I found out the issue, it's newbee one :) I enabled interrupts early and it ISR is called before I initialized a device, working with that device caused an error. Thanks for the response and the blog!

Hello, thanks for the article! I'm trying to set a low value for timer it panics, e.g. timer.start(100.millis()).unwrap(); I'm using STM32F103C8T6. Any thoughts on why?