SmartTile I2C Addressing

[john23]

We ordered a custom smarttile PLC board with extra digital inputs and outputs (I2C). I tried using I2C_read and I2C read function to write or read the outputs and inputs but it did not work. How do I map the I2C to input/output addresses, so I can read and write to them?  The input address on the documentation provided is  0X21 The output address are  0X20, 0X22, 0X23 and 0X24. I would really appreciate any help to address this. Thank You.

[support]

You can study the example on how to use the I2C commands from the I2C-FRTC manual:

www.triplc.com/documents/I2C-FRTC-UserGuide.pdf

The example accesses the M24M01 I2C EEPROM available on the I2C-FRTC itself which is not available on the SmartTILE but you can study the example by also refering to the datasheet of the M24M01.

I have attached another example program which is to read the RTC chip DS1338 available on the SmartTILE-Fx itself so you can experiment with it directly.

By studying these two examples you should be able to adapt them to access your own I2C device.

Note: The I2C signals go directly to the CPU so be very careful when you are interfacing with external I2C device as any wrong connection or bad voltage can damage the CPU pin directly.

On the I2C-FRTC used with the FMD PLCs there are additional I2C buffering IC to protect against damage to the CPU due to installation error. This is not available on the SmartTILE-Fx since the signal pins go directly to the CPU.