Difference 23512 and 27512 Eprom

[birs23 at zeelandnet.nl]

You can find that here : 
http://www.xs4all.nl/~ganswijk/chipdir/holtek/ht23c256.txt

For a 27256 you can look here :
http://www.xs4all.nl/~ganswijk/chipdir/giicm/27512.txt

Cheers,

Stefan

At 23:09 22-10-2004, you wrote:
>Hi
>  I guess the next thing is to find a pinout for
>the 23512 to see if they have a select that is inverted
>that might need to be patched around to read on
>a standard programmer.
>Dwight
>
> >From: birs23 at zeelandnet.nl
> >
> >Dwight, not missing the discussion ;-)
> >
> >At 19:15 22-10-2004, you wrote:
> >
> >> >From: ard at p850ug1.demon.co.uk
> >> >
> >> >>
> >> >> Hi,
> >> >>
> >> >> I know very little about electronics and eproms so this question 
> might be
> >> >> really easy. I would like to know what the difference is between a 
> 23512
> >> >> eprom and a 27512 and if there are any differences if its possible to
> >> make
> >> >
> >> >I thought the 23512 was the mask-programmed part (not an EPROM), and is
> >> >otherwise the same device. You should be able to read it (unless your
> >> >programmer tries to be clever and read the manufacturer's ID word, etc).
> >> >
> >> >-tony
> >> >
> >>
> >>Hi Tony
> >>  I think you are right about the 23xxx being mask versions.
> >>The problem with the newer EPROM parts is that they do not
> >>require pulsing of the programming voltage. Many programmers
> >>simply leave the programming voltage high while reading or
> >>verifying. This is real bad for mask parts. Also, most mask
> >>parts use the programming voltage pin as another select.
> >>This means that it may need to be in the opposite state that,
> >>even a programmer that allows setting of the program voltage,
> >>may not be in the right state to read.
> >>  Also, I think this fellow is off the list and doesn't realize
> >>that he is talking to a list. I suspect he is missing our
> >>conversations related to his issue.
> >>Dwight
> >
> >