Saturday, October 20, 2012

RGB Backpack - I2C on Propeller

Working with the Parallax Propeller Professional Development board and the Logos Electromechanical RGB Backpack.  Attempting to recreate the I2C connectivity I accomplished with the Arduino.  So far - NO LUCK.

At a high level I have attempted to modify a couple different I2C objects from the exchange, and use demos to communicate with the backpack - however the backpack pulls the SDA low and holds it there.

Without the backpack attached, my logic analyzer did report valid I2C data coming out of the Prop and decode it as I expected based on what I sent; this was uni-directional however - no ACK.

BTW - the Propeller also introduced the need for a level shifter, Frys had the MOS-FETs required so that looks good.

Next Steps - Focus on I2C understanding and perhaps other hardware to interface.  Checking out the 'kickstarts' examples next...


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    1. I did end up getting this to work. Required some messing around with the address a bit. The challenge seemed to be with the i2c bit that indicated inbound or outbound. I assumed it was the address in one of the situations however the extra bit threw me off.