Speedupbas Transmitbas
TRSLINK.BAS »
the emulator program itself the Model I character set copyright & registration info installation & config program converts Level II ROM for use with MODEL1.EXE the manual
a Model I virtual disk containing some public domain programs MS-DOS program to receive Model I ROM or disks from TRS-80 via parallel port (used with TRSLINK.BAS) patches Model I ROM to remove some built-in delays Model I BASIC program for sending Model I ROM and disks through the serial port
Model I BASIC program to send ROM and disks through parallel port
Before we get to meat of this article, let me freely admit that if you don't own a PC clone of some sort, the following will only be of limited interest to you. What we have here, my friends, is the very first MS-DOS article published in TRSTimes.
Now, why would we, faithful devotees of Models I, III and 4, publish such material? Read on, and you'll see how the 386/486 machines have finally been made useful and fit for TRS-80 consumption!
The whole thing began when Art McAninch uploaded a file to the TRSuretrove BBS. It was called 'MODEL1/ZIP, and was in MS-DOS format. Art's description of the file was something like 'emulate a TRS-80 Model I on your PC'.
Hey, that sounded interesting, so I downloaded the file. After transferring it to my 386, via SUPERCROSS, I 'unzipped' M0DEL1.ZIP into a directory called MOD1 on the hard drive. I then began to examine the files that had been stored in the ZIP archive.
The manual, MODEL1.DOC, begins by describing what the author, Jeff Vavasour, has done:
"This emulator package allows your MS-DOS based PC to run as a TRS-80 Model I. It will be able to run virtually all Model I applications and software from Galaxy Invasion to Electric Pencil and the Z-80 Editor/Assembler. My aim was to be able to design a convincing 'virtual reality' in which a Model I program would not be able to tell that it was not running in the genuine machine. This virtual Model I includes the following options:
- 48k CPU with Z-80 microprocessor
- Expansion Interface (including internal clock, printer port, and floppy disk controller)
-RS 232 port
- 4 80-track single-sided disk drives
- Lower case and numeric keypad upgrades
This emulator requires CGA, DOS 2.11 or better, and at least a 7MHz clock speed, though a hard drive and at least 16MHz is strongly recommended."
Reading the documentation, I realized that the emulator needed one item before it would work: the Model I ROM. Obviously, Jeff could not legally provide this sotware, as it is copyrighted material. However, he provides you with two methods of transferring the ROM from your Model I to the PC yourself.
The first method connects the two computers via modems (or a null modem) and then uses TRANSMIT/BAS to send the ROM image to the PC. The TRANSMIT/BAS program is also capable of sending entire disks.
The second method requires construction of a special cable so the computers can be connected via their printer ports. Complete instructions are given and, according to Roy Beck, the cable is simple to make.
At this point, the ROM has been transfered to the PC and when we execute MODEL1.EXE we can play in Level II Basic. We now need to transfer our Model I DOS or DOSes, using the same methods as above.
Once we have our favorite DOS ported to the PC, we can then begin to investigate the emulator. Jeff has done an excellent job - what you have before you is, indeed, a Model I with a very good monitor. Even the keyboard has been configured to emulate the Model I. For example, Shift 2 is now " (quote). The included program. SETUP.EXE, allows you to configure the keyboard to your liking.
So, what's the bottom line? To a PC user who has never been involved with a TRS-80, the emulater will be of little or no interest. But, if you grew up with the Model I, this is a MUST have program. It is fun, fun, fun. I have spent the better part of a week just playing with it. Even got DANCING DEMON to work. Yes, the emulator has real TRS-80 graphics. Jeff drew the entire TRS-80 character set from scratch.
Though the entire package is shareware and can be obtained free of charge from Roy Beck's TRSuretrove BBS in Los Angeles (213 664-5056), I strongly recommend that you send Jeff Vavasour a $25 registration fee to keep him programming this type of thing. Sending him the registration fee entitles you to an upgraded version with the following additional features:
SOUND! Many TRS-80 games used the cassette port to generate sound and speech. Now this output is routed to your PC's internal speaker. Sound may be turned on or off using F4. (You can even listen to CSAVE's if you like!)
SPEED! The registered package is a newer version of the emulator. It runs at up to 2.5 times the speed of version 2.05 (the shareware version). For software that runs too fast, a speed control is provided with the F3 option.
SNAPSHOTS! The registered version of the emulator can save and load "snapshots" of the TRS-80's memory and status. This is the "virtual cassette" option. You can save programs or games-in-progress and retrieve them instantly at any time. You can even exit the emulator or turn off the computer and come back right where you left off the next time you run MODEL1! Snapshot control is provided through the F3 menu.
You will also receive the source code, and be placed on an e-mail mailing list (available to Internet users) so that you may be notified of new developments.
To register, send $25.00 to: Jeff Vavasour c/o Department of Physics University of British Columbia 6224 Agricultural Road Canada V6T 1Z1
My $25 is in the mail, and upgrade.
look forward to receive the
That was the review portion of this article. Now let me ramble on by chronicling some of my experiences with the Model I emulator.
As some of you know, I am not a hardware man. As a matter of fact, I avoid anything that even remotely involves a screwdriver. So, when the manual recommended constructing a special cable, I knew that this method was not for me. (I did manage to talk Roy Beck into making it - and present the project at the next VTUG meeting -1 loook forward to that.) I also knew that I was not about to move my Model I or my PC so I could hook them up to separate phone lines - and I don't have a null modem. I was curious about the program, and I did not want to wait the two weeks until the VTUG meeting, so I began to think about another way. ! am lucky enough to have a Model I, Model 4 and a PC, so transferring files from the Model I to a PC is not a problem.
The first step was to write the ROM to a file. I fired up the Model I with LDOS 5.1.4 and tried the DUMP command. Unfortunately, DUMP will not dump anything below 5500H. Now, I know that there is a patch somewhere to defeat this limitation - we may even have published it in a previous issue of TRSTimes - but I wanted to do it NOW, not run off somewhere and look in file cabinets. I realize that I could have block moved the 12K ROM code to an address higher than 5500h and then dumped it to a file, but I chose to write a short assembly language program to do the task- quick and dirty.
¡GETROM/ASM
¡copyright 1993 by Lance Wolstrup ;for TRS-80 Model I - using LDOS 5.x.x ¡writes Model I ROM to disk in drive :1
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