New STM32L431KC does not program or run unless mass erase is performed first.

[gerhard]

When first programming a New STM32L431KC, it does not program or run unless mass erase is performed first.

I use IAR and STLINK/V2

From IAR, I try:

a) Download program - uC does not run, even after reset

b) Start debugging session - Does not execute code. Gets stuck "hang" on HAL_Delay(xx) statement.

When I use STM32MXProgrammer and ERASE all flash, then the programming works, and I can download from IAR.

Any help appreciated.

[waclawek.jan]

I don't use IAR but you can try to power-cycle the board after first programming.

Alternatively, change explicitly the 0x0000'0000 remap to user FLASH at the beginning of your program; or, maybe better, set VTOR to 0x0800'0000.

JW

[gerhard]

Thanks, and yes that works.

The F051, L051, L052 and others does not do that.

The only difference on the boards is the on the L431 I use a 32KHz resonator.

Perhaps that is it.