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ter · 2013-03-01

Posted on March 01, 2013 at 13:45HelloWe use the STM32F2 for a project and have problems with the LSE crystal.We use a Citizen CMR200T crystal (32.768kHz, CL=6pF, Farnell Nr. 1652560) wich has a gain margin of 6.1 (according to the ST application no...

ter · 2013-03-01

Posted on March 01, 2013 at 14:09If i see it right, you have a clock frequency of 4Mhz With a typical pin capacitance of 5pF you have 15pF (uc + tbx.. + at45..), lets at another 5pf for the pcb track so we have 20pF. I thing with this capacitance, t...

ter · 2013-03-01

Posted on March 01, 2013 at 13:38Hi If someone is interested, i made measures regarding this issue. Even after calibration, the LSI's frequency changes with temperature, therefore not accurate for most RTC applications Measurement frequency shift ov...

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STM32F2 LSE RTC crystal issue: Can anyone help?

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