_seek(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  uint64_t pos = get_param_int(argc, args, 0, 0);
+  fileStack[self->v.m.id].seek(pos);
+  return 1;
+}
+
+/*
+ * read from file
+ * 1. read() or read(0) -> read until '\n' and return as string
+ * 2. read(1)           -> read one byte and return as integer
+ * 2. read(n)           -> read n bytes and return as integer array
+ */
+static int cmd_read(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  uint32_t bytes = get_param_int(argc, args, 0, 0);
+  int size;
+
+  if (bytes == 0) {
+    // Read until '\n' and return as string
+    bytes = CDC_RX_SIZE_480;
+    char buffer[bytes];
+    size = fileStack[self->v.m.id].readBytesUntil('\n', buffer, bytes - 1);
+    buffer[size] = '\0';
+    v_setstr(retval, buffer);
+  } else if (bytes > 1) {
+    // Read number of bytes and return as array
+    v_toarray1(retval, bytes);
+    for (uint32_t ii = 0; ii < bytes; ii++) {
+      v_setint(v_elem(retval, ii), fileStack[self->v.m.id].read());
+    }
+  } else {
+    v_setint(retval, fileStack[self->v.m.id].read());
+  }
+  return 1;
+}
+
+/*
+ * write to file
+ * wrtie(buffer) -> 'buffer' can be integer, string or array
+ */
+static int cmd_write(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  switch (args[0].var_p->type) {
+  case V_INT:{
+      uint8_t value = get_param_int(argc, args, 0, 0);
+      fileStack[self->v.m.id].write(value);
+    }
+    break;
+  case V_STR:{
+      const char *buffer = get_param_str(argc, args, 0, "");
+      fileStack[self->v.m.id].print(buffer);
+    }
+    break;
+  case V_ARRAY:{
+      var_p_t array = args[1].var_p;    // Get array
+      if (array->maxdim > 1) {
+        v_setstr(retval, "ERROR: FS: Write requires 1D-array");
+        return 0;
+      }
+      uint32_t bytes = v_ubound(array, 0) - v_lbound(array, 0) + 1;
+      uint8_t *buffer = new uint8_t[bytes];
+      for (uint32_t ii = 0; ii < bytes; ii++) {
+        buffer[ii] = get_array_elem_int(array, ii);
+      }
+      fileStack[self->v.m.id].write(buffer, bytes);
+      delete[]buffer;
+    }
+    break;
+  }
+
+  return 1;
+}
+
+/*
+ * flush buffer and sync file
+ */
+static int cmd_flush(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  fileStack[self->v.m.id].flush();
+  return 1;
+}
+
+/*
+ * convert current file, which might contain data, to an empty file
+ */
+static int cmd_truncate(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  fileStack[self->v.m.id].truncate();
+  fileStack[self->v.m.id].seek(0);
+  return 1;
+}
+
+/*
+ * returns bytes available for reading
+ */
+static int cmd_available(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  v_setint(retval, fileStack[self->v.m.id].available());
+  return 1;
+}
+
+/*
+ * open a file or directory
+ * open(name, mode) -> open file 'name' with rwmode 'mode'; mode = 0 -> read; mode = 1 -> write
+ * open() returns a map
+ */
+static int cmd_open(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  const char *name = get_param_str(argc, args, 0, "flash:");
+  uint8_t mode =  get_param_int(argc, args, 1, FILE_READ);
+
+  File file;
+  char *namePtr;
+
+  if (strncmp(name, "flash:", 6) == 0) {
+    namePtr = (char *)name + 6;
+    file = flashfs.open(namePtr, mode);
+  } else if (strncmp(name, "sd:", 3) == 0) {
+    // root directory of SD must be "/", "" will crash
+    if (strlen(name) == 3) {
+      file = SD.open("/", mode);
+    } else {
+      namePtr = (char *)name + 3;
+      file = SD.open(namePtr, mode);
+    }
+  } else {
+    file = flashfs.open(name, mode);
+  }
+
+  if (!file) {
+    v_setint(retval, 0);
+    return 1;
+  }
+
+  fileStack.push_back(file);
+
+  map_init(retval);
+  retval->v.m.id = fileStack.size() - 1;
+  if (file.isDirectory()) {
+    v_create_callback(retval, "getNextFilename", cmd_getNextFilename);
+  } else {
+    if (mode == FILE_READ) {
+      v_create_callback(retval, "read", cmd_read);
+      v_create_callback(retval, "available", cmd_available);
+    } else if (mode == FILE_WRITE) {
+      v_create_callback(retval, "write", cmd_write);
+      v_create_callback(retval, "truncate", cmd_truncate);
+      v_create_callback(retval, "flush", cmd_flush);
+    }
+    v_create_callback(retval, "size", cmd_size);
+    v_create_callback(retval, "position", cmd_position);
+    v_create_callback(retval, "seek", cmd_seek);
+  }
+  v_create_callback(retval, "isDirectory", cmd_isDirectory);
+  v_create_callback(retval, "close", cmd_close);
+
+  return 1;
+}
+
+/*
+ * create directory
+ * mkdir(name) -> 'name' directory name
+ */
+
+static int cmd_mkdir(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  const char *name = get_param_str(argc, args, 0, "");
+  char *namePtr;
+
+  if (strncmp(name, "flash:", 6) == 0) {
+    namePtr = (char *)name + 6;
+    v_setint(retval, flashfs.mkdir(namePtr));
+    return 1;
+  }
+  if (strncmp(name, "sd:", 3) == 0) {
+    namePtr = (char *)name + 3;
+    v_setint(retval, SD.mkdir(namePtr));
+    return 1;
+  }
+
+  v_setint(retval, flashfs.mkdir(name));
+  return 1;
+}
+
+/*
+ * Quickformate flash memory
+ */
+static int cmd_quickFormat(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  v_setint(retval, flashfs.quickFormat());
+  return 1;
+}
+
+/*
+ * check if file or directory exists
+ * returns true or false
+ */
+static int cmd_exists(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  const char *name = get_param_str(argc, args, 0, "");
+  char *namePtr;
+
+  if (strncmp(name, "flash:", 6) == 0) {
+    namePtr = (char *)name + 6;
+    v_setint(retval, flashfs.exists(namePtr));
+    return 1;
+  }
+  if (strncmp(name, "sd:", 3) == 0) {
+    namePtr = (char *)name + 3;
+    v_setint(retval, SD.exists(namePtr));
+    return 1;
+  }
+
+  v_setint(retval, flashfs.exists(name));
+  return 1;
+}
+
+/*
+ * rename a file or directory
+ * rename(name_old, name_new) -> 'name_old' current name; 'name_new' new name
+ */
+static int cmd_rename(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  const char *nameOld = get_param_str(argc, args, 0, "");
+  const char *nameNew = get_param_str(argc, args, 1, "");
+  char *nameOldPtr;
+  char *nameNewPtr;
+
+  if (strncmp(nameOld, "flash:", 6) == 0 && strncmp(nameNew, "flash:", 6) == 0) {
+    nameOldPtr = (char *)nameOld + 6;
+    nameNewPtr = (char *)nameNew + 6;
+    v_setint(retval, flashfs.rename(nameOldPtr, nameNewPtr));
+    return 1;
+  }
+  if (strncmp(nameOld, "sd:", 3) == 0 && strncmp(nameNew, "sd:", 3) == 0) {
+    nameOldPtr = (char *)nameOld + 3;
+    nameNewPtr = (char *)nameNew + 3;
+    v_setint(retval, SD.rename(nameOldPtr, nameNewPtr));
+    return 1;
+  }
+
+  v_setint(retval, flashfs.rename(nameOld, nameNew));
+  return 1;
+}
+
+/*
+ * remove file or directory
+ * remove(name) -> 'name' file or directory
+ */
