Hi,

--- In chameleon_64@yahoogroups.com, "strandedinnz"
<strandedinnz@...> wrote:
>
> I think you can be excused for having a real life :-) After all
the old C64s and 128s are
> just a fun hobby for us all now.

Since when is programming FPGAs not 'real life'? :-)

>
> So how are you turning off the real VIC and 6502 so yours can take
over ?

The VIC-II can not be turned off. Turning off the CPU (which is a
6510 btw) is easy. Just pull the DMA line low.

>
> Does the 6502 and VIC cores have to access the original memory in
the C64 ? Or will they
> have there own local RAMthat they'll work with ? .. which I think
is how the SuperCPU does
> it .. has fast RAM on the cart which it can then mirror into
the "slow" RAM of the C64when
> the VIC needs to access it ... i think ...

No. Yes it has 8 Mbyte on my prototype but probably more on the
retail version. You are correct that is how the SuperCPU does it.

Take note that Chameleon is not a SuperCPU look-a-like, not in its
purpose nor its features (the turbo is more lika a bonus). The way
that it works is completely different.

>
> I'm just starting dabbling in the FPGA swimming pool, have a
Altera Cylone board and so
> far can make LEDs flash!! Wooohooo I'm a VHDL GOD!!! ;-)
> Maybe one day I can do something useful in life :-)
>
> Pity about the no C128 support .. would have been interesting
having a 3 CPU Commodore
> but no matter, maybe one day.

It depends how you count cpu's. Depeding on interpretation of the
word 'cpu', Chameleon already has >3 CPUs ;-)

The problem with the C128 is signal quality. The main PCB of the 128
(especially the D version) is very large. This results in delays in
the signals and degraded waveforms forms on the expansion connector.
And ofcourse the C128 is a beast with feature creep itself.
So this 'maybe one day' is somewhat unlikely, unfortunetly.

>
> Do keep it simple for starters though, to many projects catch
feature creep and end up
> impossible ... hell even just a cartridge with an FPGA attached to
all the right lines would
> be a great start, would let you add or remove whatever
functionality is currently in
> development.

The schematics and pin list will be made public. So the chameleon is
indeed a fpga-on-a-C64-cartridge. I wonder how many people would by
it for that reason however...
Feature creep is a concern, but because of the flash-rom, updates
can be relased later that can easialy be loaded from MMC card and
installed.

Peter