Just checking my failing memory.
I have a 20 cm long flat ribbon cable that connects two circuit boards I have designed (the distance is for convenience as both boards are used for prototyping purposes - the final circuit will be on a single - but more complex - board). The signals are all in the 0-3.3V range and switching at up to 5MHz (there are power and ground lines as well).
When the cable is not connected I'm getting clean signals at the controller board, but when the cable is connected (with or without the other board) I'm getting huge amounts of spurious transitions and (what looks like) crosstalk.
I realise (now!) that I should be terminating the data lines but I'm just checking with the experts to see exactly what that termination should be. Is something like a 470Ω resistor to ground the thing to use or is it better to use a 100nF capacitor to ground? Or both?
Thanks
Susan