"Gururaja Hebbar K R" gururajakr@sanyo.co.in wrote:

Hi,

I need few clarification regarding mmc csd structure declaration. I was taking Atmel mci as reference.

In ProductManualSDCardv2.2.pdf @ page 34 & ProdManualSDCardv1.9[1].pdf @ page 39, says

... ... ... C_SIZE_MULT 3 bit width ERASE_BLK_EN 1 bit width SECTOR_SIZE 7 bit width WP_GRP_SIZE 7 bit width WP_GRP_ENABLE 1 bit width

This seems to correspond with the SD Memory Card spec v1.01.

But in mmc.h file inside u-boot-1.3.4\include\asm-avr32\arch-at32ap700x.

Here, inside structure mmc_csd @ line

... ... ... c_size_mult:3 sector_size:5 erase_grp_size:5 wp_grp_size:5 wp_grp_enable:1

And this corresponds with the MMC spec.

So my doubt is, Shouldn't erase_grp_size come before sector size.

No. But sometimes, erase_grp_size just isn't there at all, and you have a 1-bit flag right before sector_size instead.

Currently, these values aren't actually used by u-boot, but I guess ideally, we should either read them correctly or not read them at all.

Haavard