So happy to see some love sent the way toward my beloved 200. While I do
have various 100/102s in my collection, the 200 it the one I use due to
the screen size.
Unfortunately, I live in the US so I won't be able to get a rexcpm once
it becomes available.
I hope to get my hands on the 5mhz upgrade though. As much as I love writing
on my 200, it can get really sluggish after the file gets past 5k in size. I've
had to work around this by chopping my files into smaller chunks to get
around dit. It would certainly be nice to fill a bank with one file versus a
dozen.
I've been known to fill all banks a few times on a single writing project.
can get a bit ridiculous. But anyway, will there be any possibility of the
upgrade being available to those of us in the US?
Daniel
sysop | Air & Wave BBS
finger | [email protected]
On Sat, 31 Jan 2026, Stephen Adolph wrote:
hi all,
Here is an update on my long standing project to get CP/M running in a T200.
This morning I have CP/M installed and running for
the first time!
The first pic is an attempt to photograph the LCD. It is faint, but you can see
CP/M is there, the drive is working and the
standard files are present. This hardware is my T200 test bed which is a
wooden structure that holds all the parts more or less
where they are supposed to be, but I can access the internals easily.
20260131_092239-1008x756.jpg
CP/M on T200 works the same as in M100. External screens are supported on the
cassette style or BCR style of connection. Second
pic is a zoom out showing the test hardware.
20260131_092117-756x1008.jpg
In order to get this working, I needed to re-design how REXCPM operates to
accommodate the Tandy 200 RAM differences. The T200
only has 24K RAM banks as you know. The option rom provides 32k range from
0000-7FFF, but the address range 8000-9FFF is actually
available as well as part of the option ROM allocation. So REXCPM had to be
changed to function in this context. Specifically,
the A15 signal is needed by REXCPM to distinguish the 8k ram block from the 32k
option rom, so a new wire has to be brought out
from the motherboard. It is an easy connection. So, this is a plug and play
upgrade requiring a single jumper wire to be
installed.
In order to get this pulled together, I modified VirtualT to support Tandy 200
with REXCPM. This was a big piece of work on its
own, but critical to debugging the system. Kudos to Ken and all who have
contributed to VirtualT... absolutely critical to this
project.
Also, Philip Avery provided the source code and tools for generating M100 CP/M,
which I have now updated to support the T200
variant. Thank you Philip! Without your hard work in CP/M, this would not
have been possible.
PC-8201 is included in this effort. I have CP/M running in VirtualT for
PC-8201 now, and will build the hardware and test that out
shortly.
Last pic- if you zoom in you can see I have a 5MHz upgrade also running on this
hardware. It is a small PCB mounted on top of the
CPU.
image.png
Thats it for now.
Steve
