SPI devices in parallel.

[HenrikOlsson]

Nah, I don't think those are suitable, they look more like differential analog drivers - not really what you want.

I was thinking more on line of a DS9638 on the master and a DS9637 (or similar devices) on each of the slaves:


/Henrik.

[AvionicsMaster1]

Terribly sorry. I assumed most digital pots CS line requirements would be the same. The question wasn't about power supply it was about control and I again assumed that any pot chip would work about the same. Obviously bad assumptions on my part though I assumed a worst case scenario and replied on that.

I stated I wasn't an engineer and had no experience but I assumed a shield on the CS line and if necessary the power supply lines. He could also use a twisted pair on the power supply which should reduce noise collection.

I again assumed that a small conductor cable wouldn't create a great capacitor and with the slowish switching speed I assumed that wouldn't be a problem.

So now I've been straightened out and I apologize for leading anyone astray. Please let us know how you proceed and more importantly, your solution.

[jmgelba]

Dont worry about it.

I'm going to try the drivers and will be using standard cat5 cable and connectors. Makes things really easy.

[jmgelba]

Just a thought, connect a 1K resistor to the output of each receiver and connect the other end of the resistor to the base of a 3904 transistor, I think I should be able to turn on an LED each time the line goes high without loading it. It would be really nice to have a simple led showing activity on the data lines at each light, as a cable and connector diagnostic.