Maker Pro
Maker Pro

simple EPROM test circuit


Steve Lewinsky

Jan 1, 1970
Im looking for a very simple circuit that will allow me to piggyback a 27XX
series EPROM with a test clip of some sort. Then as I power up my main board
if any of the address line go high on the eprom it will latch a transistor
or something and hold a LED on until I remove power. This way I can see it
the address lines are in fact getting turned on.

Geoff Hackett

Jan 1, 1970
You can buy IC test clips that straddle the device and connect all the pins.
A octal latch is best to capture the bus data. 74ls373 or 74ls573 this can
drive the LED's though a driver or transistors. You may want to decode a
certain address as well.


Jan 1, 1970
you really can not trust what you are looking at When you do this AT
powerup there will be a lot of garbage on the lines. What you really need is
a snapshot of the lines right after POWER ON RESET.