Atmega1284 gone crazy

[BazzMasta]

Hi everyone.
I need some help.

Since the last few weeks I can't play my megadrum because, I don't know why, some inputs are triggering all the time, very fast, without sense.
I have an ATMEGA 1284. I've upgraded to the 20151030 (20Mhz) but the problems keeps going.
I've also tried to downgraded, change configurations, default config (power up + right button), the hot piezos options, usb powered cable... nothing works. I have no clue about what to do next.
After loading the default config, when I change one option it begins to triggering again. Even without doing anything, after 2-3 minutes in calm, there they go again.
It's kind of frustrating.

I attach one photo where you can see wich inputs are doing wrong.

Thank you in advance.

[airflamesred]

Do you have pads plugged into these inputs?

[BazzMasta]

No.
As far as I can remember, I don't have my e-drum in my house and I haven't played for a month or so, they send the 53 and 55 note, but there's nothing plugged in.
I also made a "hard reset (default config)" with and without inputs plugged. The result is the same.

[ignotus]

Looks like the multiplexer those last 8 inputs go into isn't grounded properly. I know I keep dishing out the same advice but it looks like a likely culprit.

[airflamesred]

If you have upgraded the firmware make sure you re load your own settings.

[BazzMasta]

Hi once again.

@ignotus: The soldering has never never been a problem in this module, at least not for the last 3 years that I've been playing with it. In any case, I've already checked all the wires, jacks, soldering,... Anyway, I will check it again.

@airflamesred: After upgrading I loaded my saved settings, didn't work. Then I also tried with the default config (power up + right button). And all the possibilities I know... downgrade, load different presets, upgrade again + presets,... nothing worked out.

Thanx to you all, and I hope anyone can find the answer.

[ignotus]

The reason I suggested that is because each multiplexer has 8 associated inputs - it seems likely that there is a physical short/break related to that multiplexer as its 8 inputs are the ones misbehaving. I'd thoroughly check all connections around it for continuity. Hairline cracks years after doing the soldering job are not unheard of - it's happened to me.

[dmitri]

This is definitely a problem with one of the MUXers. You can figure out which one by setting MaxInputs to the minimum and then start increasing it and see at what MaxInputs it starts firing.

[BazzMasta]

Hi again.
This is weird.

I tried to set the mininum inputs and then increase them to figure out wich one is firing as you suggested Dimitri.
At first attempt, I saw that the module starts firing with 40 inputs but not all of them. With 56 inputs working it goes as the photo I attached in the first post. Ok then, after a few more test, and sawing that all seemed to work out, I went back to the 56 and nothing happens, no firing signals.

But my surprise was that at this point, the hi-hat is sending a 0 note when is set to 46. I tried again with 38 inputs, 56, usb powered cable, usb cable as usual,... once, I don't know why it was right sending a 46 note, but all the others were zeros.

I must also say, that I can't update firmware (upgrading or downgrading) via Megadrum program (java based), I always received a message that says "megadrum is not responding". The only way I have to change the firmware is via MDupdate.exe.

Thanx again for any help I can get.

[dmitri]

From the description I can only suspect that there is an intermittent short or a break around the 6th MUXer (inputs 41-48).