Using emmc and fatfs with STM32F207

[o239955_st]

Posted on March 04, 2015 at 11:01

Dears,

I plan tu use an eMMC memory chip with an STMF32f207 connected to the SDIO interface (4-bits wide) and an FAT lib (from ST). The eMMC choice is dictated by wear levelling and ECC management facilities.

All the system will run under FreeRTOS.

I never do it before and before begining the hardware, I should answer to some questions:

1) Is it complexe to develop the low-level driver between the FAT lib and the eMMC.

2) In the past I have been developed a driver for NOR serial Flash and before programming byte in a non-erased sector, the driver should read all sector before changing data (classical scheme). Is it the same with eMMC and should the STM32 get enough RAM to read entire sector (some NOR flash have 256kb sector)

Thanks for your help

Olivier

[Tesla DeLorean]

Posted on March 04, 2015 at 14:54

Doesn't the eMMC just behave like a soldered down MicroSD card?

http://www.sireda.com/fo/eMMC-Socket-1.htm

The blocking of the NAND is handled internally with SD cards, although you want to using formatting that is aligned naturally with the erase block size, so clusters, fat don't span a boundary causing a significant degradation of throughput.