Re: How (does?) SuperCPU 64 control CPU port?

Another interesting CPU replacement cartridge to look at is the "Turbo
Master CPU" from Schnedler Systems. I have one of these and absolutely love
it.  It replaces the C64's internal CPU and RAM with an external 65c02 and
RAM running at 4.09 MHz.

If you need a picture of the inside of it, let me know.  Mine also has
JiffyDOS installed.

/Raj W.

On Sun, Apr 23, 2023 at 5:32 AM Maciej Witkowiak <ytm_at_elysium.pl> wrote:

> Hi
>
> I'm playing with a project that replaces 6510 chip in a C64 with a Teensy
> 4.1 board that emulates the CPU:
>
> https://github.com/ytmytm/teensy64
>
> The emulation can be a lot faster than a real 6510, so I plan to put in a
> SuperCPU compatibility mode eventually.
> The next logical step could be to drop the idea of replacing onboard 6510
> and just put everything on a cartridge.
>
> This got me thinking: how does a real SCPU handle access to $01 port?
>
> I guess that SuperCPU's CPLD can track the writes to $01 and update its
> internal memory config: providing ROM data from its own copy when needed.
> The I/O access might be managed by dropping in/out of the Ultimax mode.
>
> But what about the tape - does that work with SCPU? I don't see any way of
> controlling tape from the cartridge port alone, it has to come from 6510
> $01 port.
>
> Or perhaps SCPU works using a different principle and the onboard 6510 is
> sometimes running?
>
> ytm
>
>