Hi All, new megadrum build, looking for some advice!

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Hi All, new megadrum build, looking for some advice!

Postby midnightlamp » Sun Oct 22, 2017 3:41 am

Hi All,

Just going through a megadrum build and think I have things somewhat sorted....but am just not quite there yet.

I built the board from:
viewtopic.php?f=3&t=1623

Pics of the board assembled are here:
https://imgur.com/a/RqGMR

I used an ATMEGA644-20PU (20mhx xtal), with the added EEPROM chip, and went with a PIC18F2550 (12MHX xtal)

To get the pic programmed, I used a PICkit 3 (and MPLABX) and uploaded firmware from 7/18/2011, posted on the main page (pic18f2550usb_12MHz.hex). Used the PICkit 3 as I don't have a COM port kicking around.

I chose to get the ATMEGA from digikey as I'm in canada and didn't want to wait to order an atmega from dimitri unless I was sure the rest of this was going to work (the chips are so cheap I figured I'd get going with this one, and order one with the protected bootloader ASAP).

USB to Midi works fine it seems as the device shows up, I can open it up in the newest version of megadrum manager and I can get it to connect and show up with two midi options each for in/out.

The atemga however poses to be a challenge. I built an ISP cable, and found a computer with a parallel port and installed PonyProg. With it set to a 644, I couldn't get the probe in the program to work, but when I used "write all" with the programmer set to AVR ISP I/O and the correct LPT, it writes, verifies and all that with no issues. I've tried loading megadrum644_20_56_20091217.hex and megadrum644_20_56_20100516.hex. Both result in the megadrum loadding up Dimitri's name up front and then go to the VU meters, but neither can access the bootloader with the left boot option. I also tried just the bootloader from: viewtopic.php?p=7281 but it did not seem to work either. Any ideas of what I should be trying? Both also show up in MDM but only the FW version shows up (the MCU says: unknown). Any attempt to get parameters results in "get config COUNT Sysex Timeout". I wanted to try both MFWupdate and Midi-OX but my understanding is both need me to be able to boot into the bootloader!

EDIT: In case it helps, if I hold down left, nothing happens it just gets stuck on the copyright screen. It's not the same as leaving it alone (where it goes into the VU screen). As a seperate issue maybe, the VU screen has all the bars maxed out, and I'm getting midi events scrolling constantly in MDM.

Thanks in advance....!
midnightlamp
 
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Re: Hi All, new megadrum build, looking for some advice!

Postby dmitri » Sun Oct 22, 2017 7:57 pm

There is no point in a bootloader with the last unencrypted firmware - you will not be able to upgrade to any newer firmware version anyway.
dmitri
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