It is a bit tricky because the system bus behaves differently in M100 vs any other model T.
The M100 is certainly my favorite as the system bus can be really used, with a pcb nicely contained in the bay. The best port to use for storage is still the serial port though. Common for all model T. What I dont like about the system port, is that it does not lend itself well to connections to the outside world. What would be interesting is the use of REXCPM, not as a combined REX plus CP/M solution, but as a REX with a huge ramdisk dedicated to local file storage. This is something that is difficult to do in flash imho, but very doable in SRAM. The DOS development is the long pole in that tent as the hardware is done. But in such a case, the system bus only gets used to provide a few signals to REX as opposed to something more meaningful. On Saturday, August 1, 2020, B4 Me100 <[email protected]> wrote: > Historically there have been quite a few pieces of hardware designed for > the expansion bus, especially for the M100. I have an 1990s version of a > battery backed 128K SRAM bank that can be used to provide several banks of > switchable memory. So the bus has not been totally ignored :) > > Two+ years ago I started a project to build a modern DVI using the system > bus, the final design worked well but was not easy to produce - lots of > components that did not lend itself to hand assembly. It included not only > DVI functions but WiFi, extra serial ports and a PS-2 keyboard interface. > Last year it was totally redesigned and greatly simplified, losing the > WiFi, PS-2 etc. So now I have a microDVI board the size of a 40pin IC > which plugs into the expansion port of the M100 and can be attached to the > T102/T200 external port via an adapter board. This is a much more tenable > design for hobbyist assembly only a handful of components are required. > > The new board provides full DVI functionality including video to a VGA > port and virtual twin 180K disks that can be booted with DVI DOS. The > virtual drive uses virtual floppies (on an SD Card) which can be swapped, > formatted, read, written etc just like the regular DVI. Files can also > be extracted and imported from the virtual floppies to aid movement > from/to the SD Card. The VGA provides 8 colors with the option to draw > lines, rects, circles etc. if you want it, as well as the 40/80 regular > char display. In addition to this the board now runs a TPDD drive and > having patched the M100 TS-DOS OPTROM (will not work on the T200) to use > the system bus the board can act as an internal TPDD drive - which is way > more useful than the DVI floppies and quite fast for software loading. > Currently the project is a bit stuck due to lack of time/resources etc. > But the plan was/is to produce a video driver for the M100 such that it > can co-exist with TS-DOS and possibly/maybe extend the DISK DOS to include > new BASIC commands to draw on the VGA screen. Then to add a DVI MGR tool > to manage the virtual DVI and TPDD drive. The board also sports a USB > socket so it could be used to provide very fast comms with the appropriate > software on the M100. The SD-Card possibly qualifies as modern storage, > but no Dropbox :) > > Originally my thought was to solicit some assistance from the wider M100 > community and see if there might be anyone interested in producing the > necessary utility tools to run on the M100 as well as help debug the DVI > board itself, however a virus seems to have curtailed many options. > > SoS yes at least one thing that I know of is being worked on if very, > very, very slowly. > > > On 31/7/20, 1:52 PM, "M100 on behalf of mark audacity romberg" > <[email protected] on behalf of [email protected]> > wrote: > > >With as many upgrades and hacks (NADSbox, REX, VT100) as we have for the > >M100, I¹m really surprised not to have seen anything done with the > >expansion bus connector. Seems like a DVI clone would be achievable, or > >internal removable storage or a VGA interface, or or or. I would love to > >be able to have a modem and a mass-storage device connected at the same > >time, for example. > > > >Is this something folks have been working on and I¹ve just missed it? The > >desktop Tandy guys have got Dropbox clients and flash disks and all kinds > >of whiz-bang stuff for their machines! > > > ><mark, KF5YDR > > >
