15 Nov
2013
15 Nov
'13
10:29 a.m.
On 11/15/2013 09:36 AM, dwight elvey wrote:
As I recall the NSC800 was a Z80 on the inside but a
8085
on the outside.
I would guess that all but the low level disk could be regular CP/M
or Z80 improved CP/M. There are several books on CP/M that
will help you figure how to build a boot disc. I don't recall the
name of the book I used to build a boot disk, years ago.
Dwight
I always worked from the standard "CP/M Alteration Guide'. But all of
this suggests that the peripheral interface characteristics are
known--and it's not clear that this is the case.
The NSC800 is a chimera--Z80 instruction set. More or less an 8085
multiplexed bus interface, half-IRQs like the 8085, but the TRAP vector
is to 60H, not 24H, uses port BBh (but only with indirect I/O
instructions) as a feature control.
--Chuck