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I have now completed my I2C Master/Slave communication test. Quite happy with the results! Before getting started I needed to refresh my memory on I2C protocol, how Master and Slave devices would communicate, how data flow between devices. Found this nice tutorial on the web: http://www.best-microcontroller-projects.com/i2c-tutorial.html

Has I referred on previous posts, the PIC 16F690 will now support I2C protocol by hardware for the slave device, meaning that Interrupt Service Routine will be available, serving I2C Master whenever necessary without the necessity to pool the I2C bus. This also will permit Slave PIC to run other tasks like acquiring data from Analog-to-Digital inputs, control outputs, read inputs, etc, and still server PIC Slave without causing any delay on I2C bus. Unfortunately I2C Master is not supported by hardware for this PIC. Not a problem, Master PIC will receive commands from PC (Via RS232 interface - serial communication) that will be stored on buffer to be processed whenever possible!

For the test I’ve used 2 PICs 16F690 @ 4Mhz and 1 RS232 interface for debug. Master PIC will connect to Lab PC by RS232 (COM1) for debugging purpose and to Slave PIC by I2C bus.

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