Transflash SD vs MMC by SPI

[laserted]

I've been implementing 3.3 and 5v MMC and SD cards on PICs for some time now with success, but recently received a large batch of TransFlash SD cards that won't work for me - won't even get past init. They're micro-SD cards of SanDisk descent, in original SanDisk micro-to-standard SD adapters. I have sizes from 16mb to 128mb, and am trying with both Fat and Fat32 libraries. The cards operate fine in my Linux and Win32 machines, as well as other embedded devices (cameras, PDAs, MP3 etc).

I fully realize that SPI (as implemented in these libraries, at least) is a compatibility mode of MMC, not necessarily SD or anything else for that matter - does anyone have recent experience working with Transflash/MicroSD successfully?

I'm not too concerned if I can't use these cards; 1GB cards in full-size SD are so cheap these days to be a non-issue; just when you only need to play back 2mb worth of data, sending out 1GB cards seems silly....

Thanks,

Ted.

[ckielstra]

The SPI-bus is an optional communication mode in the microSD standard (compulsory for normal SD). I don't know how you can check if SPI is supported or not.

1-bit bus mode is compulsory but that is a major rewrite of your code.

[asmallri]