application specific SEND_OP_COND (CMD55 + ACMD41), go ahead and allow
100 tries. This gives a timeout of a second rather than the ~100ms
the old style produces.
I've had one old 16MB SD card which needs the extra time. I've now
had reports from the field that other cards need this too.
Originally done at BSDcan 2007 while waiting to give my embedding
madness minitalk.
SD Simplified specification, as well as other SD and SDIO
implemenations I've examined, suggest this disclaimer may be required.
It is unclear to me exactly what the license would be for, or why it
might be required. Err on the side of caution and include this
disclaimer so anybody deploying this code can judge for themselves. I
have no further unformation about the details.
should be easily adapted to SD 2.0 (aka SDHC), SDIO, MMC and MMCplus
cards. At the present time, there's only one bridge driver for the
ARM9 based Atmel AT91RM9200.