Hacked SPI Decoder

July 25, 2007

SPI Decoder Hackery

Here’s a design I just threw together for a hokey SPI decoder so I can watch what is going on internally in the Honda Music Link. It’ll read both SPI lines and turn it into RS232 data on the PC. Basically, the software on the PICs will just data out of the SPI buffer as it fills (and triggers an interrupt) then write that out the UART. Should work, I think. The only big problem will be the decoding software on the PC.

Anyone want to write up some decoding software for me? It should be easy to do… Just needs to watch a serial port (or maybe both) and decode packets as they come in. Hell, if you can write the framework for it, I can add the decodes as I figure them out.

(The point of this is to basically reverse engineer how Honda talks to CD changers.)