GM5 Error

Testing/Troubleshooting
1

Hello,

I’m trying to get my GM5 modules up and working, but something weird is happening… I want to build 2 GM5’s (1 x 10 Inputs, 1 x 10 Outputs) I have ordered the small PCBs so I have to build the breakout board.

I soldered the small PCB and destroyed J1 and J2 as said in the GM5 PDF file. In this PCB there’s no J8 jet so nothing I can do there.

What happens when I connect this module to several PCs, I only see one input port instead of 10 and I don’t know where to look honestly (I used MIDIOX for checking)…

Anybody who can help?

Thanks!

Hans

2

By destroying J1 and J2 you will get “110” as resulting configuration -> “I only”.

This matches with your observations.

For your usecase, there was no need to remove the bridges - “000” was fine for 5 inputs and 5 outputs, and with two modules you would get 10 inputs and 10 outputs - like intended?

Best Regards, Thorsten.

3

Thanks for the reply TK,

The purpose of this 10 In and 10 Out setup is that I’m building (for my thesis at school) a big console for “sample controlling”. This table will control ardour because this software is completely open source. So I need one computer with Linux (with 10 MIDI outputs) and another running Windows for the use of VST instruments (10 Midi Inputs) because VST is not good supported by Linux.

So that’s why I wanted this 10 In and 10 Out divided. But as I read, the configuration I took gives me only one Input? Is there some way I can change the configuration and create 10 Inputs for one module and 10 Outs for another? I was thinking of Using the EEPROM for this setup.

Sorry for being a “difficult customer” (like we say in belgium)

Thanks!

Hans

4

You just need to change the config jumpers like TK said. Look at this again, especially the config table: http://ucapps.de/mbhp/mbhp_usb_gm5.pdf

You have them set to “110” - “I only”

You need to set them to “000” - “5 IO” per board.

“0” being a connection and “1” being no connection. Which means you need to fix the two traces you’ve broken.

5

Also, the information given will give each module 5 inputs and 5 outputs.

If you need 10 inputs separate from 10 outputs, you’ll need 2 modules on each side.

Have Fun,

LyleHaze

6

Thanks for the replies,

I indeed need only Outputs on one computer (Linux system running ardour for tests) and Inputs on the other computer (win XP system, running VSTs). The GM5 looks like a perfect option because it’s very difficult to connect these 2 OS’s with MIDI. The GM5 works fine on both, that’s why he’s so interesting for me.

Is it possible to adapt the EEPROM in such a way that I can make an input out of every output? (I know I need some hardware adaptations as well in this case, but this is OK) I just did some testing but It seems not possible…  Any suggestions, or is it always max 5 Inputs/GM5.

Thanks for all the help again!

Hans

7

Changing inputs to outputs would (if possible at all) involwe hacking the firmware of the gm5, since it is not open source…so it’s nearly impossible.

But did you realize that every midiport has 16 channels, wich could control a VST each?

I doubt you really need 10 midi-connections in parallel…

8

No, the firmware can “only” handle up to 5 inputs and up to 5 outputs (it’s already magic for such a small Atmel device!)

You will need 4 x GM5 for your usecase

Best Regards, Thorsten.

9

Changing inputs to outputs would (if possible at all) involwe hacking the firmware of the gm5, since it is not open source…so it’s nearly impossible.

Even hacking won’t help here - Ploytec already pushed the chip to the limits :wink:

Best Regards, Thorsten.

10

That’s what I needed to know, I order some more chips soon.

Thanks!

H

11

Btw.: I’m going to arrange a special deal with Ploytec, so that it could be possible to get new GM5 chips soon, although we haven’t reached the 250 pieces mark yet

Best Regards, Thorsten.