MMC card with spi-sd-card.c

Sebastian Huber sebastian.huber at
Tue Dec 23 08:15:34 UTC 2008

Sebastian Huber wrote:
> Gene Smith wrote:
>> I have been trying to use an MMC with the "spi/sd" drivers in RTEMS. I 
>> worked until it tries to send two commands in a loop waiting for idle 
>> conditon in an init routine:
>> rv = sd_card_send_command( e, SD_CARD_CMD_APP_CMD, 0);
>> CLEANUP_RVSC( rv, sc, sd_card_driver_init_cleanup, "Send: 
>> rv = sd_card_send_command( e, SD_CARD_ACMD_SD_SEND_OP_COND, 0);
>> CLEANUP_RVSC( rv, sc, sd_card_driver_init_cleanup, "Send: 
> These commands set the SD Card into SPI mode.

Oh, I guess I misunderstood you.  You want to use a MMC in SPI mode? There are
several ways to switch from MMC mode to SPI mode.  This one worked for all
cards I worked with.  We may use the alternatives if one approach fails.

Sebastian Huber, Embedded Brains GmbH

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