Teensy 4.1 Implementation

[Shiny Saana]

Hello!

I'd like to implement support for emulating the teensy 4.1 board (

https://www.pjrc.com/store/teensy41.html) to QEMU.

I'm honestly quite lost as to where to start at the moment, since I can't really find any emulated Cortex-M7 that would be close to that board already implemented.

I asked around on IRC, and I was redirected to those two mailing lists, for guidance, and also as writing code without maintainers approval would be pointless.

Thank you!