STM32F413VH RTC using LSI

[sushanth]

Posted on March 19, 2018 at 12:53

Hi.

We are using STM32F413VH in one of our projects. We were planning to use the RTC peripheral with LSI as clock source to get timestamps and check weather the tasks are running periodically. We are planning to use RTC as it is independent of the system clock.

My question is how stable & accurate is the LSI? Can we use it to accurately measure time?

Thanks in advance.

[waclawek.jan]

Posted on March 19, 2018 at 22:07

My question is how stable & accurate is the LSI?

It's very bad in this regard. It's primary purpose is to wake it up the mcu from very low power consumption modes in  applications where timing is not an issue.

JW

[sushanth]

Posted on March 20, 2018 at 13:46

We were planning to use the RTC for clocktest for safety purposes. Can we go ahead with LSE?

[henry.dick]

Posted on March 20, 2018 at 14:30

The data sheet has the answer for your question.

If your mcu is always running, consider using the main oscillator for time stamping.