23 Dec
2010
23 Dec
'10
8:46 p.m.
On Thu, 2010-12-23 at 21:47 -0600, Jim Brain wrote:
As such, I would like to investigate the ability to
design a newer
CP/M cartridge that will work with both the C64 and the C128, runs
much faster than either the CP/M cartridge of the internal Z80. It
could be simply an exercise in academics, but I thought I would at
least inquire if others had any interest. The items I feel are
interesting about such a design:
* The ability to use the C64/C128 as a second processor to handle
IO.
* The ability to tri-state the Z80 and stop the clock, to allow
the
64/128 to process a "message" created by the Z80 environment.
This would provide valuable information on how to interface a
second processor to the C64 bus.
* The ability to design a unit that could not only function as an
add-on for the CBM line, but also function as a standalone unit.
Jim
You might not even need to stop the Z80 at all. If it had its own
memory, you could tack on a register file to communicate between the
Commodore and the Z80 (say some 74LS670's), with an interrupts mechanism
to indicate a new message. This might even allow the Commodore half to
be reset, leaving the Z80 alone, so you could drop back into C64 mode
and reconnect to the Z80 later.
Alexis.