Reprogram MCU Nation N32G455 Series

[MTBACHO]

Hello!!  I have been reading across the forum many interesting topics!
I got mesmerized by the MCU posts! After some reading, and still a completely unexperienced, I started thinking a way to solve a rather odd problem I have with my 3D printer main board. It is from a Voxelab C2. As mentioned it  has a Nation 32 bit MCU, ARM Cortex M4 kernel, 144MHz. Datasheet as follows:
https://www.nationstech.com/uploadfile/file/20220906/1662453066413965.pdf
The problem that I am experiencing is that the printer is interpreting that Enter button or OK button is always depressed. The rotary encoder and button are not the problem as I tested it with a multimeter. I have found that the pin 27 designation PB1 on datasheet is short to ground. Following the trace of the board goes to the header to screen and button. My question is. if I fully reprogram the MCU, can I use or designate another PB pin for the enter button function and recover the functionality of the board.
Any Idea if this method could work.
Many many thanks in advance!

[abyrvalg]

Sure, why not? The firmware source code appears to be open, so you can reassign that function to some unused pin, build the firmware, cut and rewire the PCB track to that new pin, flash the modified firmware. Or just buy a new MCU (the firmware page lists several compatible chips), replace it and use the original fw as is. Whatever is easier for you.

[wraper]

I would order a new MCU instead of bothering with modifying firmware. It's less than $2 on aliexpress.

[voltsandjolts]

Nation 32 bit MCU, ARM Cortex M4...
I have found that the pin 27 designation PB1 on datasheet is short to ground.

It's a little unusual for an MCU input to get internally pulled low, but possible with ESD damage.

Check wiring and PCBs traces leading to MCU. Do a close visual inspection with x7 magnifier or a microscope on the MCU itself; check for little solder bridge or some other conductive short to the next pin. Clean area with IPA. If removing the MCU, first try lifting just that pin to test it.

[MTBACHO]

Sure, why not? The firmware source code appears to be open, so you can reassign that function to some unused pin, build the firmware, cut and rewire the PCB track to that new pin, flash the modified firmware. Or just buy a new MCU (the firmware page lists several compatible chips), replace it and use the original fw as is. Whatever is easier for you.

That is exactly what I had in mind! to cut the trace and use another pin. I have found a similar schematic for a Aquila printer. Pin allocation is a little different. Happy to know it is an option. Where is compatible chip list that you mention? On the datasheet?

Nation 32 bit MCU, ARM Cortex M4...
I have found that the pin 27 designation PB1 on datasheet is short to ground.

It's a little unusual for an MCU input to get internally pulled low, but possible with ESD damage.

Check wiring and PCBs traces leading to MCU. Do a close visual inspection with x7 magnifier or a microscope on the MCU itself; check for little solder bridge or some other conductive short to the next pin. Clean area with IPA. If removing the MCU, first try lifting just that pin to test it.

I had the board under the stereomicroscope and no bridges what so ever. Have not cut the trace yet, bur pretty confident the short is internal. I will update you on that.

I would order a new MCU instead of bothering with modifying firmware. It's less than $2 on aliexpress.

I have it on mind, but wanted to get involved in custom firmware.

[wraper]

Modifying firmware just to keep a cheap faulty part is stupid IMHO. Also if you will need to update firmware to newer version, you will need to modify it again.

[abyrvalg]

Lift that pin and check it for short in unconnected state to be sure. Then you can just rewire the track w/o cutting anything.