- Last edited 8 months 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|
|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. Free for user on STM32MP13.|
|WAKE UP||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.
|TAMPER||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.