TEENSY: Add flash and SD card file system

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

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) {

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

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
 

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
 

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})