+static int cmd_remove(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  const char *name = get_param_str(argc, args, 0, "");
+  char *namePtr;
+
+  if (strncmp(name, "flash:", 6) == 0) {
+    namePtr = (char *)name + 6;
+    v_setint(retval, flashfs.remove(namePtr));
+    return 1;
+  }
+  if (strncmp(name, "sd:", 3) == 0) {
+    namePtr = (char *)name + 3;
+    v_setint(retval, SD.remove(namePtr));
+    return 1;
+  }
+
+  v_setint(retval, flashfs.remove(name));
+  return 1;
+}
+
+/*
+ * show file system usage
+ * returns an array [FlashUsedSize, FlashTotalSize, SDUsedSize, SDTotalSize]
+ */
+static int cmd_free(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  v_toarray1(retval, 4);
+  v_setint(v_elem(retval, 0), flashfs.usedSize());
+  v_setint(v_elem(retval, 1), flashfs.totalSize());
+  v_setint(v_elem(retval, 2), SD.usedSize());
+  v_setint(v_elem(retval, 3), SD.totalSize());
+  return 1;
+}
+
+int cmd_fs(int argc, slib_par_t *args, var_t *retval) {
+  map_init(retval);
+  v_create_callback(retval, "OPEN", cmd_open);
+  v_create_callback(retval, "QUICKFORMAT", cmd_quickFormat);
+  v_create_callback(retval, "EXISTS", cmd_exists);
+  v_create_callback(retval, "MKDIR", cmd_mkdir);
+  v_create_callback(retval, "RENAME", cmd_rename);
+  v_create_callback(retval, "REMOVE", cmd_remove);
+  v_create_callback(retval, "FREE", cmd_free);
+
+  return 1;
+}
+
+int fs_close(void) {
+  for(File& f : fileStack) {
+    if (f) {
+      f.close();
+    }
+  }
+  return 1;
+}
diff --git a/src/platform/teensy/src/fs.h b/src/platform/teensy/src/fs.h
new file mode 100644
index 00000000..86245fd1
--- /dev/null
+++ b/src/platform/teensy/src/fs.h
@@ -0,0 +1,15 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2001-2025 Chris Warren-Smith.
+// Copyright(C) 2000 Nicholas Christopoulos
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#pragma once
+
+#include "common/var.h"
+
+int cmd_fs(int argc, slib_par_t *args, var_t *retval);
+int fs_close(void);
diff --git a/src/platform/teensy/src/i2c.cpp b/src/platform/teensy/src/i2c.cpp
new file mode 100644
index 00000000..5bea6242
--- /dev/null
+++ b/src/platform/teensy/src/i2c.cpp
@@ -0,0 +1,154 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2026 Joerg Siebenmorgen
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#include <Arduino.h>
+#include "config.h"
+#include "languages/messages.en.h"
+#include "include/var_map.h"
+#include "module.h"
+#include <Wire.h>
+
+static TwoWire *getI2C(int interfaceNumber) {
+  TwoWire *result;
+  switch (interfaceNumber) {
+  case 0:
+    result = &Wire;
+    break;
+  case 1:
+    result = &Wire1;
+    break;
+  case 2:
+    result = &Wire2;
+    break;
+  default:
+    result = &Wire;
+    break;
+  }
+  return result;
+}
+
+static int cmd_i2c_write(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  uint8_t address = get_param_int(argc, args, 0, 0);
+  uint8_t stop = get_param_int(argc, args, 2, 1);
+
+  if (address == 0 || argc < 2) {
+    v_setstr(retval, ERR_PARAM);
+    return 0;
+  }
+
+  int interfaceNumber = self->v.m.id;
+  TwoWire *ptrWire;
+  ptrWire = getI2C(interfaceNumber);
+
+  ptrWire->beginTransmission(address);
+
+  switch (args[1].var_p->type) {
+  case V_INT:{
+      int value = get_param_int(argc, args, 1, 0);
+      ptrWire->write(value);
+    }
+    break;
+  case V_STR:{
+      const char *buffer = v_getstr(args[1].var_p);
+      int length = v_strlen(args[1].var_p);
+      ptrWire->write(buffer, length);
+    }
+    break;
+  case V_ARRAY:{
+      var_p_t array = args[1].var_p;    // Get array
+      if (array->maxdim > 1) {
+        v_setstr(retval, "ERROR: I2C: Write requires 1D-array");
+        return 0;
+      }
+      uint32_t bytes = v_ubound(array, 0) - v_lbound(array, 0) + 1;
+      uint8_t *buffer = new uint8_t[bytes];
+      for (uint32_t ii = 0; ii < bytes; ii++) {
+        buffer[ii] = get_array_elem_int(array, ii);
+      }
+      ptrWire->write(buffer, bytes);
+      delete[]buffer;
+    }
+    break;
+  }
+
+  if (ptrWire->endTransmission(stop)) {
+    v_setstr(retval, "ERROR I2C: Transmission failed");
+    return 0;
+  }
+
+  return 1;
+}
+
+static int cmd_i2c_read(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  uint8_t address = get_param_int(argc, args, 0, 0);
+  uint32_t bytes = get_param_int(argc, args, 1, 1);
+  uint8_t stop = get_param_int(argc, args, 2, 1);
+
+  if (address == 0) {
+    v_setstr(retval, ERR_PARAM);
+    return 0;
+  }
+
+  int interfaceNumber = self->v.m.id;
+  TwoWire *ptrWire;
+  ptrWire = getI2C(interfaceNumber);
+  ptrWire->requestFrom(address, bytes, stop);
+
+  if (bytes > 1) {
+    v_toarray1(retval, bytes);
+    for (uint32_t ii = 0; ii < bytes; ii++) {
+      v_setint(v_elem(retval, ii), ptrWire->read());
+    }
+  } else {
+    v_setint(retval, ptrWire->read());
+  }
+  return 1;
+}
+
+static int cmd_i2c_setClock(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  uint32_t clockFrequency = get_param_int(argc, args, 0, 100000);
+
+  if (clockFrequency != 100000 && clockFrequency != 400000 && clockFrequency != 1000000) {
+    v_setstr(retval, "ERROR I2C: Clock freuqency not supported");
+    return 0;
+  }
+
+  int interfaceNumber = self->v.m.id;
+  getI2C(interfaceNumber)->setClock(clockFrequency);
+
+  return 1;
+}
+
+int cmd_openi2c(int argc, slib_par_t *args, var_t *retval) {
+  uint8_t interfaceNumber = get_param_int(argc, args, 0, 0);
+  uint8_t pinSDA = get_param_int(argc, args, 1, 0);
+  uint8_t pinSCL = get_param_int(argc, args, 2, 0);
+
+  if (interfaceNumber > 2) {
+    v_setstr(retval, ERR_PARAM);
+    return 0;
+  }
+
+  map_init(retval);
+  v_create_callback(retval, "write", cmd_i2c_write);
+  v_create_callback(retval, "read", cmd_i2c_read);
+  v_create_callback(retval, "setClock", cmd_i2c_setClock);
+  retval->v.m.id = interfaceNumber;
+
+  TwoWire *ptrWire;
+  ptrWire = getI2C(interfaceNumber);
+
+  if (pinSDA > 0 && pinSCL > 0) {
+    ptrWire->setSDA(pinSDA);
+    ptrWire->setSCL(pinSCL);
+  }
+
+  ptrWire->begin();
+
+  return 1;
+}
diff --git a/src/platform/teensy/src/i2c.h b/src/platform/teensy/src/i2c.h
new file mode 100644
index 00000000..64734cfc
--- /dev/null
+++ b/src/platform/teensy/src/i2c.h
@@ -0,0 +1,14 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2001-2025 Chris Warren-Smith.
+// Copyright(C) 2000 Nicholas Christopoulos
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#pragma once
+
+#include "common/var.h"
+
+int cmd_openi2c(int argc, slib_par_t *args, var_t *retval);
diff --git a/src/platform/teensy/src/main.cpp b/src/platform/teensy/src/main.cpp
index dbc86413..30f5ae1e 100644
--- a/src/platform/teensy/src/main.cpp
+++ b/src/platform/teensy/src/main.cpp
@@ -10,6 +10,7 @@
 #include <Arduino.h>
 #include <SPI.h>
 #include <SD.h>
+#include <LittleFS.h>
 #include "common/device.h"
 #include "config.h"
 #include "common/sbapp.h"
@@ -19,8 +20,10 @@
 
