Read and control I2C and SPI peripherals on Sipeed boards (LicheeRV Nano, MaixCAM, NanoKVM).
Use the i2c and spi tools to interact with sensors, displays, and other peripherals connected to the board.
# 1. Find available buses
i2c detect
# 2. Scan for connected devices
i2c scan (bus: "1")
# 3. Read from a sensor (e.g. AHT20 temperature/humidity)
i2c read (bus: "1", address: 0x38, register: 0xAC, length: 6)
# 4. SPI devices
spi list
spi read (device: "2.0", length: 4)
Most I2C/SPI pins are shared with WiFi on Sipeed boards. You must configure pinmux before use.
See references/board-pinout.md for board-specific commands.
Common steps:
/etc/init.d/S30wifi stopmodprobe i2c-devdevmem (board-specific)i2c detect and i2c scanconfirm: true — always confirm with the user firstSee references/common-devices.md for register maps and usage of popular sensors:
AHT20, BME280, SSD1306 OLED, MPU6050 IMU, DS3231 RTC, INA219 power monitor, PCA9685 PWM, and more.
| Problem | Solution |
|---|---|
| No I2C buses found | modprobe i2c-dev and check device tree |
| Permission denied | Run as root or add user to i2c group |
| No devices on scan | Check wiring, pull-up resistors (4.7k typical), and pinmux |
| Bus number changed | I2C adapter numbers can shift between boots; use i2c detect to find current assignment |
| WiFi stopped working | I2C-1/SPI-2 share pins with WiFi SDIO; can't use both simultaneously |
devmem not found | Download separately or use busybox devmem |
| SPI transfer returns all zeros | Check MISO wiring and device power |
| SPI transfer returns all 0xFF | Device not responding; check CS pin and clock polarity (mode) |