Call for help, please on Synthex kit.

[gabriel1712]

Gabriel1712,

Did you get yours running and stable?

You did help me.. see above post.
Hope you are having luck with your machine..

Regards, B.

Yep, mine is running with no problem. It's only when I need a firmware update and hurry throu the step-by-step, forgetting stuff that I get into trouble.

I too vagely recall someone explaining the button push as interrupting a current = if the keys aren't there, you're infact constantly pushing the buttons. Give it a go.

[ilporcupine]

Hi again, all.

I just got back on after a few days, and saw most recent post.

Gotta disagree, the buttons are "normally open". Not connected to anything until pressed.
Both times I actually had this thing up & running, buttons were not connected.

Problem now is USB not connecting, so I cannot even try to update again.

B.

[ilporcupine]

He's BAAACK!

Update/Summary:

Could not get Windows to recognize MD USB Midi any longer, so I reprogrammed PIC 18F2550 with synthex version of firmware. 12Mhz v2.hex
(Used PICKIT2 programmer, couldn't get consistent result with ICSP cable, nice gadget, HV or LV prog.$35US)
Windows now recognizes, and installs MD USB MIDI.

MD still coming up in "FW Updater" so next step, reinstall MD firmware. MIDI OX giving message that it cannot open Output port "MD USB MIDI" "not enough memory".(!!?) Sometimes it seemed to try to send sysex, and then hang, requiring task manager to close, and reboot. Reinstalled MIDIOX several times, with same result.

Finally, I decided to go back to basics, built the prgramming cable, set up PonyProg, and installed bootloader again. Still no luck getting sysex to transfer to MD(midiox problems) SO.. I programmed the atmega with the .hex version of firmware (32_16_32 20090517.hex), bypassing the bootloader. NOW MD consistantly comes up in the Copyright screen on powerup, and windoze consistantly recognizes it, and MEGADRUM USB MIDI shows up in dialogs of all programs as an option for MIDI in/out, YEEAAY!

Next, reinstalled & setup MCT, and tried out with MD.. Looking at Application Log I CAN see the midi output of MD,
this GOOD!
Tried to save/retrieve settings to & from MD, but MCT either appears to do nothing, or hangs, requiring taskmanager close of all java to close. Looking at the Application Log, seems to be opening the INPUT port, but NOT the OUTPUT port of MD USB MIDI. Several times when opening, got initialization error box, and reselected MIDI devices. Appears to accept, but bidirectional comm. is not working..cannot save to/read from MD.

This all seems to point to problem with the USB MIDI, but why Input works, but not Output, is confounding me...
at least I have the firmware working again...

Synthex and Dmetri, care to weigh in? I DO know how to read a meter, solder, etc., and I think Ive provided detailed info on setup, and my steps to rectify..

Thanks, again
B

B.

[dmitri]

Look at http://www.megadrum.info/forums/viewtopic.php?f=3&t=268
Use my version of USB firmware, pull pin 26 of PIC18F2550 to the ground over a resistor and USB problems will go away for good.

If you're unable to load firmware using MIDI-OX, then either you didn't follow http://www.megadrum.info/forums/viewtopic.php?f=3&t=622 to the letter or your computer configuration is screwed up.
Check the board for breaks/shorts and especially loose connections.
Try another USB port.
Try another PC.

The thing is that as long as you have problems loading firmware using the bootloader, you'll have problems with MegaDrum even if you write MegaDrum firmware directly using PonyProg.

[ilporcupine]

Thanks, Dmitri, for the input.

I have seen the topic about the pulldown resistor. Can you shed some light on what the issue is with the PIC's?
I read it again, and I thought it was only on random pieces? I couldn't figure how to "mechanically" attach a resistor in there, and others were using the original design without problem. If I have a bad PIC, I can replace it and reprogram, (I have extras!).

As far as my board goes, if you can shed any light on where I could look for a break/short that would cause the behavior I described, I will go thru another hundred times looking for it.
I have had all IC's off & on this thing (for resistance measurements) so many times, Im wearing out the pins!

I tried on the old machine that I used to program with (!Ghz pentiumIII, Win 98se) (Yeah,, I know, but runs my old cakewalk stuff like bat outta hell) and win98 is NOT usb MIDI friendly. Only XP machine around is GF's and I would not dare!


Thanks, B.

[ilporcupine]

Here is a sreenshot of config on PC, looks fine to me, look OK to you?

USB.PNG

Drivers.PNG

[dmitri]

Thanks, Dmitri, for the input.

I have seen the topic about the pulldown resistor. Can you shed some light on what the issue is with the PIC's?
I read it again, and I thought it was only on random pieces? I couldn't figure how to "mechanically" attach a resistor in there, and others were using the original design without problem. If I have a bad PIC, I can replace it and reprogram, (I have extras!).

To make the story short, just use my PIC18F2550 firmware and solder a 22k-47k resistor between pin 26 of PIC18F2550 and the ground as it is recommended by Microchip. I don't know why, but Synthex's PIC18F2550 firmware doesn't work in this case. While USB connection is unstable all sorts of things can happen.

[ilporcupine]

Well now...
I reprogrammed the PIC back to Dmitri's firmware, and used a 4-pin connector (from kit) to temporarily attach some series resistors(no high value ones on hand) between pin #3 and #6 on the ICSP connector. (Functionally same as pin26 on PIC & ground)

This appears to have fixed the USB problems, and by extension, will allow me to reinstall the bootloader, and update firmware via USB MIDI. It's 3:30 am here now, so that will have to wait until tomorrow.

Assuming that was indeed the problem, MY DIY skills are no longer suspect, as my board will have been fixed without fixing a single cold joint, shorted trace, loose connection, bad cable, polarity reversal on components, or
failure to follow instructions for programming, or anything else..

Did a bit of snooping on PIC forums, seems this resistor keeps RB5/PGM pulled low during normal operation, and without it, PIC can enter LVP mode, guess that IS a problem..I would have added it long ago, if I'd known it was Microchip recommendation on all 18F2550. I thought after reading the topic initially, that it was only a few samples of this chip.

Nice to know.

Thank you, Gabriel1712, gastric, and Dmitri, for your assistance, I may have a working unit, yet!!

Brian

[ilporcupine]

JEEZ, I gotta go to bed, looking at "who's online", it's just me & the Google bot !

[ilporcupine]

I now am the owner of an (apparently) FULLY FUNCTIONAL Megadrum Board!!

Bootloader reinstalled, and flashed with the latest firmware. (Using MIDI-OX, without a hitch!)

Now I can get back to working on the case, jacks, button board, etc. with an easy mind!

Thanks again to all who helped out.

Brian