I searched on this but could find nothing specifically about my questions. It seems the search engine is not that specific and if I put IIe in the search, everything with IIe in it comes up. It appears to be doing an 'or' on keywords rather than an 'and'.
I've got a couple of questions to those that might have done a DIY enhancement. (one using EPROMs rather than ROMs)
1) Do I loose anything by doing this? i.e, Will there be any significant incompatibilities caused by the enhancement? (not specific to using EPROMs)
2) Will the IIe motherboard accept 2764 and 2732 EPROMs without modification?
There is always the possibility of an application trying to use an Undocumented Entry Point in the ROM, so if you change it, something might break..
Reactive Micro sells Apple ][e Enhancement Kits, with Regular EEPROMs..
The BASIC and Monitor ROMs appear to be 2764's...
MarkO
When the enhanced IIe came out a lot of people saved a few dollars by buying a 65C02 and burning their own EPROMs.
As I recall there weren't many applications or games that didn't work on the enhanced IIe. On the other hand there were quite a few that required an enhanced IIe.
There was one story circulating back then about a couple of guys that wrote a game. Before they wrote the game they found that their 6502 had a couple of undocumented instructions which they used extensively. As soon as they started selling the game they got complaints that it didn't work. That's when they found out that Apple used more than one brand of 6502.
Hello BillO,
as summary you might take this:
the amount of games not compatible with IIe enhancemnt can be counted with ten fingers....
the amount of software supporting the features of the enhanced will count to the hundreds....
just to mention the support of all games using the enhanced Double Hires screens and the
software using the additional mouse features like mousepaint, mousewrite and numerous others packages...
If you carry out the enhancement be sure to use the correct set for your computer and your needs
( this is a reminder to keep within one language and county set )... see this table:
http://www.appleii-box.de/H000_Chipsets.htm
In fact besides the use of the additional features counted up till this point the other point not mentioned yet
is the set of additional instructions of the 65C02 and also saving a small amount of power....
the rest is up to your own favors and choice...
anyhow most users in the past days did perform that update.....
and of course if using Eprom you should use the correct ones...
sincerely speedyG
Thanks for sharing your experience guy's. As usual, it is much appreciated.
When it comes to the base core hardware, I prefer keeping things original. Or if upgrading something, upgrading it according to manufacturers specifications. This includes using OEM parts or their approved equivalents.
I consider the Enhancement Kit an official item.
If using EEPROMS, the same size and array layout should be used.
The 2764s and the 2732 are the right size, but they do have a few pins with different possibilities than the ROM versions, hence my question. It is possible that Apple could have made this difficult, if not impossible. In fact, there are some incompatible differences with the pin-outs of the 6502 and the 65C02. Being the sort of person I am, I still need to check them out. It is quite possible to do damage to a 65C02 placed in a socket that is just fine for a 6502. I just need an Apple IIe schematic to put my mind at rest, or break out the scope and DMM.
I know history should put my mind at rest, but I'm an odd combination of type 'A' and AR. In all honesty, I feel the latter part of that combination has held me back somewhat, but it's part of me.
Maybe you’re being a little overly cautious. The manufacturer thought they were compatible and produced millions of them that people used for 30 years.
There is no issue if a set of 2764 and 2732 Eproms are used and the 65C02 is inserted.
The set works well and even Apple themselve distributed for a fair well period the set
in Europe with labeled Eproms......
in the period from 1983 to 1986 the Apple User Gruop Europe had nearly 480 members in
Munich area and this upgrade had been performed about 250 times.... during this period
i have been the technical advisor in our user group responsible for testing and repair....
i have´nt seen a single issue with that upgrade..... ( including my own 2 Apple IIe´s )
and i remember very well the period afterwards, when new software arrived that supported
the features and several guys in our group writing bunches of software using the features...
speedyG
Thanks all. Was not aware that Apple published this upgrade on EPROMs. I'll give it a shot today. Now, where did I put that programmer?
Well, I burned the EPROMS and they seem to work just fine, but out of 2 WDC 65C02s both seem to be bad. With them in the board it behaves just as though there were no processor at all (Yep, I tried that).
Is there something I'm missing? Perhaps there is a problem with WDC 65C02s or a jumper I did not set? It seems weird that both would be bad.
Hey, success!!!
