Re: C64 buses when RESET is asserted

From: brain_at_jbrain.com Date: Mon, 8 Apr 2013 14:30:34 -0400 (EDT) Message-ID: <1225239306.818353.1365445835005.open-xchange@email.1and1.com>

> On April 8, 2013 at 1:54 PM Michał Pleban <lists@michau.name> wrote:
>
>
> Hello!
>
> Jim Brain wrote:
>
> > I still think your idea is fine, just just need to isolate the ADDR and
> > DATA bus of the ROM from the PCB socket while you are updating it. I
> > think the PETVet does something similar, though it's doing it on the CPU
> > socket, not the ROM socket.
>
> Yes of course. But if I need additional chips to isolate the buses, it
> will be easier to use a Flash chip instead of SRAM, and make the 6502
> update it with data pulled from the SD card...
Well, if the additional HW is not too much, I'm happy to add it to ROM-el.
 People have asked for such a capability many times.  I think I ran into
problems finding the correct select logic, as /OE and /CS on the ROMs are not
active on a write cycle to those areas of memory.

Jim
>
> Regards,
> Michau.
>
>
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