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Altera_Forum
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14 years ago

Output Pin Driving Another Output Pin

Hello all, I've run into an unusual problem. I'll start off by describing my goal: I'm designing a circuit that can test for short circuits and open circuits in a wiring harness. The wiring har...
Altera_Forum's avatar
Altera_Forum
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14 years ago

Indeed the recommended solution would be using buffers. These will also help to protect CPLD pins from damage which is likely in case of such long wires possibly, shortcircuited and maybe subject to esd or other kind of electrical surges.

I'd use a transistor array, pull up resistors <=10k and I'd design the test cycle in order to minimize errors due to electrical coupling or emi (i.e. for the 3rd wire, test both with 00100000 and with 11011111 pattern)