RTC clcok slow when turning on LTDC

[aabba.1]

Hi,

I am using a custom board to do some application (https://www.waveshare.com/openh743i-c-package-b.htm). On this application I should turn on LTDC (to use it with touchgfx) and I am also using the RTC.

When I am only using RTC alone, the RTC clock is correct and I can see it on pin MCO1 via my oscilloscope a good shape.

But when I turn on RTC and LTDC, the shape is wrong frequency (clock is slower 10seconds) is different then 32.768Khz and dutyCycle is different from time to time.

Can I fix this issue via S/W?

[waclawek.jan]

Check if there are any LSE-related errata (maybe PC13-related?).

Try different LSE drive strengths (you may need to reset the backup domain between attempts).

JW

[aabba.1]

it work with different LSE drive strengths... thank you