Not exactly robot related, but here's my situation:
I've got an unknown IC with an array of 8 input pins (suspect its an IDS1100 or 1200 series, pins A0-A7). Two of them have built in pull-up resistors, the rest have built in pull-down resistors. The problem is that this is not the DIP form, its the die form. I can get to the pins (barely), but I don't know which pins are which. I just need to separate those that are high from those that are low.
Looking at the schematic on the datasheet, I'm thinking that I can test this with a continuity test to either the Vcc or GND rails without powering on the chip. Is this true?
If I need to power the chip to test it, what's the safest way to test? I don't want to inadvertently smoke the chip. Are these the results I should be looking for?
Voltmeter readings, testing from the pin in question to:
Test to GND, get 0v, this is a Low pin
Test to GND, get Vcc, this is a High pin
Test to Vcc, get 0v, this is a High pin
Test to Vcc, get Vcc, this is Low pin
This is probably pretty basic, but I'm still green at this and I only have one of these chips and I can't replace it.
Thanks for your insight.