I2C Slave example

About

This example allows you to hook up LEDs and Switches to an Arduino and control
it over an i2c bus.  It uses an address register just like normal i2c devices
do and also because most i2c code expects an i2c device to use registers for
reading and writing.  e.g.  linux i2cget/i2cset/i2cdump and the linux i2c
library.


Details

The i2c slave has 4 registers, 3 for reading, one for writing.

Registers

0x00, REG_READ_STATUS
0x01, REG_READ_LEDS
0x02, REG_READ_BUTTONS
0x03, REG_WRITE_LEDS


Usage

From linux.  See i2cget/i2cset/i2cdump man pages for more details.

Read status:

sudo i2cget -y 1 0x21 0x00 c

Read leds:

sudo i2cget -y 1 0x21 0x01 c

Read switches:

sudo i2cget -y 1 0x21 0x02 c

Set leds on:

sudo i2cset -y 1 0x21 0x03 0x07 b

Set leds off:

sudo i2cset -y 1 0x21 0x03 0x00 b


Copyright

The code is copyright Dominic Clifton.

License

GPL v3