Any Recommendations for Interboard Cabling

AccordionProp

I need some help regarding cabling for a Propeller project.

I'm gradually building a MIDI Piano Accordion as real ones are far too expensive.
(I'm also interested in using the Propeller for sound synthesis if things work out, but may need Propeller 2 for this when it appears.)

I'm using the standard Propeller protoboard as the central processor with satellite circuits polling the treble and bass keyboards, using HC4017 and HC165 chips.
This requires 8 lines (including power and ground) and a cable run of 12-18 inches to each satellite circuit. What sort of cabling should I be using?
Should I be using simple shielded multi-core cable, or individually screened cores, ribbon cable, twisted pair or something else. Does it matter at this sort of distance?
Are there any EMI implications?

Any advice much appreciated.

Leon

With those lengths of wire it shouldn't matter. I'd just use a ground and signal pair for each connection, twisted together.

Leon

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Mike Green

Probably the easiest thing to use is simple ribbon cable. If you've got 6 data lines plus ground and power, add a ground line for each data line and use 2 or more power lines all interspersed with grounds. That would be 16 lines which is a nice match for a 16 wire ribbon cable with a dip plug on each end. You could also use a 16, 18, or 20 pin female header on each end with a corresponding cable. Add extra ground and power leads for the otherwise unused leads or leave some of them for future expansion.

AccordionProp

Thanks, that sounds most encouraging.

Timothy D. Swieter

I second the ribbon cable. Easy to work with. IDC (insulation displacement connectors) are inexpensive, but get extra because you may break one or two when attaching them to the ribbon cable if you don't use the proper tool. I have used ribbon cables in my LED displays and have had minimal problems. When I do another design, I would use ribbon cable again, but I would follow Mike's advance regarding adding grounds and more power lines.

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Timothy D. Swieter

www.brilldea.com·- uOLED-IOC, RGB LEDs, TLC5940 driver PCB
www.tdswieter.com

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One little spark of imagination is all it takes for an idea to explode

Beau Schwabe

AccordionProp,

Ribbon cable with interdigitated grounds should be fine for that distance.· Also be sure to have decoupling caps (at least .01uF) across the VSS and VDD of the HC4017 and HC165 IC's.

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

AccordionProp

Have put in decoupling caps.

I have 2 complicating factors. The first is that I'm hoping to drive 6x HC165 chips spread over 4 separate satellite cards using the same control lines (LOAD/SHIFT & CLOCK) from the Propeller (1 for treble keyboard, 1 for bass keyboard, 2 for dual joysticks and 2 for two banks of couplers(voice switches). The second is that I'm using a matrix of small neodymium magnets with reed switches and 1N4148 signal diodes to detect the key depressions, so I may have to run the satellite circuits at 5V, rather than 3.3V. I'm setting up a plugboard to test this out.

Brian218

I concur with ribbon cable. Here are a couple of methods <No pun intended!> that I've used to connect a Propeller and SX48 protoboard to my breadboards.

For the SX protoboard, I used ribbon cable soldered to the board with 16 DIP connectors that plug directly to the breadboard. It works reasonably well, although some type of SIP connector plugged into the breadboard would allow a bit mor room.

On the propeller board I used 4, 8 pin SIP connectors, which works very well. One word of caution about using this type of connectors with breadboards. Some connectors will not plug into the breadboard securely, so try plugging the connector into the breadboard before soldering.