STM32 OSC32 output usage

[gokcerb]

Posted on December 19, 2010 at 21:50

STM32 OSC32 output usage

[Tesla DeLorean]

Posted on May 17, 2011 at 14:18

Most likely the low voltage/power, and loading of the crystal. Check the Vpp and loading requirements of your system, and very short trace lengths.

Can't you use a copy of the 32 KHz presented at the MCO pin?

Notwithstanding the fact that 32.768 KHz watch crystals should cost pennies.

[gokcerb]

Posted on May 17, 2011 at 14:18

Hi Clive1,

 Thank you for the information. Actaully, for MCO output, I've read the STM32 reference manual and as far as I understand MCO clock output could be possible for high speed clock and PLLs, therefore, for my understanding it won't be possible to get 32 khz clock output from MCO. (may be it could but I do not know how to do)

 Well, programming timer and getting a near 32 khz counter and interrupt may solve my problem.  

  For clock crsytal, I think, master clock signal must be syncronized with CPU , I will check it, but most probably, you are rigth,  external 32 khz clock connection may solve problem instead of using STM32 clocks or timer.

Regards

Gokcer

[pablovivan]

Posted on June 23, 2012 at 13:50

Hello to everybody,

I am trying everything to be able to use the PC14 and PC15 pins as digital outputs, but I can't get it at all. 

Obviously I'm not using the LSE.

Both pins aer conected  to two MOSFET gates respectively, so there is barely power consum (I'm not trying to drive a LED or anything like that)

The information found in the documentation is very, very poor and in the forums isn't more useful.

I have assumed that the LSE is off once I turn on the uC and just defining the pins as outputs and using the GPIO_SetBits doesn't work.

I have assumed that the LSE is on once I turn on the uC. I inicialized APB1_PWR clock. I enabled the RTC access and I disabled the LSE clock security system and I turned off the LSE explicitly.

I think I've tried all the likely combinations and I keep on failing. I`m missing something but I dont realize what is it. I hope you could help me. Thanks in advance.

Regrads.

[domen23]

Posted on June 26, 2012 at 09:24

Did you enable GPIOC clock? Do the other pins work? Did you check it with a scope/multimeter directly on the pin? Does it work when configured as input?