On 06/17/2010 11:18 AM, datajerk wrote:
After a Google I take it that this upgrade gives me 8MHz (not needed, is it software switchable?), Z80 (what MHz?), a clock, and 1MB. I am most interested in the Z80 and clock, but the rest is nice too.
The Z80 is almost certainly a functional clone of the original Microsoft Softcard. That implies that it needs a host processor running at the stock 1.x Mhz. speed. I haven't installed the unit yet, but unless they're doing some sort of magic I bet you need to disable the Zip acceleration before booting CP/M.
The Z80, in turn, runs at approx. 2Mhz. average speed. IIRC, it sort of "stutters" up and down between motherboard refresh intervals (I'm sure somebody will correct me if this is wrong:-) ).
You wouldn't want a rig like this for any real work under CP/M. For that, I recommend a //e with ZipChip running a hot-rodded Applicard (8Mhz), a CardZ180 (9.12 Mhz. Z180/64180 with 1 Meg of private memory) or a Freed Z80 card running at 20Mhz. The last of these is just stunningly fast in a zip-chipped //e.
Steve