Powering two ProMicro via RAW, same time USB, fried?

Hello folks!
Tried to dig around, but didn't get a good answer, so figured I would ask here.

I have a ProMicro. Was programming it just fine. I have a 5V DC power supply with plenty of current. I connected it to RAW and GND. Seemed to work fine. But after messing around for a bit with it connected to the USB port and with RAW powered from the power supply, it isn't communicating to the IDE anymore. Can't upload a file, sometimes doesn't even show up on the Port list. Sometimes I get a warning on Windows about "USB device not recognized".

Could I have fried something having RAW powered while giving it USB power? It seems to pass power through RAW when under USB power, and I don't know if that is causing a problem.

Also, I was attempting to power 2 boards at the same time via RAW pins to the power supply. Anything funky that could have happened there? Again, beefy enough power supply for what I am doing.

Edit: Figured from below I had specific questions, so putting it in the main body:

  1. Can I have power to RAW and power via USB at the same time?

  2. If RAW power is connected or disconnected while under USB power, can this fry a chip?

  3. Will a voltage regulator from PS to RAW protect the controller from the above 2 situations?

Cheers!

Did you tried to disconnect the power supply and program it directly through the usb port?
It may occur that the power supply isn't a stable 5V supply voltage. that's the reason why i always use a voltage regulator and use the regulator to the 5v on the system.
This is the thing i used on all of my 5v project's, but be warned that you have to figure out how to set this up correctly.

So first step's first, what i would do is disconnect it from the power supply and try to flash the new sketch to it. if that work's, your usb to tll converter chip on your pro micro is just working fine.

I have tried with the board completely disconnected from the circuit, and only powered via USB. One throws the error, the other one doesn't even get to that point, doesn't even try to connect.

Perhaps I do need a better regulated PS, but this one seemed like it was fairly stable. What I am trying to figure out is:

  1. Can I have power to RAW and power via USB at the same time?

  2. If RAW power is connected or disconnected while under USB power, can this fry a chip?

  3. Will a voltage regulator from PS to RAW protect the controller from the above 2 situations?

Well i don't know the answer on this couple of questions, but i use multiple nano every's.
And as far as i know it's stable for me, i normally use 12V on vin pin. and then use the usb connector to flash the new sketch to it without a flaw.
Then i also use a Power regulator as a backup if the one onboard just crashes.
So from this pont i can clearly say that with an nano it is indeed protected.
But i've had also one that wasn't that ok, and indeed that give's me some error's but this had to with a header pin soldering that i had done. This had i done clearly too hot. and that fried the chip for me.
So in my opinion it should work.

The only thing that i can find is that an 32u4 is an older chip then a uno has. the chip uses a minimum voltage of 4,5V. and the atmega 328P uses a minimum of 1.8V.

But that doesn't seems to be it. maybe later today i wil dig in to it a bit more to find out what happends.

Does the power LED still come on?
There is a diode between the USB power and the RAW input, so that would block power from USB as long as the voltage into RAW was 5 volts or more, but there is also a bypass jumper to feed USB power to the output of the voltage regulator on 5 volt boards. Might have a damaged voltage regulator, but I doubt the 32u4 chip would have any damage.

Were you programming the board with any type of sketch that would affect the USB, such as a keyboard or mouse emulator? The board does not appear to have a RESET button, you might try wiring up one externally so you can double-tap the reset to put the board into bootloader mode. Worst case, reprogram the bootloader and see if that helps.

david_2018:
Does the power LED still come on?
There is a diode between the USB power and the RAW input, so that would block power from USB as long as the voltage into RAW was 5 volts or more, but there is also a bypass jumper to feed USB power to the output of the voltage regulator on 5 volt boards. Might have a damaged voltage regulator, but I doubt the 32u4 chip would have any damage.

Were you programming the board with any type of sketch that would affect the USB, such as a keyboard or mouse emulator? The board does not appear to have a RESET button, you might try wiring up one externally so you can double-tap the reset to put the board into bootloader mode. Worst case, reprogram the bootloader and see if that helps.

The power LED turns on for both when plugged in.

Nothing affecting USB. PWM through the correct outputs, not even using any inputs. Simple program as far as folks here are concerned.

Wired up a RESET button. Clicked it once. Computer recognized it as COM6 (which is correct). but 5 seconds later, no longer showing up on the Device Manger list. If I click Reset again it happens again.

Double tap, same issue and timing.

The one that throws up the "USB device not recognized" error has a second LED that turns on the moment that the error appears and goes off the COM list. Second MicroPro doesn't do that with the LED, but doesn't pop up the error either.

EDIT:
Found a "fix", but I don't like it. Made an empty program, hit Upload at the same time I hit my RESET button (otherwise would disconnect before the upload finished). Took a few attempts, but got the empty program to load. Now it isn't dc'ing. Was able to load my big program no problem. Runs. Able to remove from USB, plug back in, still works. For one of them at least. The one that was giving the USB error. The other one stays connected but sticks during Upload.

Oh, that just sounds like you uploaded a bad sketch that hoses USB functionality. Upload a clean skeych during the few seconds that a port appears after reset (you need to time it so the port is present at the point during process of upload when it shows the size of the compiled sketch - right after that it attempts to upload). Code that hangs the microcontroller or breaks USB more directly (most often, these sorts of problems are writing off the end of an array). That's the price you pay for native USB - if you don't need native USB functionality, I always advise using a board that instead has external usb-serial adapter for uploads, so that there is nothing you can do upload to it that will prevent uploading a different sketch.

5v on RAW - thats the input to the voltage regulator, isn't it? Which has like, 1.xv dropout? So if you power with 5v on raw, you'd only be running at 3.x volts when running from external supply...

Edit: Oh, I see you found that solution. That is the correct solution for dealing with a bad sketch that has broken uploads (the alternative is reburning bootloader with an ISP programmer). Does the other board appear as a different port when you press reset? If so, it probably has the same issue, and the same procedure should unbrick it.

DrAzzy:
Oh, that just sounds like you uploaded a bad sketch that hoses USB functionality.... (most often, these sorts of problems are writing off the end of an array)....

Does the other board appear as a different port when you press reset? If so, it probably has the same issue, and the same procedure should unbrick it.

Thank you for the timing tip! That let me get the second board up and running. I was unaware that this was an issue with USB on board stuff. Good to know, and will avoid that in the future.

Yes, they show a different port. It swaps from COM7 to COM6.

Could you explain the Array issue, or point me where to find more info? Both programs I am running use arrays to access and arrange sets of data. Is there something in arrays I should avoid to keep away from this issue in the future? Or is it just that arrays cause a lot of headache?

Thank you for your answers!