STM32L412 DFU mode after reset

[b.a.]

Hi,

I was wondering on how to access USB DFU mode on STM23L412.

As it seems, I'll have to power up the board to be able to reach it.

Just resetting does not seem to be enough...

Is this so, or am I doing something wrong?

I tie Boot0 to VDD and pull nRESET to GND by the means of a tactile switch. There are 100nF to GND and 330Ohm in series.

Cheers,

Bob

[Uwe Bonnes]

The description of SYSCFG_MEMRMP says that the values from boot are transferred on reset. Resisters that are only reset on power up, like DBGMCU_CR , are explicitly noted "System reset: not affected". So it seems you do something wrong. Do perhaps the option bits disable the boot pins?

[b.a.]

I observe the same behavior with a NUCLEO32 L412 board

COULD be a hint that it's not a hardware/layout/schematic problem of my custom board?

I will check the option bits - thanks for the advice!