m5stamp-c3dev

This is a development board for the M5Stamp C3 (RISC-V/FreeRTOS).

Hardware

• External USB-C port for JTAG debugging
• Support for LCD panel and SD card
• Selecting a power supply
• Switch(GPIO9) to enter loader mode
• Pin headers to expose usable GPIOs to the outside
• The size is just Japanese business card

Sample Sources Included

• TrueType font with Japanese output to LCD - test_freetype.cpp
• Output PNG images in SD card to LCD - test_tinypng.cpp
• NTP synchronization via WiFi connection - test_nvs_wifi.cpp
• Test ADC on GPIO0
  • UNIT Light - main.cpp
• Test I2C on GPIO18, 19
  • UNIT ENV III - test_i2c_gpio1819.cpp
  • UNIT ULTRASONIC - test_i2c_gpio1819.cpp
• Test UART on GPIO18, 19
  • UNIT GPS - test_uart_gpio1819.cpp
• WebAssembly execution with Wasm3
  • Analog clock using AssemblyScript - test_wasm3_clockenv.cpp
  • GPS GSV viewer using AssemblyScript - test_wasm3_gpsgsv.cpp
  • 3D Cube Demo using AssemblyScript - test_wasm3_imu6886.cpp
• Usage of SPIFFS, which stores TrueType fonts and .wasm binaries (parttool.py and spiffsgen.py tools)
• Use of NVS (cryptographically enabled key value store) that stores WiFi passwords (nvs_partition_gen.py tool)
• Building libraries and managing dependencies using the esp-idf build system
• Visual Studio Code C/C++ Extension configuration and JTAG debugging configuration in conjunction with openocd
• AssembyScript sharing method between web browser and microcontroller - wasm

This repository contains MIT Licensed PCB data and example programs.

Demo

Video

• 📼 Demo(LCD)
• 📼 Demo(Wasm3)
• 📼 Demo(3D Cube)

Web Simulation

• 🕸 AssemblyScript Analog Clock
• 🕸 AssemblyScript GPS GSV Viewer

Schematic

#Unit	Name	Note	Where to get it
U1	AE-USB2.0-TYPE-C	USB 2.0 Type-C Break out board	akizukidenshi.com (JP)
U2	M5STAMP-C3	M5Stamp C3	+ M5Stack + SWITCH SCIENCE (JP)
U3	KMR-1.8SPI	KMR-1.8 SPI marked LCD and SD card interface	+ amazon.co.jp (1) + ja.aliexpress.com
R1 - R2	5.2K Resistor	Pull-down for USB Power supply	-
R3 - R7	10K Resistor	SPI pull-up	-
JP1	Jumper pin	Select external power supply	akizukidenshi.com (JP)
SW1	Tact switch	for loader mode and utility	akizukidenshi.com (JP)
J1	12 Pin header	You can use the one that comes with the M5Stamp C3 Mate	-

PCB and Gerber data

• KiCad 6 PCB
• Gerber Data
• FG06-C3DEV REV.B (2枚) - M5Stamp C3 向けの開発用基板 - 部品なし基板のみ - 130円

Example Source

Require

• Setup ESF-IDF release/v5.1

get_idf or (Windows) ESP-IDF command prompt

# Linux or macOS ->
$ alias get_idf='. $HOME/esp/esp-idf/export.sh'
$ get_idf
# <-

Detecting the Python interpreter
... snip ...
Done! You can now compile ESP-IDF projects.
Go to the project directory and run:

  idf.py build

$ echo ${IDF_PATH}
/home/hiromasa/devel/toolchain/esp/esp-idf

$ riscv32-esp-elf-gcc -v
Using built-in specs.
COLLECT_GCC=riscv32-esp-elf-gcc
... snip ...
gcc version 12.2.0 (crosstool-NG esp-12.2.0_20230208)

openocd (Optional)

$ openocd -v
Open On-Chip Debugger v0.12.0-esp32-20240318 (2024-03-18-18:25)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html

Build and Execute

1. git clone and build (Please add --recursive)

git clone --recursive https://github.com/h1romas4/m5stamp-c3dev
cd m5stamp-c3dev
idf.py build

Note: If you get a compile error, change the sdkconfig back to the Git one. In some cases, the target of sdkconfig is changed to esp32 instead of eps32c3.

