STM32MP151 emmc OTP configure

[fantasylsdo]

Hello. We already have a custom board based on STM32MP151CAD3 with an eMMC. The following pins are different with default eMMC pins.

SDMMC2_CMD: PA0

SDMMC2_D1: PB7

As not default pins are used, we need to update OTP value. Here are my result.

OTP3 = 0x00000004

emmc_if_id=2: SDMMC2(uses non default AFmux defined in OTP).

OTP5 = 0x27A41094

SDMMC2_CMD = PA0 (bits[15:0]: port0=1=GPIOA, pin0=0, afmux0=9, mode0=4=AF;pull-up;medium-speed)

SDMMC2_D1 = PB7 (bits[31:16]: port1=2=GPIOB, pin1=7, afmux1=10, mode1=4=AF;pull-up;medium-speed)

However, it does not work. I also trace its ROM log. Attached is log.

[PatrickF]

Hi @fantasylsdo ,

as soon you set OTP3 to use non-default AFmux, you should define ALL the required pins by the BootROM.
Here you miss to define CLK and D0. Note: D1 is useless for eMMC at BootROM stage.

So, your OTP shoud look like:

• OTP3: 0x00000004
• OTP5: 0x10945391
• OTP6: 0x00002E94

(please double check values according to your needs)

Regards.

[fantasylsdo]

Hi Patrick. Thanks for your reply. 

I have a question about OTP5: 0x10945391. The mode of CLK is configured as 1 (no pull; medium speed). But I find in this link https://community.st.com/t5/stm32-mpu-products/changing-the-emmc-pins-with-otp/td-p/155797. The mode of CLK is configured as 4 (pull up; medium speed). Does it matter?

[PatrickF]

HI @fantasylsdo 

Internal pull-up on CLK is not so important as it is driven push-pull once initialized. Usually there is also an external pull-up.

Both configuration will work.

Regards.

[fantasylsdo]

Hi Patrick,

Thanks very much for fast and clear explanation. I appreciate it.

I tried it and found another issue. Regarding the ROM trace log, an error "MMC_NotEnoughBootDataRxErr" occurs. Attached is trace log and TSV file.

Do you know its cause?

[PatrickF · Accepted solution]

Hi @fantasylsdo ,

I think the issue is that you are using STM32MP15x Rev B. (from a very old stock I guess) which have issue booting from most eMMC due to too short data timeout.

Please refer to ES0438.

You must use STM32MP15 Rev. Z devices.

As a workaround, few eMMC was identified as working with Rev. B (Toshiba THGBMNG5D1LBAIL, THGBMDG5D1LBAIL, and Kingston EMMC04G-M627-X03U)

Please confirm your device version looking at package marking (or printed on console log during flash programming).

Regards.

[fantasylsdo]

Hi Pactrick, 

You are correct. I'm using  STM32MP151CAD Rev.B. Thanks for your kind advice. We will consider to change STM32MP15 Rev. Z devices.

Thanks for your efficient reply again.  I'll close this question.