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Old 20th Feb 2021, 12:27 pm   #9
ortek_service
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Join Date: May 2018
Location: Northampton, Northamptonshire, UK.
Posts: 1,394
Default Re: Reading PROMs with a Raspberry Pi

I suppose you could always switch the power to the EPROM, and also put tristate buffers on the address / data & chip-enables, to prevent possible latch-up when power is connected
Or (if port lines go direct), insert some series resistors of a few kohms / set them to inputs in the software and only set to outputs when actively-reading the device.
Although starting to run out of GPIO lines to do this on software control, and hardware is getting a bit more involved and might be tempting to go the whole hog and use proper pin-driver circuitry on each line with ability to do an insertion test to check for bad pin-contacts which can be useful to ensure valid readout when copying devices.
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