TRS80 Model 1 emulator

trs80 model1 level2 The Trs80 model 1 level II was my first computer in 1978 and I have worked on it for many years. I upgraded it to 64 Kb ram by piggybacking the ram chips and I did the lowercase modification. My TRS80 had some extra buttons on the backside for the modifications I did, but I never owned a expansion unit and I never had disks. It was a 64 kb TRS80, with lowercase mod and a joystick interface and a cassette player / recorder for loading and saving programs. I wrote a lot of programs in these days, in Basic and assembler. My TRS80 machine broke and was stored in the basement and on one of my moves to another house it got lost. I still write programs for the Z80 and I have written a good emulator and programming IDE with CP/M emulation and so the idea for building a virtual TRS80 was born. There are several good emulators, but mostly not in a true Window (most of them are console applications) and most of them emulate an awful lot including the cassette and disks (even with the original sound) and the waiting for a program to load for more then 10 minutes. These are the true FULL emulators that emulate the old hardware including all the faults. These programs mostly do not include roms and they have a lot of settings, I used them but the lot of settings and the painful loading was annoying to me. I like simple and easy to use portable programs that can be used out of the box. And so this TRS80 emulator was born, it is a easy to use emulator that will give you the experience of using the old machine, but with modern loading speed and cassette tapes on the PC storage. On this page I will tell you what it is, what it can do and also what it cannot do. Regards, Hein Pragt.


I respect copyright and I will not distribute illegal software. But this program includes the model I and III roms, and the zip file includes a lot of cassette tapes of old programs that still might be copyrighted. BUT in my opinion the copyright was from 40 to 45 years ago, these products have not been on the market for a lot of years and I think that for instance Microsoft would not care if someone was using a 40 year old basic interpreter on their own Windows 10 machines. As for the tape software, I feel the same, I do not ask any money for this package and the main goal is to keep the old spirit alive. I anyone can identify him or herself as a legal copyright owner and has problems with the distribution I will remove that content. But I seriously believe there is no one to object to distributing these old artifacts as freeware. My program itself is closed source but freeware.

What is inside this emulator

TRS80 emulator

This emulator is exactly like my own old TRS80 computer with one added extension and that is the Model II roms.

  • Emulates: TRS 80 Model I level 1 and level 2 and the Model III computer;
  • Basic: Level 1 (4k ROM) / Level II (12k ROM) / Model III (14k ROM);
  • Keyboard: 53 keys emulated by the PC keyboard;
  • CPU: Zilog Z80 / 1.77 MHz, the speed is recalculated to match the old hardware;
  • RAM: 64 kb;
  • VRAM: 1 kb;
  • Textmode: 32 x 16 of 64 x 16;
  • Graphics: 128 x 48 pixels, screen is resizable;
  • Color: Black and white on green with screen;
  • Sound: Emulated on PC hardware from the cassette port;
  • I/O: Emulation of the Joystick on thge arrow keys of the PC and the spacebar;
  • OS: No disk and no DOS.

TRS80 emulator menu 2

Casette I/O

One of the things that was annoying in the old days was the waiting for a program to load. This could easily take up 5 to 10 minutes and most of the emulators use the internal old rom routines to read cassette tape files. Even first loading a tape, then type cload and then press play on the virtual cassette recorder. It is like he original experience but I did not like that. So I patched the roms to reroute the CLOAD and CSAVE to my own Windows routines that can load and save in a few seconds and even can read (and write) several cassette formats. A basic CAS file will auto-run, I find that convenient, and Ascii based basic fille will not auto-run. You can also load and save with the menu on top of the window. But you could load a basic file in Ascii and save it to a CAS file. There are only a few settings, like selecting a machine and resetting a machine. Maybe in the future I will expand this a little, but never too much.

TRS80 emulator menu


Here you can download the latest version if this TRS80 emulator. This download is a zip file containing a portable x64 (and a x32 version) Windows exe programs, some directories with programs in .BAS and .CAS format. It us a portable program, just unpack it somewhere on the disk and start it by clicking it. This program is digitally signed with my own code certificate and it is trusted by Microsoft windows.

Download x64 (and x32) version 1.00 of hmp_trs80_emulator (2022)

  • Version 1.00
    • First (beta release) version, the program has been testen by myself on my hardware.

Links to information, documentation and tips

A very extensive description with schematics of the TRS80 Model I level II computer.
Sams ComputerFacts - Model I (1985)(Howard Sams)(pdf)

The well-known technical reference manual that Tandy sold and which was very poorly available.
Radio Shack TRS-80 Micro Computer Technical Reference Handbook 2nd

This is the technical reference manual of the TRS80 expansion interface.
Expansion Interface Service Manual (19xx)(Radio Shack)(pdf)

Wikipedia's page about the TRS80 model 1.
TRS80 wikipedia page

A very complete page with information about the TRS80 model 1.

Another very complete page with information about the TRS80 model 1

A nice page about bringing a TRS80 Model 1 computer back to life.

A site with a lot of information about all TRS80 computers (Ira Goldklang).
Ira Goldklang's TRS-80 Revived Site (Engels)

Last update: 21-08-2022

Disclaimer: All pages on this Web site are copyrighted by Hein Pragt, unless otherwise noted. I strive for accuracy but cannot be held responsible for any errors in the content. For questions about the content of this site or persmission to copy you can contact me at: (email: is registered under KvK number: 73839426.