Hello,
I’ve had a lot of experience with uALFAT and I just moved up to the ALFAT. I’m having problems getting an SD card to mount. Whenever I try a mount command I get 0x11 in return, indicating that the media initialization failed. I’ve verified the wiring connections, tried several different cards (both SD and uSD) and am having no success. There is a 22uF cap across the supply lines to the card, so that’s not the issue. I’ve looked at all the lines on a scope.
Whenever I try to mount it I see a short period of time where D2 and D3 are low (~100ns), then they decay back up to 3.3V (due to the 47k pullups). D0 and D1 do something similar, but instead of staying low they seem to toggle about ten times at 100MHz. The clock line seems to decay up for about 3.8us then either goes low immediately or stays high for an additional 5us. The CMD line is always high. The only thing that changes when I insert/remove the card is a slight change in the decay times.
I noticed on the ALFAT eval board there are connections to the ALFAT for card detect (CD) and write protect (WP). However, the ALFAT datasheet says to not use the pins that are connected to CD and WP in the eval board schematic. Can I assume that this feature was planned but never implemented?
I tried to send the ALFAT the J command to get status. It returns 0x10, indicating that the SD detect pin state is 0. Is this just part of the unimplemented function? There is no mention anywhere in the datasheet about a detect pin.
Any suggestions would be appreciated.
Thanks,
Mike