10 Sep
2023
10 Sep
'23
6:19 p.m.
On 9/10/23 09:44, Liam Proven via cctalk wrote:
No idea of the CPU performance. 4MHz Z80A but whether
there was any
contention or anything I have no idea. I believe one of the
interesting bits of the design is that there's no ROM at all. They
came with a dedicated printer (as well as a Centronics port) and
masked into a corner of the printer controller chip was a tiny bit of
bootstrap code.
From my PCW tinkerings--I bought it for the CF drive, so it was mostly a
curiosity with me. I think the base unit (120VAC) was sold by Sears in
the US for a time. I grabbed one locally and upgraded the RAM to 512K
and a 3.5" 720K drive (Teac FD235F)--the READY line is required for
operation. I noted that changing a single byte in the boot code enabled
support for DS media.
But the "no ROM" claim should probably be modified to "no discrete
ROM",
as I believe the boot code is contained in the printer controller and is
strobed onto the Z80 bus at IPL time. Almost certainly mask-programmed.
The PCW, although interesting languished in my shop for about a decade.
Finally was contacted by someone who was willing to drive up from
California and relieve me of it. He also received an AT&T 6300 for his
troubles. I am loath to recycle old interesting gear, but am willing
to give it away to interested parties.
--Chuck
--Chuck