LSE and STOP mode

[Kuikui]

Posted on October 16, 2010 at 16:41

LSE and STOP mode

[Tesla DeLorean]

Posted on May 17, 2011 at 14:11

Ok, built something similar for the VL Discovery board. With a one second period it works fine with and without the PWR_EnterSTOPMode()

I suspect your use of the 64 Hz / 16 ms period is a problem, my guess would be the restart time (HSI+LDO) exceeds 15-16 ms so the period of the LED toggle pushes out. I haven't had the time to measure the exact time, or find a good cite in the manual, but give it a try. Also using the following code in a tight loop on the Discovery VL + ST-LINK board causes the JTAG connection to FAIL and makes it impossible to communicate with. I'll need to go unbrick one of my boards. PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);

[js23]

Posted on May 17, 2011 at 14:11

You should use RTC_WaitForSynchro() after wakeup from stop mode before acessing RTC registers. Maybe this helps?

[Kuikui]

Posted on May 17, 2011 at 14:11

I'll try to measure the wake-up time of HSI + LDO.

But I would be very surprised if it would take more than 16ms !

[Kuikui]

Posted on May 17, 2011 at 14:11

Datasheet says :

- wake-up from stop mode + ldo_low_power : 5.4µs - HSI startup time : 1 to 2µs we're are really far from the 16ms ^^ clive, did you test your Discovery VL at 64Hz ? Did you manage to reproduce my issue ?