SD with SPI

[patc]

Dunno if anyone is interested but I wanted to read data from the SD card using SPI (too lazy to study sdhc!). However MISO and MOSI need to be swapped with each other and I ended up soldering a SD card holder on top of the Parallella's one (also added a decoupling 100nF Vdd/Vss).

I first tested on MicroZed and put my modified drivers on the Zedboard forum last weekend:
http://www.zedboard.org/content/sd-card ... standalone

then moved to the Parallella. However there's one modif:

#define SLAVE2_SELECT 3
static int select(void) {
SPI_Type *spi = SPI_REG(SPI1);

spi->CR &= ~SPI_CR_SSCTRL_MASK;
//spi->CR |= SLAVE0_SELECT << SPI_CR_SSCTRL_SHIFT; // MicroZed
spi->CR |= (SLAVE2_SELECT << SPI_CR_SSCTRL_SHIFT); // Parallella
spi->ER = SPI_ER_ENABLE_MASK;

if (wait_ready())
return RET_SUCCESS;

deselect();
return RET_FAILLED;
}

Those drivers are still pretty rough but seem to be working well.


(BTW it's a pity that U17 being not populated, those 12 MIO lines aren't available for something else)

[9600]

Why do you need to use SPI? Am I right in thinking you plan to run something other than Linux?

Cheers,

Andrew

[patc]

Hi Andrew, indeed I won't be using Linux and beside SD I plan to use SPI to control a TFT display as well.

While searching for already existing stuff regarding file access on SD card I noticed that I wasn't the only one looking for it, hence someone might find what I've put together useful.

[aolofsson]

Respect!

Andreas