Apple Z80 softcard settings?
Ernest
settings are. Does anyone know:
1. The dip switch settings (4 little switches.)
2. Which slot this card goes in?
3. What the command is to activate this card so that it will boot CP/M?
Thanks for your help.
Ernest
Paul Schlyter
Ernest <leuco...@seanet.com> wrote:
> I have a Microsoft Z80 Softcard for an Apple II but I don't know what the
> settings are. Does anyone know:
>
> 1. The dip switch settings (4 little switches.)
I'll be able to access within a week or so, if you're interested. It
has to do with the memory mappings of the Softcard memory space vs
the 6502 memory space. The default positions were all 4 switches up,
as far as I remember.
> 2. Which slot this card goes in?
usually free. Slot 0 is often used by RAM cards, slot 1 by printer
cards, slot 2 by serial port cards, slot 3 by 80-column video cards,
slot 6 and sometimes also slot 5 for disk controllers. This left
slot 4 as the most commonly free slot, and thus the Softcard was
recommended to be put in that slot. But you could really put it into
any free slot except slot 0.
> 3. What the command is to activate this card so that it will boot CP/M?
disk and boot it.
The machine language instruction to switch CPU (which was embedded in the
boot code) was an I/O instruction (a read) to the first I/O address within
the 16-byte I/O space associated with that slot: if the 6502 accessed
this address, it would halt and the Z80 would start (from address
0000H the very first time; later from where it last was stopped), and
of the Z80 accessed that address, it would halt and the 6502 would
start.
The boot sequence of the Softcard consisted of a lot of 6502 code
which read in low-level disk I/O routines (the Apple CP/M equivalent
to the RWTS in Apple DOS) in 6502 assembler, plus some I/O drivers in
both 6502 and Z80 code, and a Z80 bootstrap. Only when all this had
been read in, the 6502 did halt and the Z80 did start. Later the
6502 would be used for some I/O activities (such as disk reads and
screen output: keyboard reads and serialport I/O was often done
with only Z80 code though).
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Ernest
switches set to down (off.)
What a great card!
Paul Schlyter wrote in message <87konf$4dr$1...@merope.saaf.se>...
Paul Ryan
given the card and never been able to try it, as I don't have the CP/M
boot disk for it. Anyway my 80 col card does not work, so it would be a
bit pointless!