Issues with latest batch of Itsy Bitsy M4

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

Issues with latest batch of Itsy Bitsy M4

Post by tykockin »

Hey!
So Ive been using these little workhorses for a while in a project that has an instrument amp, a motor driver, a rotary encoder, and a 1.8" TFT display on the ST7735 IC. Everything has been fine...until today. This batch of I-B-M4's cant deal with the rotary encoder. I thought maybe it was my PCB, but if I take the whole thing apart and jumper only the encoder and TFT, it still won't work. It cant understand the difference between a detent and the button press. I initially blamed my encoder and the display, but I troubleshot everything with a working unit -- and theyre all fine.
It's almost like the pull-up resistor isn't there? OR something?? Anyone else having trouble?? This is the case with 2 of the 10 I just bought. I am hesitant to solder on the remaining headers on the other 8 just to find the same problem. Again -- everything works perfectly well with the exact same Arduino code on a I-B-M4 bought a few months ago.

Thanks!

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mikeysklar
 
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Re: Issues with latest batch of Itsy Bitsy M4

Post by mikeysklar »

No changes in the last two years to the ItsyBitsy M4 PCBs design.

https://github.com/adafruit/Adafruit-It ... xpress-PCB

The bootloader being different would be my first guess. Have you normalized that factor by updating the old boards or backdating the bootloader on the new boards? The new ones are probably shipping with v3.13.0

https://github.com/adafruit/uf2-samdx1/tags

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tykockin
 
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Re: Issues with latest batch of Itsy Bitsy M4

Post by tykockin »

Thanks; I will give this a try. Interestingly enough, the boards I got that don't work have v2.0.0 on it -- which I'm guessing MIGHT have something to do with the issue! (c:

UPDATE:
Alas, the updated 3.13.0 bootloader didn't seem to fix the issue, so I am going to try a few of the older ones and see what happens. Oddly, the display and encoder work completely fine on the Metro M4 Express, but can't seem to get their stuff together on the Itsy Bitsy.

UPDATE2:
Well, a simple fix seems to do it -- I moved the switch of the encoder off of pin 13, and swapped with the DET pin. The encoder doesnt read all that great too, furthering my belief that it's something with the chip or the library and not with my other hardware.
Now, I've NO idea why this fixed my issue, but I can only think it goes back to another problem I had where Pin 13 could not be used as a bridged reset pin. So, in short, something is weird with Pin 13 on what appears to be a level beyond the scope of what I can muster. Any thoughts on this one? I know the easiest fix is "just dont use 13 for that", but now I've 2 key function s that Pin 13 can't handle well and zero idea as to why.

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mikeysklar
 
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Re: Issues with latest batch of Itsy Bitsy M4

Post by mikeysklar »

It looks like pin13 is tied to a red LED.
#13 - GPIO #13 can PWM, is connected to the red LED next to the Reset button
https://learn.adafruit.com/introducing- ... wE#pinouts

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tykockin
 
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Re: Issues with latest batch of Itsy Bitsy M4

Post by tykockin »

Fort sure...but any idea why that's precluded me using it as a reset and a switch? Ive even removed the resistor and LED from a board, and still not fixed any of the issues I've had with Lucky Pin 13.

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