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Bricked QTPy...
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Please be positive and constructive with your questions and comments.

Bricked QTPy...

by 762spr on Sat Dec 19, 2020 2:28 am

Hi,
I am trying to get a QTPy board working with arduino... It doesn't appear on the boards list so I have been trying with other M0 selections, such as the trinket or feather.

When I plug in the board initially, it is recognized as a QTPy and shows the RGB LED shifting colors. However if I try to upload the program, it either gives me an error or hangs on uploading. After that the board appears to be bricked and is not recognized by windows. Even when trying a blink sketch. After many retries, I eventually got a board programmed and it was talking over the serial port, but as soon as I tweaked the code and re-uploaded, I ran into the problems again...

I have tried with my own sketch and with a simple blink sketch.

So far I have apparently bricked two boards and I really need to get this project programmed before Christmas! Not really sure where to start here, any suggestions?

762spr
 
Posts: 23
Joined: Thu Dec 20, 2018 4:23 am

Re: Bricked QTPy...

by 762spr on Sat Dec 19, 2020 3:35 am

Update: I have seemed to have revived the board by double tapping the reset button and can now upload and monitor the serial with itsy bitsy M0 board selected. It worked for a little while, but now every time it says it uploads, then it hangs, then it says there is no board found on the com port... Sometimes closing out of everything and resetting everything will get it working for a minute, then it stops finding the board again. Very sporadic. The last thing I tried had the board constantly resetting and connecting/disconnecting to my computer. This was after setting the serial baud rate to 115200.

762spr
 
Posts: 23
Joined: Thu Dec 20, 2018 4:23 am

Re: Bricked QTPy...

by 762spr on Sat Dec 19, 2020 8:13 am

Another update: The board is still acting strange, but I have gotten it working well enough to move forward. Pin names are off, but I have a feeling it is because I am using the wrong board definition. Is it possible to get the correct one for the QTPy?

I believe the main culprit was the servo I was trying to drive. I read multiple places that a micro servo should be fine to direct drive, but that doesn't seem to be the case here and it was causing the chip to brown out and reset. when powered off an external power supply, it works great... the only problem is I NEED to get power off of the USB, I can't have an external power supply hooked up to this thing, and that would also require redesigning the entire enclosure which is currently made to get power for the whole system off the USB port...

Is it possible to tap the incoming side of the 5v before it gets routed through anything that would limit it's current? like directly off the back of the USB C connector, or the left side of the diode at the top? Looks like there are also two pairs of thicker contacts on the connector, and the inner ones are 5v? I know this isn't ideal or best practice, but would it kill anything?

762spr
 
Posts: 23
Joined: Thu Dec 20, 2018 4:23 am

Please be positive and constructive with your questions and comments.