How to use the LPBAM feature: An example using STM32U5 board

[Sarra.S]

This article provides guidelines on how to use the LPBAM feature in the STM32U5 series to allow peripherals to be autonomous and optimize the power consumption in STOP2 mode.

The LPBAM stands for low-power background autonomous mode. It is an operating mode available in the STM32U5 products series that allows peripherals to be functional and autonomous in Stop 2 mode independently from the device power modes without any software running.

Two major advantages result from using the LPBAM feature : 

•  Power consumption is optimized (around 4µA in STOP2) 
• CPU bandwidth is offloaded (peripheral configuration and transfers are done by DMA) 

The following Wiki article provides LPBAM use cases and a complete example of how to drive LPGPIO with code, scenario configuration, and power consumption measurement. 

[Gautham19]

LPGPIO example provided is not working @Sarra.S 

[Sarra.S]

Hello @Gautham19, 

Could you elaborate on what doesn't work exactly? 

I would be happy to help! 

[Gautham19]

@Sarra.S  I have tried it with Nucleo board u575, when tried to debug. When the code reaches the 

MX_LPDMA1_Init(); the debugger connection is lost and no response I tried to track the pin PA1 pin with logic analyzer but pin state is not toggled.

[Sarra.S]

Hello @Gautham19 

Make sure debug pins PA14 and PA13 are not set to analog. 

Then reset your board and try stepping through the code 

[Gautham19]

Hello @Sarra.S ,

Thanks for the debug pin configuration . I made changes with the Debug pin, it is set as analog earlier now I changed to Debug pin.

But the pin toggle is not working, it remains the same.

[Gautham19]

Hello @Sarra.S ,

I have configured LPGPIO_PIN_5 as output it is updated in LPGPIO1->MODER, but during run time the LPGPIO1->ODR, LPGPIO1->BSRR, LPGPIO1->BRR is not  getting updated.