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Using Pin 13 for Reset Doesnt Work
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Using Pin 13 for Reset Doesnt Work

by tykockin on Mon Jun 07, 2021 3:39 pm

So, I was trying to connect Pin 13 to the RESET pin and use it to reset the ItsyBitsy using code. I've done this with great success in another SAMD51 (Metro), but I think I must've used a different pin...Anyway, bridging RST and 13 basically keeps the board in constant reset, no matter what I do. Other pins work just fine as the "reset" pin, just not 13.

Why?

I designed a PCB to be controlled by the Itsy., and I dont want to have to re-fab them if there is a simple fix for this -- other than using another pin of course. Thanks!!

tykockin
 
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Re: Using Pin 13 for Reset Doesnt Work

by dastels on Mon Jun 07, 2021 9:41 pm

Hmm. D13 is connected differently with the two different MCUs. Also, in both cases it's connected to a LED through a resistor. on the MetroM4 that's a 1K but on the ItsyBitsyM4 it's a 2.2K. TL;DR D13 is different on the two boards. My approach would be to use a digital pin to trigger a one-shot timer that generates a reset pulse.

Dave

dastels
 
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Re: Using Pin 13 for Reset Doesnt Work

by tykockin on Tue Jun 08, 2021 12:05 pm

Cool! New PCB it is. Such is life! I removed the resistor to break the circuit to the LED and it didn't help either. Time to find another digital pin to use. This brings up another question though: it appears A4 and A5 can be digital I/O as well? How does one assign them as a digital pin instead? And for that matter, is it possible to re-assign any of the other pins to digital I/O? Normally (well, on other duinos) everything digital has a number and you have to look up what is also a dedicated SCL, SDA, MOSI, etc....but they're labeled on this board. How does one repurpose these pins, if possible? Thanks!

tykockin
 
Posts: 5
Joined: Thu Apr 15, 2021 2:10 pm

Re: Using Pin 13 for Reset Doesnt Work

by dastels on Tue Jun 08, 2021 2:23 pm

You can often repurpose pins by routing I/O functions in the MCU to physical pins. From what I can tell, it's buried in the libraries. Things like analog functions seem to be available only on a subset of pins.

Dave

dastels
 
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