# Accessing hardware registers and assembly code on nonAVR architecture

**URL:** <https://forum.arduino.cc/t/accessing-hardware-registers-and-assembly-code-on-nonavr-architecture/1153535>\
**Category:** UNO R4 WiFi\
**Created:** [July 31, 2023, 1:17pm UTC](https://forum.arduino.cc/t/accessing-hardware-registers-and-assembly-code-on-nonavr-architecture/1153535 "2023-07-31T13:17:04Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![Merlin513](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Merlin513](https://forum.arduino.cc/u/Merlin513)\
**Post date:** [July 31, 2023, 1:38pm UTC](https://forum.arduino.cc/t/accessing-hardware-registers-and-assembly-code-on-nonavr-architecture/1153535/2 "2023-07-31T13:38:31Z")

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Not sure about assembly as I don't use it much for the boards I used (mainly arm) but there has been quite a bit of discussion on accessing I/O registers:

[Compatibility: digitalPinToPort and digitalPinToBitMask - UNO R4 / UNO R4 WiFi - Arduino Forum](https://forum.arduino.cc/t/compatibility-digitalpintoport-and-digitalpintobitmask/1150949/11)

[AVR Compatibility: PORT and PIN registers? - UNO R4 / UNO R4 WiFi - Arduino Forum](https://forum.arduino.cc/t/avr-compatibility-port-and-pin-registers/1150693/14)

This is a good one:  
[digitalWriteFast with UNO R4 - UNO R4 / UNO R4 Minima - Arduino Forum](https://forum.arduino.cc/t/digitalwritefast-with-uno-r4/1145206/28)

There was another one to a library someone had put together but I can not find the reference right now. If I come across it I will post it here.

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