 #define MAIN_BAS "__main_bas__"
 #define SERIAL_SD_BAS "__serial_sd_bas__"
+#define PROG_FLASH_SIZE 65536*16
 
 strlib::String buffer;
+LittleFS_Program flashfs;
 
 void *plugin_lib_open(const char *name) {
   void *result = nullptr;
@@ -50,6 +53,8 @@ void *plugin_lib_address(void *handle, const char *name) {
     result = (void *)pModule->_func_count;
   } else if (strcmp(name, "sblib_func_getname") == 0) {
     result = (void *)pModule->_func_getname;
+  } else if (strcmp(name, "sblib_close") == 0) {
+    result = (void *)pModule->_close;
   }
   return result;
 }
@@ -93,6 +98,13 @@ void setup() {
   opt_verbose = 0;
   opt_graphics = 0;
   dev_init(0, 0);
+
+  if (!flashfs.begin(PROG_FLASH_SIZE)) {
+    while (1) {
+      dev_print("Error initializing FLASH file system\n");
+      delay(1000);
+    }
+  }
 }
 
 void serial_read() {
@@ -171,7 +183,7 @@ void print_error(char *source) {
 
 void interactive_main() {
   while (true) {
-    dev_print("\r\n\033[30;47mInteractive mode - waiting for data...\033[0m\r\n");
+    dev_print("\r\nWaiting for upload... ");
     serial_read();
     if (!sbasic_main(SERIAL_SD_BAS)) {
       print_error((char *)buffer.c_str());
@@ -179,34 +191,53 @@ void interactive_main() {
   }
 }
 
+void executeFile(File *f) {
+  uint32_t fileSize = f->available();
+  char *fileBuffer = new char[fileSize + 1];
+
+  f->read(fileBuffer, fileSize);
+  fileBuffer[fileSize] = '\0';
+  buffer.clear();
+  buffer.append(fileBuffer);
+
+  delete[]fileBuffer;
+
+  if (!sbasic_main(SERIAL_SD_BAS)) {
+    while (!Serial) {
+      delay(250);
+    }
+    dev_print("Error executing MAIN.BAS:\n");
+    print_error((char *)buffer.c_str());
+  } else {
+    dev_print("MAIN.BAS ended\n");
+  }
+}
+
 extern "C" int main(void) {
   setup();
 
