talking to the uMMC

I hooked up the uMMC to the PC tonight. I couldn't find an MMC or SD card around, so I just had to verify the connection and query the status of the system.

The first command I used was Z which queries the system status - the return was error code E08: Card not inserted; the other command I typed was V to request the system version and serial number - the return is kinda funny: VVV.MM SN:UMM1-NNNN-NNNN is expected, but I got 101.56 SN:UMM1-OEM - I have no serial number...

Ah well - nice to have something work. In the breadboard, I have the Vcc and Gnd on the uMMC going directly to the 5V from my power supply; the G, T, and R on the uMMC connect to the TTL Gnd, TTL Tin, and TTL Rout on the MAX232 (Sipex in this case); finally, the PC Serial has Gnd (5), Tx (3), and Rx (2) connected to the Gnd, RS-232 Rin, and RS-232 Tout. The PC serial uses 8N1 w/ no flow control @ 9600 as the default.