2. Write Partition table

idf.py partition-table-flash

3. Write TypeType font to SPIFFS

parttool.py write_partition --partition-name=font --partition-subtype=spiffs --input resources/spiffs_font.bin

4. Write WebAssembly(.wasm) to SPIFFS

parttool.py write_partition --partition-name=wasm --partition-subtype=spiffs --input resources/spiffs_wasm.bin

5. Write main program to go!

idf.py flash monitor

Setup WiFi (Optional)

1. Change WiFi Setting

nvs_partition.csv: Set own [ssid], [password]

key,type,encoding,value
wifi,namespace,,
ssid,data,string,[ssid]
passwd,data,string,[password]

2. Create NVS Partition file

python ${IDF_PATH}/components/nvs_flash/nvs_partition_generator/nvs_partition_gen.py generate nvs_partition.csv nvs_partition.bin 0x6000

3. Write NVS Partition

esptool.py write_flash 0x9000 nvs_partition.bin

4. Run

NTP synchronization is performed by pressing the SW1 after the startup logo.

idf.py monitor

Select connected GPIO18 and GPIO19 device (Optional)

idf.py menuconfig

C3DEV Configuration → Select GPIO 18/19

3D Cube Demo

JTAG debug with Visual Studio Code

Require setup ESP32_TOOLCHAIN_HOME

$ echo ${ESP32_TOOLCHAIN_HOME}
/home/hiromasa/.espressif/tools/riscv32-esp-elf

1. Connect the PC to the USB Type-C of the U1
2. Open the source file in Visual Studio Code.
3. Run Task "openocd (debug)" @see .vscode/tasks.json
4. Set a breakpoint in the source code.
5. Debug Launch (GDB) @see .vscode/launch.json The first time you start the program, it will often fail, so if you get an error, retry.

Note

If the LCD color is inverted.

main/main.cpp

    // If the color is inverted, set to 1.
    tft.invertDisplay(0);
    // tft.invertDisplay(1);

Create SPIFFS partition file from file system

python ${IDF_PATH}/components/spiffs/spiffsgen.py 0x100000 resources/font resources/spiffs_font.bin
python ${IDF_PATH}/components/spiffs/spiffsgen.py 0x10000 resources/wasm resources/spiffs_wasm.bin

Change the output destination of the log to U1 Serial/JTAG.(Don't forget to put it back)

Component config → ESP System Settings → Channel for console output

idf.py menuconfig

AssemblyScript and Wasm3

Build AssemblyScript

cd wasm/clockenv # or wasm/gpsgsv or wasm/imu6886
npm install

Web Browser Development

npm run asbuild:web
npm run start
# http://localhost:1234/

SPIFFS Build and Flash

npm run asbuild
cd ../../
python ${IDF_PATH}/components/spiffs/spiffsgen.py 0x10000 resources/wasm resources/spiffs_wasm.bin
parttool.py write_partition --partition-name=wasm --partition-subtype=spiffs --input resources/spiffs_wasm.bin

Dependencies

Thanks for all the open source.

Name	Version	License
esp-idf	release/v5.1	BSD License
arduino-esp32	3.0.2	LGPL-2.1 License
M5EPD	0.1.5	MIT License
UNIT_ENV	0.0.7	MIT License
M5Unit-Sonic	0.0.2	MIT License
Adafruit_GFX	1.11.9	BSD License
Adafruit_BusIO	1.16.1	MIT License
Adafruit-ST7735-Library	1.10.4	MIT License
tinyPNG	0.11	MIT License
lwgps	v2.1.0	MIT License
Wasm3	master(045040a9)	MIT License
AssemblyScript	0.27.29	Apache-2.0 License
源真ゴシック	-	SIL Open Font License 1.1

License

MIT License (includes PCB data and example source)