simple EPROM test circuit

[Steve Lewinsky]

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]

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.


"Steve Lewinsky" <lewinsky0857@NO_DAMN_SPAMrogers.com> wrote in message
news:5FQtb.88922$Rah1.11951@twister01.bloor.is.net.cable.rogers.com...

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.

 

[Jimmy]

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.


"Steve Lewinsky" <lewinsky0857@NO_DAMN_SPAMrogers.com> wrote in message
news:5FQtb.88922$Rah1.11951@twister01.bloor.is.net.cable.rogers.com...

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.