+  // Start from SD card
   if (SD.begin(BUILTIN_SDCARD)) {
     File sdFile = SD.open("/MAIN.BAS", FILE_READ);
     if (sdFile) {
-      uint32_t fileSize = sdFile.available();
-      char *bufferSD = new char[fileSize + 1];
-
-      sdFile.read(bufferSD, fileSize);
-      bufferSD[fileSize] = '\0';
-      buffer.clear();
-      buffer.append(bufferSD);
-
-      delete[]bufferSD;
+      executeFile(&sdFile);
       sdFile.close();
+      goto interactive;
+    }
+  }
 
-      if (!sbasic_main(SERIAL_SD_BAS)) {
-        while (!Serial) {
-          delay(250);
-        }
-        dev_print("Error executing main.bas from SD card:\n");
-        print_error((char *)buffer.c_str());
-      } else {
-        dev_print("main.bas from SD card ended\n");
-      }
+  // Start from LittleFS
+  if (flashfs.exists("/MAIN.BAS")) {
+    File flashFile = flashfs.open("/MAIN.BAS", FILE_READ);
+    if (flashFile) {
+      executeFile(&flashFile);
+      flashFile.close();
+      goto interactive;
     }
-  } else if (main_bas_len > 0) {
+  }
+
+  // Start from memory
+  if (main_bas_len > 0) {
     if (!sbasic_main(MAIN_BAS)) {
       while (!Serial) {
         delay(250);
@@ -216,7 +247,8 @@ extern "C" int main(void) {
     } else {
       dev_print("main.bas ended");
     }
-  } else {
-    interactive_main();
   }
+
+interactive:
+  interactive_main();
 }
diff --git a/src/platform/teensy/src/module.h b/src/platform/teensy/src/module.h
index 07812fa7..f5a95f40 100644
--- a/src/platform/teensy/src/module.h
+++ b/src/platform/teensy/src/module.h
@@ -45,6 +45,7 @@ typedef struct {
   sblib_count_fn _proc_count;
   sblib_getname_fn _proc_getname;
   sblib_free_fn _free;
+  sblib_close_fn _close;
 } ModuleConfig;
 
