Re: about accelerator chips/cards

[damage_x@hotmail.com]

Michael J. Mahon wrote:
>
> An accelerator using the same principles could be used for almost
> any machine, but the ones designed for Apple II's are specialized
> in the way that they are controlled.

I thought it was interesting that they actually had cache RAM attached
to a 65xx. The 65816 upgrades for the C=64 simply run at 1MHz in the
old 64K address space and run at 20MHz when working above 64K. Alas the
Atari 8-bit world doesn't seem to have any sort of standard CPU
upgrade.

>
> The modes and registers in the Rocket Chip (and the Zip Chip, of
> which it is a clone) are accessed by multiple references to certain
> addresses which are mapped to I/O space in the Apple II.  And the
> chip monitors certain I/O addresses to slow down for sequences of
> instructions which are timing-critical (such as 5.25" disk access in
> the Apple II).  These features are specialized to the Apple II
architecture.

So software on another system with a different memory map could
accidentally mess with the chip config...

>
> Under the right conditions, one of these chips might work in another
> 1MHz 65C02 machine, depending on whether speed-critical routines
> were involved and how the address space was allocated.

Would it have to be 1MHz or is the accelerated speed derived from the
1MHz perhaps?

Any differences with the cards vs. the chips?

>
> -michael
>
> New Applesoft BASIC interface for NadaNet networking!
> Home page:  http://members.aol.com/MJMahon/