fallenturtle

Midibox SID: Simple Control Surface and LCD wiring questions

4 posts in this topic

Things are going well with my Midibox SID construction... I've finished the CORE board and I'm loading up the SID board, but I've gotten to the point where I"m looking more into how I'm going to wire up things. I have questions and google and search on this forum aren't helping me find answers (not that they aren't there, but I'm having trouble finding them). Anyway, here it goes:

LCD Wiring: While both the CORE4d and my LCD use a 16(2x8) pin connector the pin mapping is completely different. I'm wondering what's the best/easiest method for rerouting the wires in the ribbon cable... My thought was either simply cut the cable in half, separate the individual wires, connect the correct wires to each other, solder, and heat shrink them. While the colors repeat twice, the ribbon wires are color coded, so that will help make that less a headache I think. The alternative I though of was to use additional connectors and headers on a piece of stripboard and do the remapping on the board, essentially creating a little conversion board.

Buttons Connections: I haven't found a wiring diagram to explain which buttons connect to which pins on the SmashTV DIN board but I did find the assignments in the software code, so I figured I'll create a chart for others in the future who have this question. I do wonder if there is a best practice or something for how to wire up all the ground pins. Do I chain them in someway?

MIDI Connector wires: For the 3 wires needed for each of these I thought I might butcher an old floppy drive ribbon cable into 3 wire strips. The gauge of this wire is pretty small, will that be an issue with the MIDI signal?

Audio Connector wires: Do I need a specific gauge and/or shielded cable for these connections?

 

Thanks!

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LCD wiring: I've done both option that you mention (cut, resolder, shrink tube, or adaptor), both work. None of them have failed me over the years, but I kind of think the adaptor board is more transparent when troubleshooting. I've found that soldered ribbon cable connection can break if there's too much movement. Well that's like any soldered connection, but because the gauge is so small it's more vulnerable. With an adapter board + wires you can see if a wire has broken off, but with the connections inside shrink tube you have to use a multimeter to beep every wire.

I would probably make an adaptor from a simple strip board if I have the space for it (solder on a 2x8 pin header, cut the strips in between the header length-wise and then reconnect with air wires). The last time I did it I didn't have the space, so I did the cut-resolder-shrinktube. In the end it is probably not that significant though.

Buttons: When I did my own control surface years ago, I chained the grounds of the buttons/encoders/LEDs that were near each other. In principle you could take just one GND from a DIN or DOUT board and then just chain everything from that point. Primarily it's a matter of your control surface design I guess. This applies to the "best way" of wiring the buttons as well. If you found the designations in the code, you can probably change them to your liking pretty easily. Just keep in mind that encoders are always assigned to two pins so that the pin designation (designating the first pin of the pair) is always 0, 2, 4, or 6. Designation "0" takes pins 0 and 1, "2" takes 2 and 3 etc. "3" doesn't assign pins 3 and 4, it just won't work.

MIDI IN needs only two wires (pins 4 and 5). I don't think ribbon cable gauge will have a negative effect on the MIDI signal.

Audio: I've used 0,25qmm wire or smaller gauge (no shield), I've never had any problems that I can hear.

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For the SID with PIC 18F4685 the LCD have to run in 4-bit mode.

Use this diagram http://www.ucapps.de/mbhp/mbhp_lcd_4bit_mios8.pdf

For the buttons and encoder, use this http://www.ucapps.de/midibox_sid_cs/mbsid_v2_din_default.pdf

Ribbon cable is fine for MIDI

For Audio, it depends on how far away from the SID module you are stretching the wires, and what other wires or circuits the wire pass on the way. For best results, use a shielded audio wire.

Good luck :) I have built 3 MBSID's

Pics would be nice

  

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