1 Feb
2012
1 Feb
'12
8:03 p.m.
On Wed, Feb 1, 2012 at 7:21 PM, Jim Brain <brain at jbrain.com> wrote:
Barring implementation of 65SPI on a CPLD, is there a
quick-n-dirty way to
wire up a SPI-based module to an Apple II/II+/IIe? ?I'm looking for a temp
solution, while I design a Apple II board with a correct interface.
?Something that doesn't require any soldering would be grand (bit banging
the SPI via some IO pins, Using the DSR/DTR/RTS pins on the RS232 (if that
can be done...), etc.
We used to do bit-banged serial at 1200bps from the pins on the Apple
II joystick port (the DIP socket near the back corner). We did it to
move blocks of data from an Apple disk to a Commodore64 disk (which
already _had_ a TTL-level bit-banged serial port on the User Port (as
I'm sure you know), so that end was "free") Once we worked out the
sector skew, one-by-one, we copied the blocks containing the game data
(that we would now recognize as a .z3 file) for Sorcerer on the Apple
to overwrite the correct blocks on the C-64 version of Enchanter (same
game engine) to play the game there.
Unfortunately, I did not write the Apple II end of things so I don't
know the intimate details, but the important part was just stuffing
two wires (GND and TTL TxD) into the socket and running that to GND
and TTL RxD on the C-64 User Port.
A quick inspection of the Apple II schematic or technical manuals
should show what bits are writable and what address in the $Cxxx block
will trigger them.
-ethan