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What is the connection between RTCCLK and Sysclock?

HCohe.1
Associate III

I am using hw_timerserver and sequencer for BLE. I added additional tasks to the sequencer for my application. It appeared that my tasks are running much too frequently, so I looked into the clock configuration of the RTC and found that WUCLK was driven by HSE and did not have the WU Clock and WU Counters configured properly. I switched the clock source to LSE, with WU clock & counters set to RTCCLK/16 & 2, for proper operation in Low-power modes. I then found that Systick was slowed down considerably. Any ideas?

2 REPLIES 2
HCohe.1
Associate III

I attached the .ioc file. Can anyone explain why Systick is now slow as molasses after switching RTC to LSE? It was okay when HSE was used.

Christophe Arnal
ST Employee

Hello,

There is clearly no connection between RTCCLK and Systick.

I would check the configuration of the Systick. For an unknown reason, I believe it has been wrongly setup.

Regards.