PIC won't program correctly

[LogiK]

Now that I've got the digital board working, I'd like to get it cooperating with my computer!
After plugging the Megadrum into the USB to provide power, I used Picprog (a Linux PIC programmer) to flash the PIC with the latest firmware (MegaDrum USB MIDI Firmware 18F2550 12MHz V2.hex). The burning process works great until it gets to the configuration/fuses, at which point Picprog errors out with a couple of verification failures. I used the "--erase" option before burning, which is supposed to clear out everything on the PIC first. So far I've had similar outcomes using Windows with some other PIC programmers.

Anyway, here is a dump of what's on the PIC currently:

after.hex

Any suggestions? Is it safe to fully reattach the USB module (it's just connected to VCC and GND right now) or is this going to cause headaches for my computer?

[dmitri]

After loading the original firmware and your dump into WinPic and then dumping to two files for comparison I only see difference in the 'configuration memory' byte:

Code: Select all

$ diff dumped_orig.hex dumped_l.hex
2081c2081
< :0E000000320E3F1EFF8085FF0FC00FE00F4045
---
> :0E000000320E3F1E008085000FC00FE00F4043


Why it is different from original after you programmed your PIC I don't know. This is how WinPic shows 'configuration memory' setings with the original firmware and your dump:

orig.png

after.png

How it effects MIDI USB I don't know. Maybe Synthex can advise on this.

[Synthex]

Your dump and the original Hex are the same ! You just have just a value in EEPROM ... (see with WinPic800)

You can test your USB module with your computer.

[LogiK]

OK, I re-attached the USB board fully and plugged the MegaDrum in. The good news is that I am now getting the full 5V from USB (as opposed to .75V the last time I had the USB board attached) and I did see a "MegaDrum MIDI USB" device show up in the hardware info screen. The bad news is that this was short-lived: the MegaDrum appears to activate, but then vanishes after a few seconds. Just seconds later, it "activates" again and that cycle repeats endlessly! Just to be thorough, I'll give it a try in Windows to see if that makes any difference. In the mean time, does anything come to mind about why it would be doing this?

edit: The MegaDrum is detected -- and remains that way -- in Windows XP... I wonder what the hangup is with Linux? Maybe I'll find someone with a similar problem on the Ubuntu boards.
Thanks again, guys for your help!