LEDs and buttons on STM32 MPU boards

Applicable for

STM32MP13x lines, STM32MP15x lines, STM32MP23x lines, STM32MP25x lines

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1. Introduction

The following paragraphs describe the functional mapping of the LEDs and buttons.

2. Description

2.1. LEDs

LED color	Purpose
Green	Can be used at runtime for Linux examples
Red	Used to show Cortex-A boot information
Blue	U-Boot entering / exit indication then Linux heartbeat, which blinks as long as Linux is alive on the Cortex-A
Orange	Used for STM32Cube examples verdict, on STM32MP15 and STM32MP25. Free for user on STM32MP13.

2.2. Buttons

Button label	Purpose
WAKE UP	Allows the platform to be woken from any low-power mode
USER1	Used at boot time by U-Boot to enter USB programming mode with STM32CubeProgrammer. This avoids manipulation of the STM32 MPU ROM code overview#Boot device selection when a valid U-Boot image is already present in the board. Can be used at runtime for Linux examples or STM32Cube examples, on STM32MP15. Used at runtime for Linux on STM32MP25.
USER2	Used at boot time by U-Boot to enter Android Fastboot mode. Not yet supported on STM32MP25 Used at runtime for Linux, on STM32MP13. Can be used at runtime for STM32Cube examples on STM32MP25.
TAMPER	Allows to generate an external tamper event. Only present on STM32MP13 board and STM32MP25 board.

3. On STM32MP13x lines 

You can refer to the STM32MP135x-DK - hardware description to determine to which GPIO each function is mapped.

4. On STM32MP15x lines 

You can refer to the respective board hardware descriptions to determine to which GPIO each function is mapped:

• STM32MP157x-EV1 - hardware description for the Evaluation boards
• STM32MP157x-DKx - hardware description for the Discovery kits.

5. On STM32MP25x lines 

You can refer to the respective board hardware descriptions to determine to which GPIO each function is mapped:

• STM32MP257x-EV1 - hardware description for the Evaluation boards,
• STM32MP257x-DKx - hardware description for the Discovery kits.