| name | hardware |
| description | Read and control I2C and SPI peripherals on Sipeed boards (LicheeRV Nano, MaixCAM, NanoKVM). |
| homepage | https://wiki.sipeed.com/hardware/en/lichee/RV_Nano/1_intro.html |
| metadata | {"nanobot":{"emoji":"🔧","requires":{"tools":["i2c","spi"]}}} |
Hardware (I2C / SPI)
Use the i2c and spi tools to interact with sensors, displays, and other peripherals connected to the board.
Quick Start
# 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)
Before You Start — Pinmux Setup
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:
- Stop WiFi if using shared pins:
/etc/init.d/S30wifi stop
- Load i2c-dev module:
modprobe i2c-dev
- Configure pinmux with
devmem (board-specific)
- Verify with
i2c detect and i2c scan
Safety
- Write operations require
confirm: true — always confirm with the user first
- I2C addresses are validated to 7-bit range (0x03-0x77)
- SPI modes are validated (0-3 only)
- Maximum per-transaction: 256 bytes (I2C), 4096 bytes (SPI)
Common Devices
See 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.
Troubleshooting
| 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) |
