On Tue, May 19, 2015 at 6:20 PM, Richard B. Main, Esq. <mainpate...@gmail.com> wrote: > That just sounds wrong to me applying +25v to do a read/verify. You're > misinterpreting the datasheets. Richard
It may "sound wrong", but that's actually the *only* way to read the EPROM 8741, 8741A, 8748, and 8749. If you don't apply high voltage to the EA pin, it doesn't go into verify mode. It's fully documented in the data sheet, and I've verified that commercial programmers do that. It's possible that verification will work at somewhat less than 25V, but it definitely does NOT work at under 6V. The issue is that the 8041, 8041A, 8048, and 8049 masked-ROM parts are not rated for 25V on EA. The 8748 and 8749 datasheets say to use 12V on EA. The 8041 and 8041A datasheets don't say, but since it's almost the same design and definitely the same fab process as the 8048, I'm pretty sure that they need 12V also.
