Gastric's MegaDrum build

[gastric]

I'm into checking the board against the schematics. I'm trying to take baby steps so I've started with all of the components that connect to Atmega that deal with programming it.

So I've check the keyboard, ISP cable header, and USB power, and their connections to the Atmega32. I've double checked VCC and AVCC from USB, gnd, Atmega crystal, and ICSP all appear connected (continuity) to Atega32 properly. I'm not able to check total continuity from the right keyboard button to the Atmega due to the 1N4148 but did check continuity from the right keyboard to the 1N4148 and then from each 1N4148 to the respective pin 6 & 7 on the Atmega. As best I can tell at this time all of the physical traces/pins that are required to program the Atmega have continuity and no shorts with other components or traces. The only things I cannot physically test are the actual functionality of the 1N4148 and the 16Mhz crystal.

I'm assuming the crystal would be the first thing to check. The best I could do is swap it for a 20Mhz to see if it would allow PonyProg to communicate with it. Does that sound like the most reasonable next step?

[dmitri]

I'm into checking the board against the schematics. I'm trying to take baby steps so I've started with all of the components that connect to Atmega that deal with programming it.

So I've check the keyboard, ISP cable header, and USB power, and their connections to the Atmega32. I've double checked VCC and AVCC from USB, gnd, Atmega crystal, and ICSP all appear connected (continuity) to Atega32 properly. I'm not able to check total continuity from the right keyboard button to the Atmega due to the 1N4148 but did check continuity from the right keyboard to the 1N4148 and then from each 1N4148 to the respective pin 6 & 7 on the Atmega. As best I can tell at this time all of the physical traces/pins that are required to program the Atmega have continuity and no shorts with other components or traces. The only things I cannot physically test are the actual functionality of the 1N4148 and the 16Mhz crystal.

I'm assuming the crystal would be the first thing to check. The best I could do is swap it for a 20Mhz to see if it would allow PonyProg to communicate with it. Does that sound like the most reasonable next step?

Do not swap it for a 20MHz crystal, Atmega32 is rated for 16MHz and using a 20MHz crystal you're introducing another uncertainty.

[gastric]

I'm focusing purely on programming the ATmega32 at this point. I've checked everything on the schematics related to the ATmega programmer header which is basically 5 pins, VCC via 4 resistors, connected to the keyboard header (and buttons if connected) and Pins 6,7,8,9 on the ATmega. Not a lot of components and traces to check, and they're all solid, no shorts, etc. I see nothing wrong. I've tried two computers with LTP (I have 5 PCs + 1 laptop, and only 2 LPT between them all) and I believe have ruled out the LPT port itself as the issue.

What I don't know is what internal connections the ATmega makes (the ATmega itself must have internal connections between the various poins) and what other components come into play for programming. I've checked the crystal for connectivity on the board, everything is fine. I've confirmed good ground from ATmega pins 11,31.

I'm down to concluding the following:

* I have two bad ATmega32 chips, hence why neither communicates with PonyPROG.
* Some other component required to program ATmega32 is defective. That would be the crystal or 22pF. I'm not sure how to test either for proper functionality.
* I'm simply too dumb to figure this out. Though I don't think that's the case, the fact I can't get this working is causing doubts.

Was hoping for some additional guidance before I simply try to swap parts (crystal, 22pF) and order another ATmega.

[dmitri]

There very few reasons for not being able to program Atmega using an ISP cable:

1. The ISP cable is not wired correctly.
2. PonyProg is not configured correctly.
3. Not powering Atmega while trying to program Atmega.
4. Incorrectly programmed "fuses" in Atmega.
5. Shorts/breaks in the board.
6. Broken crystal/capacitors (can't imagine how it can happen).
7. Broken Atmega.

Also look through these topics:
http://www.megadrum.info/forums/viewtopic.php?f=3&t=510
http://www.megadrum.info/forums/viewtopic.php?f=3&t=492

[gastric]

Thank you for the additional assistance. Seriously, you're tireless with your help. Rock on!

There very few reasons for not being able to program Atmega using an ISP cable:

1. The ISP cable is not wired correctly.

I've followed this diagram:



However, I apparently am unable to comprehend how the image of the DB25 corresponds to the actual pinouts. Score one for being too stupid the first dozen times I looked and reviewed the cable, but later score one for being just smart enough to Google DB25 pinouts, see this image so I could fully realize my issue:



and realize I wired it ass backwards.

Re-wired the ISP cable, PonyProg STILL failed the IO probe. However, it could successfully read and write fuzes and successfully write and verify bootloader, and VIOLA! my LCD is now prompting me for a FW Updater 16Mhz. HOORAH!

The only thing that differed in my fuzes were that SPIEN was checked, but dithered (as in your image) so I could not uncheck it.

[gastric]

I'm the happiest boy in the world!

Well, that was quite an adventure. Everything appears to be working again. I've uploaded firmware and am about to reinstall the board into the chassis and re-rack it. In conclusion my issue appears to have been:

1. Lost bootloader during fimrware update. Possibly related to MIDI loop in MIDI-OX routing. I'd be happy to do some testing in regards to that if Dmitry is so inclined, now that I'm confident I can correct the issue.
2. Wired my ISP cable in reverse by not comprehending the cable diagram correctly. Total user error, which very well could have been the cause of my V2.5 failure as well, though DMM testing of that board indicated other issues. I'll revisit it some day to see if I can resurrect the V2.5 board.

Hopefully my pain and suffering and frustration can benefit someone else.

Enjoy.

[dmitri]

1. Lost bootloader during fimrware update. Possibly related to MIDI loop in MIDI-OX routing. I'd be happy to do some testing in regards to that if Dmitry is so inclined, now that I'm confident I can correct the issue.

It could have only happened if fuses were not programmed correctly.

[gastric]

I briefly tried to reproduce the MIDI loop while programming the firmware and couldn't cause a failure. So I'll chalk it up to a missing fuse or some other odd scenario.

[jman 31]

I'm the happiest boy in the world!

Well, that was quite an adventure. Everything appears to be working again. I've uploaded firmware and am about to reinstall the board into the chassis and re-rack it. In conclusion my issue appears to have been:

1. Lost bootloader during fimrware update. Possibly related to MIDI loop in MIDI-OX routing. I'd be happy to do some testing in regards to that if Dmitry is so inclined, now that I'm confident I can correct the issue.
2. Wired my ISP cable in reverse by not comprehending the cable diagram correctly. Total user error, which very well could have been the cause of my V2.5 failure as well, though DMM testing of that board indicated other issues. I'll revisit it some day to see if I can resurrect the V2.5 board.

Hopefully my pain and suffering and frustration can benefit someone else.

Enjoy.

Good job man, glad you got it. That's one thing for certain about diy.... You can look at it 50 times and still see it wrong!

[gastric]

I physically constructed the cable last year during my V2.5 build. So re-reviewing the diagram I assumed I was viewing the connector correctly and that it was pinned for the actual male connector side, not the solder lug side. Very goofy mistake. I noticed it when posting a reply with Dmitri's ISP diagram, a photo of my cable, and my text description in my reply.... then it hit me that the pin #'s could be for the solder lug side which would make a lot more sense than showing it for the physical connector side and the light bulb finally went on in my head. Haha.

Once I'm done screwing with my triggers and various MD parameters and everythings working to my satisfaction I'll revisit the V2.5 board to see if I can resurrect it.