STM32F2 RTC coarse calibration seems to have no effect
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‎2016-02-11 1:29 AM
Posted on February 11, 2016 at 10:29
Hi,
on a STM32F207 I want to use coarse calibration but it seems to have no effect. - I changed PRER to PREDIV_A = 63 and PREDIV_S = 511 and print it out on a UART after reset. I changed to these values to have a better calibration resolution. This is how I understand chapter 22.3.9 of STM32F205 207 ref manual. - Still I have 512 Hz at the calibration output, though chapter 22.3.12 in ref manu implies that the frequency depends on PREDIV_A, following this I would expect 1024 Hz - for several weeks I changed CALIBR but always have the RTC running about 20 ppm too fast (eg. 12 sec in 6.8 days). Now I reached CALIBR = 0x9F, I also print this out after reset. As far a I understood I should have a slow down of the RTC of 31 ppm with these settings, but no success. Is there any setting I need to make to enable coarse calibration? Or do I need the standard values in PRER? Any other ideas? Thanks a lot Martin #rtc-stm32f2-calibration
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‎2016-02-14 11:52 PM
Posted on February 15, 2016 at 08:52
just pushing this up again
Any ideas ? Does anybody have a good experience with coarse RTC calibration? I would be glad to hear some details about it. Thanks a lot MartinOptions
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‎2016-02-15 3:58 AM
Posted on February 15, 2016 at 12:58
Would suggest you chat with your local FAE
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Up vote any posts that you find helpful, it shows what's working..
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‎2016-10-14 1:58 AM
Posted on October 14, 2016 at 10:58 Hi Mr M from G I'm facing the same problem do you have any news for us? Thank you very much! Cheers B from S
