elongating the ICD cable.

treitmey · Joined: 23 Jan 2004 Posts: 1094 Location: Appleton,WI USA

Has anyone come up with a trick where I can elongate the ICD-U40 cable.

For a while now I have been using a 2.5foot ribbon cable.(nice and flexible)

but now all of a sudden its started failing. I shortened it up to 8" and now all is well. I just wonder if a resistor in the right place would allow me the longer
cable again.

Come to think of it.. While it WAS working the ICD was also used by the keypad port with 10k pull-ups. I have to look into this...

Konrad · Joined: 15 Sep 2003 Posts: 34

I have just started messing with a dsPIC. On the Microchip forum people recommend adding 100pF caps to the prog and data lines to stop crosstalk. They even meantion problems with some 18F parts. Myself I have never had a problem, but it may help with longer cables. The caps need to be at the target end.

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

Too much capacitance will also cause you problems as well as resistance. It will affect the rise and fall times of the data signals.