If you run the processor at a faster speed code like that would break
anyway. There's only one piece of code I've written that would work
that that way that I can remember. It was for programming FLASH
memory, the delay loop was based on instruction cycles. I had
considered using the timer but a short deadline prevented that. New
FLASH chips let you poll a register on the chip to see if it's
ready... something that is much safer.

I want to build myself a 100+MHz TRS-80 with extra RAM just for the
heck of it. I want to add a software switch that would allow me to
select the CPU speed for compatibility or high speed. LOL, a
"TRASH-80" at warp speed I guess. I wonder if there are any open
source designs for comact flash or secure digital. A micro drive
would make a great hard drive for something like this once someone
writes the software.

--- In zxgate@yahoogroups.com, "Andrew McMeikan" <andrewm@o...> wrote:
> The instruction timing is different.
>
> It could be done, it would take a lot of work.
>
> I guess if it was slowly migrated it would be handy, some of my z180
> code
> would be seriously broken over timing issues (instruction and wait
> state etc
> would all have to be accounted for)
>
> MMU and other peripherals would be a straight bonus for use with the
> existing z80 core, the only immediate instruction would probably be
> the
> out0.
>
> cya, Andrew...