Well, after doing a bit of digging during spare minutes I found out that there are some important differences between the R65C02 and the W65C02. Then I came across this document: http://www.westerndesigncenter.com/wdc/AN-002_W65C02S_Replacements.cfm
So, not wanting to modify my Apple IIe MB, I modified the W65C02 like this:
1) Cut off pin 1.
2) Bent pin 36 up and back
3) Connected pin 36 to pin 8 by soldering in a fine wire
I popped it in my Apple IIe and now I have an Apple //e!
The EPROMs I used were:
For CD/EF - AMD 27C64
For Char - ST M2732
Hello BillO,
well this is just confirmation that old dogs still might learn some new stuff....
in the "old days" there have been only the 65C02´s from Rockwell and Signetics availiable....
WDC kicked of their CPU´s far later ( what i found out after some research and after reading the pre-previous posting )
so there is really a difference between that WDC devisces and the earlier released CPU´s .....
thank´s for that info´s - i added that updating info into my archive....
sincerely speedyG
When I purchased my enhancement kit back in the old days of the 80's, it came with a WDC65C02P-2.
@Bill0, the devil is in the details. The "S" suffix in your chip makes all the difference in the world. "S" means it has a static core. A feature that allows the primary clock to be stopped, hi or lo, without data loss. Great for radiation reduction and power saving applications. The Apple //e doesn't support this static core - hence the modification.
Unfortunately, they do not make the older dynamic core chip anymore. Only the W65C02S.
According the A-IIe schematic, pin 8 is N/C and pin 1 is grounded. I guess pin 8 (BE - an active low input) of the W65C02S floats low effectively cutting the CPU off from the system. Tying pin 1 (VPB - an output) to ground is just a no-no, so since it has no use on an A-IIe, off with it!
I may look around for a R65C02 and take the franken-chip out at some point.
If you read the installation book that comes with the Apple //e enhancement kit, you will see that some older software will look kind of funny after the upgrade.
I remember one title that did not with after the upgrade: Randamn.
Fortunately, someone fixed up that game for use in an enhanced iie.
Kudos! It just doesn't feel right having a modded static core chip in there, does it?
Throughout the ages I've tried all the brands:
Rockwell
Synertek
Signetics
WDC
NCR
GTEu
CMDu
MOS
UMC
Sanyo
..and in the Apple II application there is little or no difference in reliability between them.
By the way, my workhorse Apple //e, the one that I did BBS activities and countless gaming on was (and still is) a WDC65C02P-2. Part of the official enhancement kit. So if you come across that part, rest assured it will perform perfectly.
It is notable that WDC designed the 65C02 in the first place.
Maybe Bill Mensch still has one in his parts box. A 65C802 would be sweet too, but where on earth would you find one now, except to ask Mensch?
Hello I will be burning my EPROM's but would like to ask if I can USE R65C02P4's for the cpu?
I am having a hard time getting The R65C02P2's...But Can get the R65C02P4's easier and cheaper...
Thanks In Advance.. Mike
An R65C02P4 is what I have in mine now. It works fine.
I think that if you use the Apple iie diagnostics 7.0 as well as the built in self test that should be enough to find any problems.
Thanks that what I needed to know....
Mike
Hello everyone,
I reopen this OLD post to ask what type (memory size and access speed) for the following EPROMs for upgrade iie to enhanced. That is, which abbreviation should the two types of eprom have?
For CD/EF -> AMD 27C64 ???-??? For Char -> ST M2732 ???-???
Thanks
http://www.applelogic.org/APPLEASICs.html
Thank-you very much!!!!
Burning EPROMs has been something I've been doing for the last year or two. There are many used motherboards that actually come with EPROMs. What's good about using EPROMs is that you can burn the latest version of the keyboard rom, revision D. If you have the last motherboard that came out before the platinum motherboard, it comes with a revision D. But for those with older motherboards, even if you enhance it, you're still stuck with a revision B keyboard rom. What's the difference? I don't know but they are definitely different. If you want the equivalent of a stock enhanced iie motherboard, you must have a revision D keyboard rom.
I use ST M2764A EPROMs for the CD and EF roms and they are magnificent. I also use National nmc27c32bq200 EPROMs for the video rom. I use a minipro EPROM burner model tl866a to burn my EPROMs and these EPROMs always come out ok.