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allard
allard
Senior
February 1, 2021
Question

Toggling PA10

  • February 1, 2021
  • 5 replies
  • 1390 views

I'm trying to use PA10 to drive a simple LED (custom board), but the I/O doesn't switch at all.

PA10 is not used in any of the device trees. 

gpioinfo gpiochip0

reports the I/O as "unused" and "output", but switching the I/O with 

gpioset gpiochip0 10=1

doesn't work. The voltage on the pin stays at 1.7V.

PA10 can also function as OTG_FS_ID or OTG_HS_ID, so maybe this causes problems? I do not use USB in my kernel device tree.

This topic has been closed for replies.

5 replies

PatrickF
PatrickF
ST Employee
February 1, 2021

Please check uBoot DT regarding PA10, which might still be activated as OTG_ID pin.

See https://wiki.st.com/stm32mpu/wiki/How_to_configure_U-Boot_for_your_board#USB_OTG_node

Regards.

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allard
allardAuthor
Senior
February 1, 2021

My u-boot devicetree contains:

&usbotg_hs{
	u-boot,dm-pre-reloc;
 
	/* USER CODE BEGIN usbotg_hs */
	u-boot,force-b-session-valid;
	hnp-srp-disable;
	dr_mode = "peripheral";
	/* USER CODE END usbotg_hs */
};

So, the ID pin should be unused in uBoot?

PatrickF
PatrickF
ST Employee
February 1, 2021

Are you using the latest Openstlinux-5.4-dunfell-mp1-20-11-12 ?

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allard
allardAuthor
Senior
February 1, 2021

I'm at 20-06-24 with DISTRO_VERSION 3.1-snapshot-20210201

OlivierK
OlivierK
ST Technical Moderator
February 8, 2021

​Hi allard (Community Member),

VDD3V3_USBFS is used to supply OTG_VBUS and OTG_ID (PA10) pins. So,

VDD3V3_USBFS must be supplied as well when USB high-speed dual-role-port or USB

high-speed device is used. If not used, should be connected to VDD.

This is an extract of the App note

https://www.st.com/resource/en/application_note/dm00389996-getting-started-with-stm32mp151-stm32mp153-and-stm32mp157-line-hardware-development-stmicroelectronics.pdf

Regards,

Olivier

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