C128 and 8MHz Z80

From: Nicolas Welte (welte_at_chemie.uni-konstanz.de)
Date: 2002-07-09 12:33:44

Recently I got something that might be quite interesting: a small PCB that
boosts the Z80 in the C128 to 8MHz. It has the name Rossmöller on it, this is
the same company that made the C64 Turboprocess 4MHz card. 

The PCB has a GAL on it, and it has two wires: one gets the 8MHz dotclock
from the 8701, the other an 1MHz signal from one of the bus buffers (I guess
for synchronisation of memory accesses). The GAL also connects to the
previously unused Z80 signals that control memory access and wait states. So
it can run at 8MHz unless it needs memory access, while in the original C128
it uses 4MHz during one half of a 1MHz cycle (does anyone know if it can use
both 1MHz cycles in fast mode?).

I'd like to run some Benchmark tests on this thing, are there any standard
programs for CP/M I should use?

I also need to get that GALBlast built (have all parts already), maybe the
GAL isn't security fused and I can read it out.

BTW, I have a picture of the device online:


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