 ModuleConfig *get_teensy_module();
diff --git a/src/platform/teensy/src/pinio.cpp b/src/platform/teensy/src/pinio.cpp
new file mode 100644
index 00000000..1135bee7
--- /dev/null
+++ b/src/platform/teensy/src/pinio.cpp
@@ -0,0 +1,158 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2026 Joerg Siebenmorgen
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#include <Arduino.h>
+#include "config.h"
+#include "languages/messages.en.h"
+#include "include/var_map.h"
+#include "module.h"
+
+static void set_pin(var_p_t var, uint8_t pin, uint8_t mode) {
+  map_init(var);
+  var->v.m.id = pin;
+  pinMode(pin, mode);
+}
+
+static bool is_pin(int id) {
+  return id >= 0 && id < CORE_NUM_TOTAL_PINS;
+}
+
+static bool is_pin_object(var_p_t var) {
+  return var != nullptr && v_is_type(var, V_MAP) && is_pin(var->v.m.id);
+}
+
+static int cmd_analoginput_read(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
+  int result = 0;
+  if (argc != 0 || !is_pin_object(self)) {
+    error(retval, "AnalogInput.read", 0);
+  } else {
+    int pin = self->v.m.id;
+    v_setint(retval, analogRead(pin));
+    result = 1;
+  }
+  return result;
+}
+
+int cmd_openanaloginput(int argc, slib_par_t *args, var_t *retval) {
+  int result = 1;
+  int pin = get_param_int(argc, args, 0, -1);
+  if (is_pin(pin)) {
+    set_pin(retval, pin, INPUT);
+    v_create_callback(retval, "read", cmd_analoginput_read);
+  } else {
+    result = 0;
+  }
+  return result;
+}
+
+static int cmd_digitalinput_read(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
+  int result = 0;
+  if (argc != 0 || !is_pin_object(self)) {
+    error(retval, "DigitalInput.read", 0);
+  } else {
+    int pin = self->v.m.id;
+    v_setint(retval, digitalRead(pin));
+    result = 1;
+  }
+  return result;
+}
+
+int cmd_opendigitalinput(int argc, slib_par_t *args, var_t *retval) {
+  int result = 1;
+  int pin = get_param_int(argc, args, 0, -1);
+  uint8_t mode = get_param_int(argc, args, 1, 1);
+  if (mode) {
+    mode = INPUT_PULLUP;
+  } else {
+    mode = INPUT;
+  }
+  if (is_pin(pin)) {
+    set_pin(retval, pin, mode);
+    v_create_callback(retval, "read", cmd_digitalinput_read);
+    result = 1;
+  } else {
+    result = 0;
+  }
+  return result;
+}
+
+static int cmd_digitaloutput_write(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
+  int result = 0;
+  if (argc != 1 || !is_pin_object(self)) {
+    error(retval, "DigitalOutput.write", 1);
+  } else {
+    int pin = self->v.m.id;
+    int value = get_param_int(argc, arg, 0, 0);
+    digitalWrite(pin, value);
+    result = 1;
+  }
+  return result;
+}
+
+int cmd_opendigitaloutput(int argc, slib_par_t *args, var_t *retval) {
+  int result;
+  int pin = get_param_int(argc, args, 0, -1);
+  if (is_pin(pin)) {
+    set_pin(retval, pin, OUTPUT);
+    v_create_callback(retval, "write", cmd_digitaloutput_write);
+    result = 1;
+  } else {
+    result = 0;
+  }
+  return result;
+}
+
+static int cmd_analogoutput_write(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
+  if (argc != 1 || !is_pin_object(self)) {
+    error(retval, "AnalogOutput.write", 1);
+    return 0;
+  } else {
+    int pin = self->v.m.id;
+    int value = get_param_int(argc, arg, 0, 0);
+    analogWrite(pin, value);
+  }
+  return 1;
+}
+
+static int cmd_analogoutput_frequency(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
+  if (argc != 1 || !is_pin_object(self)) {
+    error(retval, "AnalogOutput.frequency", 1);
+    return 0;
+  } else {
+    int pin = self->v.m.id;
+    double value = get_param_num(argc, arg, 0, 0.0);
+    analogWriteFrequency(pin, value);
+  }
+  return 1;
+}
+
+static int cmd_analogoutput_resolution(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
+  if (argc != 1 || !is_pin_object(self)) {
+    error(retval, "AnalogOutput.resolution", 1);
+    return 0;
+  } else {
+    int value = get_param_int(argc, arg, 0, 0);
+    analogWriteResolution(value);
+  }
+  return 1;
+}
+
+int cmd_openanalogoutput(int argc, slib_par_t *args, var_t *retval) {
+  int result;
+  int pin = get_param_int(argc, args, 0, -1);
+  if (is_pin(pin)) {
+    set_pin(retval, pin, OUTPUT);
+    v_create_callback(retval, "write", cmd_analogoutput_write);
+    v_create_callback(retval, "frequency", cmd_analogoutput_frequency);
+    v_create_callback(retval, "resolution", cmd_analogoutput_resolution);
+    result = 1;
+  } else {
+    result = 0;
+  }
+  return result;
+}
diff --git a/src/platform/teensy/src/pinio.h b/src/platform/teensy/src/pinio.h
new file mode 100644
index 00000000..882607d2
--- /dev/null
+++ b/src/platform/teensy/src/pinio.h
@@ -0,0 +1,17 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2001-2025 Chris Warren-Smith.
+// Copyright(C) 2000 Nicholas Christopoulos
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#pragma once
+
+#include "common/var.h"
+
+int cmd_opendigitalinput(int argc, slib_par_t *args, var_t *retval);
+int cmd_opendigitaloutput(int argc, slib_par_t *args, var_t *retval);
+int cmd_openanaloginput(int argc, slib_par_t *args, var_t *retval);
