I2C/Wire Test

A small guide to show the communication via I2C between the ATtiny85 (RPi-WS2812-HAT) and Raspberry Pi.

• Activate I2C:

  $ sudo modprobe i2c_bcm2708 baudrate=400000
  $ sudo modprobe i2c-dev
  

• Install i2c-tools:

  $ sudo apt-get install i2c-tools
  

• Test I2C bus:

  $ sudo i2cdetect -y 1
  

• Set first LED to red (r=0x7F g=0x00 b=0x00) and second to blue (r=0x00 g=0x00 b=0x7F):

  $ sudo i2cset -y 1 0x20 0x00; sudo i2cset -y 1 0x20 0x7F; sudo i2cset -y 1 0x20 0x00; sudo i2cset -y 1 0x20 0x00;
  
  $ sudo i2cset -y 1 0x20 0x01; sudo i2cset -y 1 0x20 0x00; sudo i2cset -y 1 0x20 0x00; sudo i2cset -y 1 0x20 0x7F;