MITS 2SIO serial chip?

From: ajp166 <>
Date: Mon Dec 17 22:49:06 2001

From: Ben Franchuk <>
>I suspect this is because
>1) All registers but the PC are 8 bit.

Total number of bits including storage for status were about 1/3
that of Z80 (208).

>2) Instructions grouped into fewer internal states per clock.

Yes, and instructions were simpler in construction. Some Z80
instructions like the block moves and searches (ex LDIR) and
a complete set of IO instuctions (not present on 6502) made
for a great difference in size and complexity of the instruction set.

> I think a z80 instruction could have 17+ states where a
>6502 used up to 5 states.

Actually Z80 went as far as 22states.

Received on Mon Dec 17 2001 - 22:49:06 GMT

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