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Unable to enter Standby mode on STM32F030

Question asked by engblom.hakan on Aug 6, 2014
Latest reply on Aug 13, 2014 by engblom.hakan

I have a board equipped with a STM32F030R8T6. It runs for app. 0.1 s and then goes into StandBy (or should) for 10 seconds. It is woken up by IWDG. It looks like it is working OK,  it executes and goes to _some_ kind of low power mode for 10 seconds, and looking at the reset reason in RCC_CSR it is reset by IWDG.

However when looking at the PWR_CSR the SBF bit, it is never set.
Further, when experimenting with the different Option Byte settings for whether a reset should be done instead of entering standby or stop (nRST_STOP for doing reset instead of entering STOP mode and nRST_STDBY for doing reset instead of entering Standby mode) I get the impression that it is really not entering Standby mode but Stop mode.
The reason I get this impression is that if I reset the nRST_STDBY bit in the option byte field, that makes no difference, it still goes to some kind of low power mode for 10 seconds, and then it is woken up by IWDG.
But if I reset the nRST_STOP bit, there is no sleep period of 10 seconds, it immediately resets, and the Low Power Reset flag in RCC_CSR is set.

I use the PWR_EnterSTANDBYMode() -function provided with the ST-lib to enter Standby mode, and when looking at that code it looks correct according to the reference manual.

Anyone else that recognizes this behavior ?

br Håkan