Can I use a 27C040 eprom instead of 27C020?

Haven't done this since the 2764 days, but you need to make sure you don't have any floating address lines. If there's an extra address pin, you can tie it high, low or to the next lowest address pin, depending on which is easier in your circuit. Program it in the same configuration. mike

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Remember to duplicate the data over the two halves of the chip,

Why? mike

On Sat, 26 Mar 2005 05:37:21 -0800, mike put finger to keyboard and composed:

Because then it won't matter whether the extra address pin is hardwired high or low in your circuit. The OP's job may be a repair of an existing design, not necessarily a new design of his own.

- Franc Zabkar

one.

I'm not familiar with that part, but with the 2764 we would burn the data into the lower half and ground the pin for the most significant bit so all that was accessible was the lower half. This assumes that the pinouts for both chips are substantially the same.

covers your butt incase you activate the extra address line. no change that way.

Thanks for the help. I'll be able to erase the old eprom's now as I now have access an eprom eraser. :)