si2c

Software based I²C library ( I²C-Slave ) for AVR's atmega

Whats inside

• software i2c-slave for avr's atmega family
• software i2c-master for raspberry pi ( or all devices which support wiringPi )

Features not finished yet

• time-streching
• software i2c-master for avr's atmega
• software watchdog ( please use the watchdog of your atmega )

That works

• read and write from raspberry to atmega8 over pins you can choose ;)
• use speeds at your own choise

How to start

Dependencies

• make
• avr-gcc
• gcc
• wiringPi-library ( on raspberry )

On AVR's site

Setup

Please change the variables inside config.h in the avr/ folder

build

• change to source-directory
• run make -f make/MakefileAVR.mk firmware

Raspberry

build

• change to source-directory
• run make -f make/MakefileGPIO.mk si2c

Command line interface

Usage:
-c <SDA-Port> <SCL-Port> <TIME>
-i: init - set SDA/SCL to high
-as <address>: send address on write mode
-ar <address>: send address on read mode
-s: Send i2c-Start
-r <byte>: Read i2c-byte
-w <byte>: Send i2c-byte
-e: Send i2c-stop
-t <chipAddress>: Test if address is present

For example, if you would like to send an byte

si2c -c 17 27 1 -i -s -as 4 -w 1 -w 1

• this will send byte 1 to register 1
• the target chip Address is 4
• SDA-Pin is GPIO 17
• SCL-Pin is GPIO 27