All,
This is kind of a silly question but it has been bothering me.
I have two apple //e 's (badged and verified the motherboards), but one boots up with the expected banner Apple //e but then the other one boots with Apple ][
Both work like IIe's lower case, applesoft in from, etc.
Anybody able to tell me what is causing the difference?
The ROM is the difference. The original ROM displayed "Apple ][". The ROM that came with the "enhanced" machines displays "Apple //e". The "enhanced" machines also came with a 65C02 (instead of 6502) and also replaced the video ROM.
MacFly summed it all up. Also if you do a system self test the enhanced system (the one that says iie) it will say “system ok”, the unenhanced system (the one that says Apple ii) will say “Kernel ok”. If you do decide to enhance it hold on to your unemhanced chips.
Oh wow never realized. The //e that says Apple ][ was mine from Jr. High school. Not sure where the second came from.
Or look into some of the newer ROM replacement products that will allow switching back and forth between the ROMs. Of course that still won't switch back from 65C02 to 6502, but it may allow a few programs to run that fail on an Enhanced //e if it is only ROM compatibility issues.
There is almost zero programs that will REQUIRE the presence of the 6502 instead of the 65C02.
In the old days it was popular for a time to replace the 6502 with a 65C02 in an un-enhanced IIe to allow you to run software that required the extra CPU opcodes in the 65C02 while keeping the character set of the un-enhanced IIe.
Don't throw away that 6502. There are a lot of II+ owners that may covet it when eBay supplies dry up or Chinese fakes start to dominate those chip sales as well.
Echoing what baldrick said.
To be honest, despite it coming with a normal 6502, I use a 65C02 on my Apple 1 clone on purpose, not necessarily because I'll ever use the features, but because I always read that it is uses 10 times less power than the normal 6502. When mA are at a premium, it's a no brainer to me.
I suppose you could write some cheeky code to use those extra CPU functions on your Apple I, save the program to tape and confound your Apple I friends!
The early MOS 6502 has a power supply current of typ. 70mA, max. 160mA. This is "official" data from the datasheet.
Later 6502 from Rockwell, Ricoh, GTE, Synertek, UMC etc. need less power. Estimated 30...50mA.
The typical CMOS 65C02 is specified at 2mA per 1MHz.
There is one program I found that doesn’t support the enhancement chips. VisiCalc iie. Runs but the character sets are wacky. There is however an image of “Advanced VisiCalc” on 3.5” that DOES support the enhancement . I guess if your a die hard VisiCalc user. But yes I would agree there is software out there that requires the enhancement. If you’ve got 2 working systems just have one of each. I have 2 enhanced iies and 1 1982 revB unenhanced.
Just looked at the mother board and this apple has a Rockwell 338-6503 processor in it.
Never heard of the 6503....
Apple name for a Rockwell 65C02
I have a 6503 in one of my enhanced iies. Scratched my head when I saw it at at first. Just a 65c02.
Or get the ROMXe so you can instantly switch between enhanced and un-enhanced. And also get extra fonts, Reat Time Clock, and instant booting into DOS, ProDOS, or other applications. It will also eliminate the false boot issue that sometimes occurs if you power cycle the computer too quickly.
There's really no programs that used the undocumented opcodes in the 6502 that breaks with 65c02?
There are at least a few games that won't run on a 65C02, but that's not very common. I used to know a couple examples but my memory has faded. And a couple of them it was only the original copy protection -- cracked copies would run.