+int cmd_openanalogoutput(int argc, slib_par_t *args, var_t *retval);
diff --git a/src/platform/teensy/src/serial.cpp b/src/platform/teensy/src/serial.cpp
new file mode 100644
index 00000000..277738ee
--- /dev/null
+++ b/src/platform/teensy/src/serial.cpp
@@ -0,0 +1,172 @@
+// This file is part of SmallBASIC
+//
+// Copyright(C) 2026 Joerg Siebenmorgen
+//
+// This program is distributed under the terms of the GPL v2.0 or later
+// Download the GNU Public License (GPL) from www.gnu.org
+//
+
+#include <Arduino.h>
+#include "config.h"
+#include "languages/messages.en.h"
+#include "include/var_map.h"
+#include "module.h"
+#include "serial.h"
+
+#define USB_CLASS_ID 1002
+#define MAX_HW_SERIAL 7
+#define SERIAL_DEFAULT_BAUD 9600
+
+static HardwareSerialIMXRT *getSerial(int serialNo) {
+  HardwareSerialIMXRT *result;
+  switch (serialNo) {
+  case 1:
+    result = &Serial1;
+    break;
+  case 2:
+    result = &Serial2;
+    break;
+  case 3:
+    result = &Serial3;
+    break;
+  case 4:
+    result = &Serial4;
+    break;
+  case 5:
+    result = &Serial5;
+    break;
+  case 6:
+    result = &Serial6;
+    break;
+  case 7:
+    result = &Serial7;
+    break;
+  default:
+    result = &Serial1;
+    break;
+  }
+  return result;
+}
+
+static bool is_serial(int id) {
+  return id >= 0 && id <= MAX_HW_SERIAL;
+}
+
+static bool is_serial_var(var_p_t var) {
+  return var != nullptr && v_is_type(var, V_INT) && is_serial(var->v.i);
+}
+
+static bool is_serial_object(var_p_t var) {
+  return var != nullptr && v_is_type(var, V_MAP) && is_serial(var->v.m.id);
+}
+
+static int cmd_serial_ready(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  int result;
+  if (argc != 0 || !is_serial_object(self)) {
+    v_setstr(retval, ERR_PARAM);
+    result = 0;
+  } else {
+    int serialNo = self->v.m.id;
+    if (serialNo == 0) {
+      v_setint(retval, Serial.available());
+    } else {
+      v_setint(retval, getSerial(serialNo)->available());
+    }
+    result = 1;
+  }
+  return result;
+}
+
+static int cmd_serial_receive(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  int result;
+  if (argc > 1 || !is_serial_object(self)) {
+    v_setstr(retval, ERR_PARAM);
+    result = 0;
+  } else {
+    int bufferSize = get_param_int(argc, args, 0, 0);
+    int size;
+    int serialNo = self->v.m.id;
+
+    if (bufferSize == 0) {
+      // Read until '\n' and return as string
+      bufferSize = CDC_RX_SIZE_480;
+      char buffer[bufferSize];
+
+      if (serialNo == 0) {
+        size = Serial.readBytesUntil('\n', buffer, bufferSize - 1);
+      } else {
+        size = getSerial(serialNo)->readBytesUntil('\n', buffer, bufferSize - 1);
+      }
+      buffer[size] = '\0';
+      v_setstr(retval, buffer);
+      result = 1;
+    } else {
+      // Read number of bytes and return as array
+      char buffer[bufferSize];
+      if (serialNo == 0) {
+        size = Serial.readBytes(buffer, bufferSize);
+      } else {
+        size = getSerial(serialNo)->readBytes(buffer, bufferSize);
+      }
+      if (bufferSize > 1) {
+        v_toarray1(retval, bufferSize);
+        for (int32_t ii = 0; ii < size; ii++) {
+          v_setint(v_elem(retval, ii), buffer[ii]);
+        }
+      } else {
+        v_setint(retval, buffer[0]);
+      }
+      result = 1;
+    }
+  }
+  return result;
+}
+
+static int cmd_serial_send(var_s *self, int argc, slib_par_t *args, var_s *retval) {
+  int result;
+  if (argc != 1 || !is_serial_object(self) || !v_is_type(args[0].var_p, V_STR)) {
+    v_setstr(retval, ERR_PARAM);
+    result = 0;
+  } else {
+    const char *buffer = v_getstr(args[0].var_p);
+    int length = v_strlen(args[0].var_p);
+    int serialNo = self->v.m.id;
+    switch (serialNo) {
+    case 0:
+      Serial.write(buffer, length);
+      break;
+    default:
+      getSerial(serialNo)->write(buffer, length);
+      break;
+    }
+    result = 1;
+  }
+  return result;
+}
+
+int cmd_openserial(int argc, slib_par_t *args, var_t *retval) {
+  int result;
+  if (!(argc == 0 || (argc == 1 && is_serial_var(args[0].var_p)))) {
+    v_setstr(retval, ERR_PARAM);
+    result = 0;
+  } else {
+    int serialNo = argc == 0 ? 0 : args[0].var_p->v.i;
+    map_init(retval);
+    retval->v.m.id = serialNo;
+    retval->v.m.cls_id = USB_CLASS_ID;
+    v_create_callback(retval, "ready", cmd_serial_ready);
+    v_create_callback(retval, "receive", cmd_serial_receive);
+    v_create_callback(retval, "send", cmd_serial_send);
+    switch (serialNo) {
+    case 0:
+      serial_init();
+      break;
+    default:
+      int serialSpeed = get_param_int(argc, args, 1, SERIAL_DEFAULT_BAUD);
+      getSerial(serialNo)->begin(serialSpeed);
+      break;
+    }
+    result = 1;
+  }
+  return result;
+}
\ No newline at end of file
diff --git a/src/platform/teensy/src/serial.h b/src/platform/teensy/src/serial.h
index 0c854b87..d887ab01 100644
--- a/src/platform/teensy/src/serial.h
+++ b/src/platform/teensy/src/serial.h
@@ -9,4 +9,7 @@
 
