Hi, Our boot source is eMMC via SDMMC2 bus (boot pins [2:0]='010'). Before booting, in the first access to the chip , is the MPU chip could be configured through USB OTG bus? Thanks in advnce, Shlomi

SPele.1 · ‎2021-06-29

PatrickF · ‎2021-06-29

Hi,

I'm not sure to catch your request. What do you mean by 'configure the MPU chip' ?

Do you talk about Flashing the eMMC ? Fusing some OTP ?

With BOOT=0b010 (eMMC), If eMMC FSBL header is not valid (i.e. no magic number, bad CRC), the BootROM will fallback to USB boot. This is useful, e.g. in production when booting from virgin eMMC, to allow flashing with CubeProgrammer without having to play with BOOT pins.

You could find information in https://wiki.st.com/stm32mpu/wiki/STM32MP15_ROM_code_overview

Regards.

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PatrickF · ‎2021-06-29

Hi,

I'm not sure to catch your request. What do you mean by 'configure the MPU chip' ?

Do you talk about Flashing the eMMC ? Fusing some OTP ?

With BOOT=0b010 (eMMC), If eMMC FSBL header is not valid (i.e. no magic number, bad CRC), the BootROM will fallback to USB boot. This is useful, e.g. in production when booting from virgin eMMC, to allow flashing with CubeProgrammer without having to play with BOOT pins.

You could find information in https://wiki.st.com/stm32mpu/wiki/STM32MP15_ROM_code_overview

Regards.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

SPele.1 · ‎2021-06-29

Patrick,

No - I'm talking about booting in production.

When we want to boot via USB OTG in production, when our eMMC is empty - in this case MPU does not see anything in eMMC and boot through the USB OTG?

Many thanks for your fast reply,

Shlomi