Re: apple II roms and eproms

["Bill Garber" <willy46pa@comcast DOT net>]

"Bill Garber" <willy46pa@comcast DOT net> wrote in message
SvadnZVbwNX1D0ndRVn_iw@comcast.com">news:SvadnZVbwNX1D0ndRVn_iw@comcast.com...
:
: "Igor" <ikanja@despam....com> wrote in message
: xn0djpsie59fgi000@powernews.libero.it">news:xn0djpsie59fgi000@powernews.libero.it...
: : Reading past messages I've understood that AppleII+ roms are
: not pin
: : compatible with eprom chips. Is that true also for Apple
: IIe/IIc/IIgs
: : roms?
: : If not, what kind of eproms should I use to back up or
: substitute them?
:
: I know that IIe in the US are 2764 for CD and EF,
: 2716 for Video ROM and KeyBoard ROM, but the Euro
: models are 2732 for Video ROM as they are dual-
: language. The Platinum //e has CF rom which would
: be 27128.
:
: The ROM-FF or original IIc ROM is 27128, and ROM00
: through ROM04 take 27256. I assume that Video and
: Keyboard ROMs follow the IIe US standard since they
: weren't marketed in other countries.
:
: The IIgs I am not sure about, I've heard they are
: eprom compatible from one source and not compatible
: from other sources, so I won't claim either now.

Some II/II+ info to help with the adapter.

The II/II+ ROMs have 3 chip selects:

18 = CS2
20 = /CS1
21 = /CS3

The 2716 has the following:

18 = /CE
20 = /OE
21 = Vpp (+5v for READ, +25v for program)

Jim Sather shows a design for an adapter:

Apple II -> 2716
18 -> 21
20 -> 20+18
21 -> n/c

I have an outline somewhere and also I began
a schematic for making these. You'll mostly
just want to mod the F8 rom, I think.

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - willy46pa @ comcast DOT net
Change DOT to a dot to contact me



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