STM32H7A3 External Crystal

[Joseph.Paul]

can we use internal 24MHz clock for STM32H7A3VIH6Q host or we should use external? Maybe in the future we are going to use USB. Now, just UART and SPI, should I use external to support USB in the future?

[AScha.3]

For better precision (and low jitter) use external crystal. USB anyway needs it .

I recommend an oscillator (i use also) , no trouble with caps etc. ; today not much more expensive than a crystal and the caps.

And a damping resistor (51r) in the clock line, to avoid ringing.

Something like this: 520-2520MV-160-CNT

https://www.mouser.de/ProductDetail/ECS/ECS-2520MV-160-CN-TR?qs=byeeYqUIh0MIhToPrW09tg%3D%3D

or if you want 24 M  : 520-2520MV-240-BN-T