 #pragma once
 
+#include "common/var.h"
+
 void serial_init();
+int cmd_openserial(int argc, slib_par_t *args, var_t *retval);
diff --git a/src/platform/teensy/src/ssd1306.cpp b/src/platform/teensy/src/ssd1306.cpp
index 28639418..4c21f335 100644
--- a/src/platform/teensy/src/ssd1306.cpp
+++ b/src/platform/teensy/src/ssd1306.cpp
@@ -393,7 +393,8 @@ static ModuleConfig ssd1306Module = {
   ._proc_exec = ssd1306_proc_exec,
   ._proc_count = ssd1306_proc_count,
   ._proc_getname = ssd1306_proc_getname,
-  ._free = nullptr
+  ._free = nullptr,
+  ._close = nullptr
 };
 
 ModuleConfig *get_ssd1306_module() {
diff --git a/src/platform/teensy/src/teensy.cpp b/src/platform/teensy/src/teensy.cpp
index 72b0d13b..5a026a68 100644
--- a/src/platform/teensy/src/teensy.cpp
+++ b/src/platform/teensy/src/teensy.cpp
@@ -16,220 +16,12 @@
 #include "device.h"
 #include "module.h"
 #include "serial.h"
+#include "i2c.h"
+#include "pinio.h"
+#include "fs.h"
 #include <Wire.h>
 #include <malloc.h>
 
-#define USB_CLASS_ID 1002
-#define MAX_HW_SERIAL 7
-#define BT_BAUD 9600
-
-static HardwareSerialIMXRT *getSerial(int serialNo) {
-  HardwareSerialIMXRT *result;
-  switch (serialNo) {
-  case 1:
-    result = &Serial1;
-    break;
-  case 2:
-    result = &Serial2;
-    break;
-  case 3:
-    result = &Serial3;
-    break;
-  case 4:
-    result = &Serial4;
-    break;
-  case 5:
-    result = &Serial5;
-    break;
-  case 6:
-    result = &Serial6;
-    break;
-  case 7:
-    result = &Serial7;
-    break;
-  default:
-    result = &Serial1;
-    break;
-  }
-  return result;
-}
-
-static TwoWire *getI2C(int interfaceNumber) {
-  TwoWire *result;
-  switch (interfaceNumber) {
-  case 0:
-    result = &Wire;
-    break;
-  case 1:
-    result = &Wire1;
-    break;
-  case 2:
-    result = &Wire2;
-    break;
-  default:
-    result = &Wire;
-    break;
-  }
-  return result;
-}
-
-static void set_pin(var_p_t var, uint8_t pin, uint8_t mode) {
-  map_init(var);
-  var->v.m.id = pin;
-  pinMode(pin, mode);
-}
-
-static bool is_pin(int id) {
-  return id >= 0 && id < CORE_NUM_TOTAL_PINS;
-}
-
-static bool is_pin_object(var_p_t var) {
-  return var != nullptr && v_is_type(var, V_MAP) && is_pin(var->v.m.id);
-}
-
-static bool is_serial(int id) {
-  return id >= 0 && id <= MAX_HW_SERIAL;
-}
-
-static bool is_serial_var(var_p_t var) {
-  return var != nullptr && v_is_type(var, V_INT) && is_serial(var->v.i);
-}
-
-static bool is_serial_object(var_p_t var) {
-  return var != nullptr && v_is_type(var, V_MAP) && is_serial(var->v.m.id);
-}
-
-static int cmd_analoginput_read(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
-  int result = 0;
-  if (argc != 0 || !is_pin_object(self)) {
-    error(retval, "AnalogInput.read", 0);
-  } else {
-    int pin = self->v.m.id;
-    v_setint(retval, analogRead(pin));
-    result = 1;
-  }
-  return result;
-}
-
-static int cmd_openanaloginput(int argc, slib_par_t *args, var_t *retval) {
-  int result = 1;
-  int pin = get_param_int(argc, args, 0, -1);
-  if (is_pin(pin)) {
-    set_pin(retval, pin, INPUT);
-    v_create_callback(retval, "read", cmd_analoginput_read);
-  } else {
-    result = 0;
-  }
-  return result;
-}
-
-static int cmd_digitalinput_read(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
-  int result = 0;
-  if (argc != 0 || !is_pin_object(self)) {
-    error(retval, "DigitalInput.read", 0);
-  } else {
-    int pin = self->v.m.id;
-    v_setint(retval, digitalRead(pin));
-    result = 1;
-  }
-  return result;
-}
-
-static int cmd_opendigitalinput(int argc, slib_par_t *args, var_t *retval) {
-  int result = 1;
-  int pin = get_param_int(argc, args, 0, -1);
-  uint8_t mode = get_param_int(argc, args, 1, 1);
-  if (mode) {
-    mode = INPUT_PULLUP;
-  } else {
-    mode = INPUT;
-  }
-  if (is_pin(pin)) {
-    set_pin(retval, pin, mode);
-    v_create_callback(retval, "read", cmd_digitalinput_read);
-    result = 1;
-  } else {
-    result = 0;
-  }
-  return result;
-}
-
-static int cmd_digitaloutput_write(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
-  int result = 0;
-  if (argc != 1 || !is_pin_object(self)) {
-    error(retval, "DigitalOutput.write", 1);
-  } else {
-    int pin = self->v.m.id;
-    int value = get_param_int(argc, arg, 0, 0);
-    digitalWrite(pin, value);
-    result = 1;
-  }
-  return result;
-}
-
-static int cmd_opendigitaloutput(int argc, slib_par_t *args, var_t *retval) {
-  int result;
-  int pin = get_param_int(argc, args, 0, -1);
-  if (is_pin(pin)) {
-    set_pin(retval, pin, OUTPUT);
-    v_create_callback(retval, "write", cmd_digitaloutput_write);
-    result = 1;
-  } else {
-    result = 0;
-  }
-  return result;
-}
-
-static int cmd_analogoutput_write(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
-  if (argc != 1 || !is_pin_object(self)) {
-    error(retval, "AnalogOutput.write", 1);
-    return 0;
-  } else {
-    int pin = self->v.m.id;
-    int value = get_param_int(argc, arg, 0, 0);
-    analogWrite(pin, value);
-  }
-  return 1;
-}
-
-static int cmd_analogoutput_frequency(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
-  if (argc != 1 || !is_pin_object(self)) {
-    error(retval, "AnalogOutput.frequency", 1);
-    return 0;
-  } else {
-    int pin = self->v.m.id;
-    double value = get_param_num(argc, arg, 0, 0.0);
-    analogWriteFrequency(pin, value);
-  }
-  return 1;
-}
-
-static int cmd_analogoutput_resolution(var_s *self, int argc, slib_par_t *arg, var_s *retval) {
-  if (argc != 1 || !is_pin_object(self)) {
-    error(retval, "AnalogOutput.resolution", 1);
-    return 0;
-  } else {
-    int value = get_param_int(argc, arg, 0, 0);
-    analogWriteResolution(value);
-  }
-  return 1;
-}
-
-static int cmd_openanalogoutput(int argc, slib_par_t *args, var_t *retval) {
-  int result;
-  int pin = get_param_int(argc, args, 0, -1);
-  if (is_pin(pin)) {
-    set_pin(retval, pin, OUTPUT);
-    v_create_callback(retval, "write", cmd_analogoutput_write);
-    v_create_callback(retval, "frequency", cmd_analogoutput_frequency);
-    v_create_callback(retval, "resolution", cmd_analogoutput_resolution);
-    result = 1;
-  } else {
-    result = 0;
-  }
-  return result;
-}
-
 static int cmd_get_temperature(int argc, slib_par_t *args, var_t *retval) {
   v_setint(retval, tempmonGetTemp());
   return 1;
@@ -240,238 +32,6 @@ static int cmd_get_cpu_speed(int argc, slib_par_t *args, var_t *retval) {
   return 1;
 }
 
