The question about STM32MP157CAC3 supply

[DFomi.1]

Hello.

I have used the STM32MP157A-DK1 this year and I have learned to work with it. Now I develop my own PCB with STM32MP157CAC3. There is a 12-V external power supplier in it. I do't use USB Type-C. Can I do like this? I care about pins USB_PWR_CC1 and USB_PWR_CC2. It seems to me that they will not allow starting the processor without USB.

Thanks!

[PatrickF]

Hi,

no issue if you build your own board, for sure CC lines check can be skipped in Device Tree.

See https://community.st.com/s/question/0D53W00000qvZllSAE

Regards,

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[DFomi.1]

Hi, Thank you for your answer. I haven't found this string in the project tree:

/* st,adc_usb_pd = <&adc1 18>, <&adc1 19>; */

This string for dk2 plate. I work with dk1. Although, it is nether mind...

Could you prompt, in which file I can find this string? Can I to fix my error, if I work with Linux Kernel, not uboot?

P.S. I found this string in the uboot tree, but I still don't understand what i have to do, if I work with Linux Kernel...

Thanks!

[PatrickF]

Hi,

sound normal that your don't find it in your custom project.

Location and presence of this definition depend on how the project DT has been sourced:

• In Upstreamed Started Package DT, it is located in stm32mp157a-dk1-u-boot.dtsi file. See https://wiki.st.com/stm32mpu/wiki/STM32MP15_device_tree#U-Boot
• In CubeMx generated DT for board STM32MP157A-DK1, you should find it in stm32mp157a-YOURCUBEMXPROJECT-mx-u-boot.dtsi file. See https://wiki.st.com/stm32mpu/wiki/STM32MP15_device_tree#U-Boot_2
• In CubeMx generated DT for a custom board project, this definition will not be present (as it is linked to DK1 or DK2 board hardware)
  • So, by default, there is neither no u-Boot warnings nor worries related to USB-C CC lines.
    • It should be added manually if needed (which is not your case as you don't plan to have USB-C as in DK1/DK2)

Regards.

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[DFomi.1]

Thank you very much, It helped me!

Could you prompt me some file where is sequence of actions of the processor when turning on the power and connecting the micro SD?

My processor does not wake up(( There is no signal on the I2C4_SDA and SCL... Voltage

does not appear VDD_DDR and DDR_REF. I mean my own plate, not dk1. I use only DDR and ethernet periphery on my plate.

P.S. I can see the string in console " Exception mode=0x00000016 at: 0x2fff2d17 "

Do you know what does it mean?