For fun I have knocked up an interface to connect a 2732 EPROM to my Apple-1. It all works fine, can see what I have programmed into it on the monitor and have loaded the A1 assembler into rom and that runs perfectly :)
Now, apple basic sits at E000 which would be easy to change the select line for that bank of ram to make the eprom sit there instead.
I suppose I have a couple of questions, does anyone have a binary or Intel Hex copy of Apple basic and would it work ? (I have no idea if it just uses the 4K ram from E000 to store the program or if it uses it for data at all)
Ok
So found a binary file of Apple-1 basic, converted it to Intel hex and blew it into a 2732 EPROM
Repatched the RAM from E000 to 1000 and the EPROM from E000 and it works.
Basic without loading from cassette. Need to test if I can still load programs and if the ACI works with the EPROM interface (its whats known at work as a DWI, a dangly wire interface at the moment).
So startrek loaded with no problems and runs fine.
I'm sure this must have been done before, but couldn't find it on searching.
So the plan is, a small riser card from the internal slot to take two horizontal cards. One being the ACI and the other carrying the BASIC ROM and maybe a second bigger ROM with the remaining chip select on the bus going through a hex selector switch to switch banks in as required.
Time to crack out KiCad
I made some of these a few years ago. They are such a time saver I never remove mine.
https://www.applefritter.com/content/apple-1-basic-rom-card
Very cool!
Keep going!
Bill
Hi Gary C,
good job, you are basically re-creating my Juke-Box Card... :-D
https://p-l4b.github.io/jukebox/
...which is the precursor of the new microSD Card (with built-in nippur72's SD-OS):
https://p-l4b.github.io/sdcard/
I found both projects very educational and challenging, I'm sure you'll have fun with your.
Enjoy! :-)
Claudio - Plab
Very nice Claudio
and yes, the fun is in the doing.
Its exercising pathways that haven't been used in quite a while :)