STM32U585 CLOCK JITTER

Dear Sir.

I am using a board equipped with STM32U585 , The main clock is 32.768 khz

see included pic.

PA8 is configured to drive LSE 32KHZ using the command
__HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_HIGH);

PA8 is fed to ECG MAX30001.

On some boards MAX30001 reports pll lock problem.

The signal of 32 khz on PA8 is shown at the attached video.

Setting the parameter __HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_HIGH); to
0 or RCC_BDCR_LSEDRV_0 or RCC_BDCR_LSEDRV_1 makes no change on the jitter

1. Is this jitter is normal.

Please Advise

This topic has been closed for replies.

Best answer by jiangfan

32768Hz jitter is common and normal, while 32768Hz clock long term stability is good in general.

I suppose the "pll lock problem of MAX30001" is not directly link to 32768Hz jitter with STM32U585 or other MCU.

ST Employee

32768Hz jitter is common and normal, while 32768Hz clock long term stability is good in general.

I suppose the "pll lock problem of MAX30001" is not directly link to 32768Hz jitter with STM32U585 or other MCU.

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