Game Input MultipleXer

Without touching my soldering iron or a exacto..it seems as though I have bypassed the onboard vreg.

Schematic appears to show the 3v3 pin on the breakout board is connected to the micro. Didn't see any diodes.

Feeding 5v from an Arduino Mega (just whatever I happened to have within reach that has a 5v reg) to the 3v3 pin and ground, it appears to run the micro & I am able to access the bootloader for flashing.

Now, while this worked for testing - if I plug in the USB side, the reg will still be feeding that line 3v3 while I am feeding it 5v from somewhere else..probably not a HUGE issue but now that the micro is powered, I can d/c (cut) the vreg.

So..I should be running at 5v now..my Arduino should also be good for 5v UART so I might try that too..

When the adapter is flashed with the firmware and then plugged into anything but before GIMX app connects via UART or anything - will that host device see any type of USB device?

I would guess that it should see whatever device I flashed firmware for and then gimx connects and feeds the data to make it work?

Or does GIMX need to connect/init the micro before any usb shows up?

Even running at what should be 5v now (tried a few diff ways, there is an disable pin for the onboard reg, disabled it and feeding it regulated 5v) I am getting nothing via UART and nothing is detected via USB when plrugged into laptop. Testing with emug27pc firmware for now I guess.

Okay..

So I have applied 5v directly to the output pin of the onboard 3v3 reg.

Disabling the internal reg by pulling the enable pin down does disconnect usb power. Was able to hit bootloader button and program it at 5v even..

Still see no response via USB when plugging in (not detected as anything at all) and I am getting nothing over the UART either from the gimx app

I just attempted to, and successfully flashed the firmware using the gimx app alone instead of from the command-line w/avrdude. Seems like it basically did the same thing but figured it was worth a shot..

No change..

I also pulled out my multimeter..(it's -20 outside and it was in the car) and verified the micro is definitely being fed 5v now.

So my board is running at 5v. I have tried two different USB UARTs, an ftdi 232r with and without a voltage divider on the RX and another cheap one I use with my car's ecu which works at 5v thus the USB UART should work at 5v no problem, I am pretty sure it is a 5v version.

Either way, unless I press the button to switch into bootloader/flashing mode, the board seems to do nothing..

What's my next debug step? Is it possible the micro may not work but still be flushable? I suppose I could whip out the stock arduino style firmware and see if it'll do anything but..I don't see any reason for any issues like that..

Ideas?

Current status:
1. My 32u4 board is running at 5v regulated (not powered from USB) and the onboard 3v3 regulator has been disabled.
2. Able to flash the microcontroller with GIMX firmware BOTH from the command line w/avrdude and through the GIMX app. Flashing succeeds both ways and appears to write the same amount of bytes each time. I have tried a few but am using g27pc right now for testing - I simply want to see the USB side enumerate as a device on my PC
3. Have tried two different USB/TTL adapters. One is a 232r on a breakout board with LEDs, I can see blinking as GIMX is sending it's packet every second as GIMX tries to connect, I do not see any blinking on the RX light, except a brief pulse when I power up the micro which I assume is noise. The other is an FTDI of some sort and should work at 5v fine as I use it for another 5v application - I also just measured 5v out at it's VCC line, I'd guess this means it's a 5v version but it could be cheap enough to just have that directly connected via USB.
4. I have tried with and without a voltage divider on the micros output to step the 5v logic output down to 3v3 for the ftdi's input. Both USB/TTL are verified working through loopback. Considering I can (and many many people have) used a voltage divider to lower the 5v logic to 3v3, I don't think this would be an issue, as for the output to the micro, the threshold for on should be about 2.8v so it shouldn't need anything either.

I would assume that I should see *something* on the USB side when plugged in right? It should at least enumerate and stay dormant until I load the app and feed it data?

Or will it not even enumerate unless it is told to?

The atmega32u4 side of the adapter will only enumerate after clicking on "Start" in gimx-launcher.

Okay. Thanks for clarifying that.

For some reason I am still getting no UART comms though even when running at 5v..ideas?

I'm not sure your ft232r is 5V tolerant.

It should be and the one that isn't was stepped down.
I can put a scope on the lines if you wish but I get the feeling something else may be up...

It's definitely a hardware issue. The recommended hardware works flawlessly.