OK, so I get my shiny new AT28C256 in Friday. I had been using the 8K version previously.

So after everyone was in bed, I thought I would try it out on the SBC I'm building.

Well, the first thing I noticed was that the pinouts were ALL wrong. I mean, I thought it was going to basically be a drop-in replacement. Nope. I mean every pin seemed different.

So I re-wire everything and nothing. Nothing works. I take it out and program it just fine. I verified the ROM image wrote successfully.

After 2-3 hours of checking and re-checking the datasheet, I gave up and went to bed.

The next morning I discovered my error. I had been looking at the TSSOP pinout instead of the PDIP!!! Boy am I dumb! LOL

Ugh....lesson learned. Read the GIANT header before you start making assumptions. LOL

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Cat; the other white meat.

lol it happens to us all. I do things like this when I'm knackered and (unwisely) decide to work on a project instead of going to bed. At least you didn't blow anything up re bus contention, etc (I hope!).

Happens to all of us at least once. Sounds as though you got lucky and didn't smog up the place when you turned on the juice.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Yeah, I was really surprised that I haven't fried the chip. I was even running at 5v and saw 70+ mA!

But, I've taken it out and loaded the contents with rom-burner and it shows the contents are still there and I'm able to reprogram it.

Good thing I bought two of them just in case.

lol

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Cat; the other white meat.

My last oops (back in 2013) was laying out an I/O board (PCB). I had the reverse gender DB-9 and DB-25 connectors for the 9-pin serial and 25-pin parallel ports (but installed the proper gender connectors on the board). The kicker was the transmit pin remained the same so I was getting garbage kicked out from the port, which made debugging, ah, more interesting. It just happens!

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Regards, KM
https://github.com/floobydust