ROM in an REU

From: Niklas Ramsberg (
Date: 2003-01-07 21:37:14

Hej allihopa!

Now that I have an EPROM programmer I want to stick EPROMs wherever I
can. :-) 
So I was thinking of using the empty socket in the 1750 REU for a 27C512
chip where I can switch between two 32K banks. One would be used to
house some utility for the C128, the other would hold a C64 program.

Which jumpers should be closed (except for J2 which tells the computer
it's a 32K chip) for the C128 to recognise the ROM in both native mode
and C64 mode? Is it possible at all?

I would like to use the C64 bank for Tron/FLT's version of Turbo
Assembler, X-asm 3.3 ( Is
it possible to put an unmodified version of the assembler in the ROM,
and have a routine in the ROM that transfers the assembler to its proper
location in RAM and then starts it? Relocating it to run from inside the
ROM is a little beyond my programming skills at this point.

I read an old discussion on the list regarding KeyDOS and a request for
a "light" version with Ramdos only. I would be very interested in having
that in the C128 part of the ROM. Did anything ever come out of that
discussion? I really don't feel any need for a full KeyDOS since I
already have installed The Servant as an internal function ROM.


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