STM32L471 WFI problem

[damh]

Posted on June 20, 2017 at 17:43

On STM32L471 (DEV_ID=0x6415, REV_ID=0x1007)

~4% of mcus do not enter standbymode and ignore the WFI instruction.

Does anyone have ideas how to get it working on all mcus? (tested with 150 pieces)

Is there any known bug/problem?

[Tesla DeLorean]

Posted on June 20, 2017 at 18:37

Are you looping on the WFI instruction? Anything driving NRST?

[damh]

Posted on June 20, 2017 at 19:05

yes, it's the cube function [HAL_PWR_EnterSTANDBYMode()]

NRST has an external pullup (10k) and capacitor (100nF) to GND.

In one case NRST is connected additionally to the debugger or in second case open, but there is no difference.

All other units (144 pcs.) work correctly with the same firmware.

[damh]

Posted on June 23, 2017 at 17:05

Is there a way to determine, why the wfi command is ignored? What flags have to be checked?