I'm trying to get RRnet connected to the MMC64 working. I can access the RRnet but I get intermittent results. I'm writing #$0a, #$1c to $df13 to initialize the MMC64, then I toggle bit 1 in $df11 to read #$64 and Revision# out of $df13, leaving bit 1 in $df11 enabled. Finally I'm clearing bit 3 in $df11 to put clockport IO at $de00.

I don't know if this is the correct register settings for transparent clockport access, but the documentation is sparse. What exactly does bit 1 in $df11 ("card selected") imply by the way?

Can't help with RR-net, but "card select" controls /CS line for MMC/SD card. It needs to be 0 for the card to respond to commands. It's also used to synchronize SPI bytes - toggling it before commands helps with some cards.

Hmm.. so it shouldn't interfere with the clockport access then. How exactly does bit 0 and 5 in $df11 correlate?

I don't remember if bit5=1 also disables cartridge I/O lines, but that would be logical (assuming Oliver had enough I/O pins available).

Ok. Just borrowed a MMC64 so I'll check it out ...

I emailed Jens Schoenfeld and got a pretty interesting answer back.



It's all relevant information, however since I'm on a C64 this is probably not related to my problem. I've emailed back and currently waiting for response. I'll keep you posted.