Just curious, do all writes by the CPU increment the cart address counter? I wrote blog post on bit banging the i2c protocol over the cart pins so that the Lynx can talk to i2c I/O expanders and serial EEPROMS in the CGD dev cart design. After looking at all the documentation and Karri's design, it looks to me like I would need to do two dummy reads on the cart data register to increment the address counter enough to toggle the state of the A1 line for clocking the i2c protocol. If the writes to the AUDIOIN pin increment the address counter, then there only needs to be one dummy read because the AUDIOIN write and the dummy read are enough to toggle A1.
Does anybody know if writing to the AUDIOIN bit in Mikey's general I/O register increments the cart address counter?
BTW, I'm getting very close to a final design for the CGD dev cart. When it is finished, I'll be releasing the hardware schematics and gerbers under a BSD license so it will be free for anybody to have boards made and/or to extend the design.
--Wookie
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Do writes to Mikey registers increment address counter?
Started by Wookie, Jan 17 2010 11:11 AM
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