-static int cmd_serial_ready(var_s *self, int argc, slib_par_t *args, var_s *retval) {
-  int result;
-  if (argc != 0 || !is_serial_object(self)) {
-    v_setstr(retval, ERR_PARAM);
-    result = 0;
-  } else {
-    int serialNo = self->v.m.id;
-    if (serialNo == 0) {
-      v_setint(retval, Serial.available());
-    } else {
-      v_setint(retval, getSerial(serialNo)->available());
-    }
-    result = 1;
-  }
-  return result;
-}
-
-static int cmd_serial_receive(var_s *self, int argc, slib_par_t *args, var_s *retval) {
-  int result;
-  if (argc > 1 || !is_serial_object(self)) {
-    v_setstr(retval, ERR_PARAM);
-    result = 0;
-  } else {
-    int bufferSize = get_param_int(argc, args, 0, 0);
-    int size;
-    int serialNo = self->v.m.id;
-
-    if (bufferSize == 0) {
-      // Read until '\n' and return as string
-      bufferSize = CDC_RX_SIZE_480;
-      char buffer[bufferSize];
-
-      if (serialNo == 0) {
-        size = Serial.readBytesUntil('\n', buffer, bufferSize - 1);
-      } else {
-        size = getSerial(serialNo)->readBytesUntil('\n', buffer, bufferSize - 1);
-      }
-      buffer[size] = '\0';
-      v_setstr(retval, buffer);
-      result = 1;
-    } else {
-      // Read number of bytes and return as array
-      char buffer[bufferSize];
-      if (serialNo == 0) {
-        size = Serial.readBytes(buffer, bufferSize);
-      } else {
-        size = getSerial(serialNo)->readBytes(buffer, bufferSize);
-      }
-      if (bufferSize > 1) {
-        v_toarray1(retval, bufferSize);
-        for (int32_t ii = 0; ii < size; ii++) {
-          v_setint(v_elem(retval, ii), buffer[ii]);
-        }
-      } else {
-        v_setint(retval, buffer[0]);
-      }
-      result = 1;
-    }
-  }
-  return result;
-}
-
-static int cmd_serial_send(var_s *self, int argc, slib_par_t *args, var_s *retval) {
-  int result;
-  if (argc != 1 || !is_serial_object(self) || !v_is_type(args[0].var_p, V_STR)) {
-    v_setstr(retval, ERR_PARAM);
-    result = 0;
-  } else {
-    const char *buffer = v_getstr(args[0].var_p);
-    int length = v_strlen(args[0].var_p);
-    int serialNo = self->v.m.id;
-    switch (serialNo) {
-    case 0:
-      Serial.write(buffer, length);
-      break;
-    default:
-      getSerial(serialNo)->write(buffer, length);
-      break;
-    }
-    result = 1;
-  }
-  return result;
-}
-
-static int cmd_openserial(int argc, slib_par_t *args, var_t *retval) {
-  int result;
-  if (!(argc == 0 || (argc == 1 && is_serial_var(args[0].var_p)))) {
-    v_setstr(retval, ERR_PARAM);
-    result = 0;
-  } else {
-    int serialNo = argc == 0 ? 0 : args[0].var_p->v.i;
-    map_init(retval);
-    retval->v.m.id = serialNo;
-    retval->v.m.cls_id = USB_CLASS_ID;
-    v_create_callback(retval, "ready", cmd_serial_ready);
-    v_create_callback(retval, "receive", cmd_serial_receive);
-    v_create_callback(retval, "send", cmd_serial_send);
-    switch (serialNo) {
-    case 0:
-      serial_init();
-      break;
-    default:
-      int serialSpeed = get_param_int(argc, args, 1, BT_BAUD);
-      getSerial(serialNo)->begin(serialSpeed);
-      break;
-    }
-    result = 1;
-  }
-  return result;
-}
-
-static int cmd_i2c_write(var_s *self, int argc, slib_par_t *args, var_s *retval) {
-  uint8_t address = get_param_int(argc, args, 0, 0);
-  uint8_t stop = get_param_int(argc, args, 2, 1);
-
-  if (address == 0 || argc < 2) {
-    v_setstr(retval, ERR_PARAM);
-    return 0;
-  }
-
-  int interfaceNumber = self->v.m.id;
-  TwoWire *ptrWire;
-  ptrWire = getI2C(interfaceNumber);
-
-  ptrWire->beginTransmission(address);
-
-  switch (args[1].var_p->type) {
-  case V_INT:{
-      int value = get_param_int(argc, args, 1, 0);
-      ptrWire->write(value);
-    }
-    break;
-  case V_STR:{
-      const char *buffer = v_getstr(args[1].var_p);
-      int length = v_strlen(args[1].var_p);
-      ptrWire->write(buffer, length);
-    }
-    break;
-  case V_ARRAY:{
-      var_p_t array = args[1].var_p;    // Get array
-      if (array->maxdim > 1) {
-        v_setstr(retval, "ERROR: I2C: Write requires 1D-array");
-        return 0;
-      }
-      uint32_t bytes = v_ubound(array, 0) - v_lbound(array, 0) + 1;
-      uint8_t *buffer = new uint8_t[bytes];
-      for (uint32_t ii = 0; ii < bytes; ii++) {
-        buffer[ii] = get_array_elem_int(array, ii);
-      }
-      ptrWire->write(buffer, bytes);
-      delete[]buffer;
-    }
-    break;
-  }
-
-  if (ptrWire->endTransmission(stop)) {
-    v_setstr(retval, "ERROR I2C: Transmission failed");
-    return 0;
-  }
-
-  return 1;
-}
-
-static int cmd_i2c_read(var_s *self, int argc, slib_par_t *args, var_s *retval) {
-  uint8_t address = get_param_int(argc, args, 0, 0);
-  uint32_t bytes = get_param_int(argc, args, 1, 1);
-  uint8_t stop = get_param_int(argc, args, 2, 1);
-
-  if (address == 0) {
-    v_setstr(retval, ERR_PARAM);
-    return 0;
-  }
-
-  int interfaceNumber = self->v.m.id;
-  TwoWire *ptrWire;
-  ptrWire = getI2C(interfaceNumber);
-  ptrWire->requestFrom(address, bytes, stop);
-
-  if (bytes > 1) {
-    v_toarray1(retval, bytes);
-    for (uint32_t ii = 0; ii < bytes; ii++) {
-      v_setint(v_elem(retval, ii), ptrWire->read());
-    }
-  } else {
-    v_setint(retval, ptrWire->read());
-  }
-  return 1;
-}
-
-static int cmd_i2c_setClock(var_s *self, int argc, slib_par_t *args, var_s *retval) {
-  uint32_t clockFrequency = get_param_int(argc, args, 0, 100000);
-
-  if (clockFrequency != 100000 && clockFrequency != 400000 && clockFrequency != 1000000) {
-    v_setstr(retval, "ERROR I2C: Clock freuqency not supported");
-    return 0;
-  }
-
-  int interfaceNumber = self->v.m.id;
-  getI2C(interfaceNumber)->setClock(clockFrequency);
-
-  return 1;
-}
-
-static int cmd_openi2c(int argc, slib_par_t *args, var_t *retval) {
-  uint8_t interfaceNumber = get_param_int(argc, args, 0, 0);
-  uint8_t pinSDA = get_param_int(argc, args, 1, 0);
-  uint8_t pinSCL = get_param_int(argc, args, 2, 0);
-
-  if (interfaceNumber > 2) {
-    v_setstr(retval, ERR_PARAM);
-    return 0;
-  }
-
-  map_init(retval);
-  v_create_callback(retval, "write", cmd_i2c_write);
-  v_create_callback(retval, "read", cmd_i2c_read);
-  v_create_callback(retval, "setClock", cmd_i2c_setClock);
-  retval->v.m.id = interfaceNumber;
-
-  TwoWire *ptrWire;
-  ptrWire = getI2C(interfaceNumber);
-
-  if (pinSDA > 0 && pinSCL > 0) {
-    ptrWire->setSDA(pinSDA);
-    ptrWire->setSCL(pinSCL);
-  }
-
-  ptrWire->begin();
-
-  return 1;
-}
-
 static int cmd_set_interactive(int argc, slib_par_t *args, var_t *retval) {
   uint8_t mode = get_param_int(argc, args, 0, 1);
 
@@ -505,6 +65,7 @@ static FuncSpec lib_func[] = {
   {1, 1, "OPENDIGITALOUTPUT", cmd_opendigitaloutput},
   {0, 1, "OPENSERIAL", cmd_openserial},
   {0, 3, "OPENI2C", cmd_openi2c},
+  {0, 0, "FS", cmd_fs},
   {0, 0, "FREE", cmd_free}
 };
 
@@ -582,6 +143,10 @@ static int teensy_proc_exec(int index, int argc, slib_par_t *args, var_t *retval
   return result;
 }
 
+void teensy_close(void) {
+  fs_close();
+}
+
 static ModuleConfig teensyModule = {
   ._func_exec = teensy_func_exec,
   ._func_count = teensy_func_count,
@@ -589,7 +154,8 @@ static ModuleConfig teensyModule = {
   ._proc_exec = teensy_proc_exec,
   ._proc_count = teensy_proc_count,
   ._proc_getname = teensy_proc_getname,
-  ._free = nullptr
+  ._free = nullptr,
+  ._close = teensy_close
 };
 
 ModuleConfig *get_teensy_module() {