Guide Arduino

Arduino IDE / PlatformIO

For 32-bit Arduino cores with about 64 KB of free RAM: ESP32 (every variant), RP2040 / RP2350 (Arduino-Pico or Mbed), nRF52840, SAMD51, STM32duino, Teensy, Portenta. AVR boards (UNO, Mega) are too small.

Arduino IDE

1. Get the library

Either download MicroCS-<version>.zip from the latest release, or build the package yourself (lets you bake in options, see step 4):

git clone https://github.com/amir1387aht/MicroCS && cd MicroCS
python3 tools/make_arduino.py            # -> dist/arduino/MicroCS-<version>.zip

In the IDE: Sketch → Include Library → Add .ZIP Library… and pick the zip.

2. Open the REPL example

File → Examples → MicroCS → MicroCS_REPL. It turns the board into a complete MicroCS device: C# prompt on Serial, files in the flash, /main.cs at start-up, MicroCS Studio and mcs_remote.py support.

Board settings that matter:

• ESP32: Tools → Partition Scheme with a SPIFFS/LittleFS part (the default has one).
• RP2040 / RP2350 (Arduino-Pico): Tools → Flash Size with an FS part, e.g. "2MB (Sketch: 1MB, FS: 1MB)" — otherwise files live in RAM.

3. Upload and talk

Upload, open the Serial Monitor at 115200 baud (line ending: Newline) or MicroCS Studio, and type C#:

> var led = new Pin("LED", GPIO.Output);   // LED_BUILTIN
> led.Toggle();
> Console.WriteLine(string.Join(",", I2C.Scan(0)));   // devices on Wire

C# bus 0 is Serial / Wire / SPI. More buses — in the sketch, before mcs_arduino_hal_init:

mcs_arduino_cfg_t cfg = MCS_ARDUINO_CFG_DEFAULT;
cfg.uart[1] = MCS_ARDUINO_UART(Serial1);    // UART.Open(1, ...)
cfg.i2c[1]  = &Wire1;                       // I2C bus 1

Set the pins of Wire / SPI the Arduino way before that (ESP32: Wire.begin(SDA, SCL), SPI.begin(SCK, MISO, MOSI); Arduino-Pico: Wire.setSDA() / setSCL()).

4. Options

The IDE cannot pass -D flags to libraries, so the package carries src/mcs_user_config.h. Edit it in Arduino/libraries/MicroCS/src/, or build the package with your settings:

python3 tools/make_arduino.py --profile embedded --no-ws2812
python3 tools/make_arduino.py --u8g2 --u8g2-displays ssd1306_i2c_128x64_noname   # U8g2 displays
python3 tools/make_arduino.py --config my_mcs_user_config.h

(--u8g2 also needs the U8g2 library from the Library Manager.)

PlatformIO

[env:esp32c3]
platform = espressif32
board = esp32-c3-devkitm-1
framework = arduino
lib_deps = https://github.com/amir1387aht/MicroCS
build_flags = -DMCS_ENABLE_WS2812=1
monitor_speed = 115200

Copy ports/arduino/examples/MicroCS_REPL/MicroCS_REPL.ino to src/main.cpp (add #include <Arduino.h> at the top), then pio run -t upload -t monitor. Options go into build_flags or include/mcs_user_config.h.

Your program on the board

python3 tools/mcs_remote.py --port /dev/ttyUSB0 put blink.cs /main.cs + run /main.cs

Troubleshooting

Symptom	Fix
region 'dram0_0_seg' overflowed / not enough RAM	a smaller profile: --profile embedded (or lowram)
files disappear after reset	the board has no filesystem partition (step 2), or LittleFS.begin(true) failed
characters echo twice / not at all	Serial Monitor line ending Newline; or use Studio
Wire.h: No such file on a core without Wire	add #define MCS_ARDUINO_NO_WIRE to src/mcs_user_config.h

More: ports/arduino/README.md (mapping, files, SD cards, embedding in your own sketch).