- Last edited one year ago ago
LEDs and buttons on STM32 MPU boards
The following paragraphs describe the functional mapping of the LEDs and buttons.
|Can be used at runtime for Linux examples
|Used to show Cortex-A boot information
|U-Boot entering / exit indication then Linux heartbeat, which blinks as long as Linux is alive on the Cortex-A
|Used for STM32Cube examples verdict, on STM32MP15. Free for user on STM32MP13.
|Allows the platform to be woken from any low-power mode
|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 boot time by U-Boot to enter Android Fastboot mode.
Used at runtime for Linux, on STM32MP13.
|Allows to generate an external tamper event. Only present on STM32MP13 board.
3 On STM32MP13x lines 
On STM32MP135F-DK Discovery kit, the GPIO assignment is as follow:
- The green LED is on the IO expander pin GPB6
- The red LED and USER2 button are on the pin PA13
- The blue LED and USER1 button are on the pin PA14
- The orange LED is on the IO expander pin GPB7
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.