Hi,

first of all, happy new year everyone on this
list. I'm the one who makes the hardware of
Chameleon, just in case my name is not familiar.

At 21:33 07.01.2009 +0000, Mark wrote:
>Hi there,
>
>Well I'd buy it just for a FPGA on a cart .. so there you have one
>customer! :-)

Good - then you might also like to hear that the
cartridge will also work stand-alone (that's why
it'll have the PS2 keyboard connector).

>So if the 6502 and VIC cores are accessing their own private RAM on
>the cart, can they get access to the memory space of the real C64 ?
>Or do they have to page it in via something like a REC ?

The internal C64 memory is completely switched
off. You can remove it, if you like. The C64's
VIC reads its data from the Chameleon ram, which
is the major difference to any accelerator out
there. While all other accelerators have to slow
down to poke into the C64 memory, Chameleon does
not have this "penalty". The one thing where
Chameleon has to slow down is a write to colour
ram, this cannot be replaced externally.

>What about peripherals ? (joysticks, user port devices, devices on
>the serial bus etc) Would you have to page the carts RAM down into
>the the C64 RAM, then have the real 6510 pick up where the 6502 core
>left off and access the device, copy the data into the C64 RAM and
>then have the 6502 core take over again and page the data from real
>RAM back into the cart and process it .... my head hurts now :-)

No need to - normal bus access is still possible,
so the 6502 inside Chameleon can read/write CIA
and all other registers as if they're local.
Other accelerators also don't have problems
accessing SID, VIC and CIAs, so why would Chameleon have a problem?

And yes, it's truly a fun project. Lots of things
to learn about a machine that is considered to be "well known" ;-)

ciao,
--
Jens Schönfeld