TRS-80 Tool

trs80-tool is a command-line tool for inspecting and manipulating TRS-80 files, cassettes, and floppies. Its source code is available on Github.

Table of contents


You can download stand-alone binaries of the latest version:

File formats

The trs80-tool program supports these file formats:

Basic program. It's typically tokenized (token words like PRINT are stored as a single byte), but the tool supports reading Basic programs that are in text (non-tokenized) format. When writing a file with a .BAS extension, the file is always tokenized.
Basic program, but always in text (non-tokenized) format. The extension is mostly useful when writing a Basic file, because it tells the converter to use the non-tokenized format.
A cassette's audio stream. It can be at any sampling rate, either 8 or 16 bits per sample, and either mono or stereo.
A cassette stored in a compact form where each bit on the cassette is stored as a bit in the file. It includes synchronization headers and bytes, as well as start bits (for high-speed cassettes). This is a decent archival format for cassettes.
A machine language program as stored on a floppy disk.
The same format as .CMD, but is meant to store system code in an disk operating system.
A machine language program as stored on a cassette. The name comes from "Model 3 BiNary". This is typically not used, and instead these files are stored within .CAS files.
A 250-baud file written by a Level 1 machine (Model 1 or 3). It can contain a system file or a Basic program.
A floppy disk format for the Model I. It's very simple, capturing the basic sector data. It does not capture enough information for copy-protected floppies. It's named after Jeff Vavasour.
A floppy disk format for the Model III. It's very simple, capturing the basic sector data and IDAM structure. It does not capture enough information for copy-protected floppies. It's slightly more capable than .JV1 because it can encode a mix of FM and MFM signals on the same track.
Another floppy disk format, capturing more information from the floppy, such as some bits between sectors. Named after David M. Keil.
Generic file extension for floppy disk—could be a .JV1, .JV3, or .DMK file. Use the info command to find out.
SuperCard Pro raw flux floppy disk format.
An assembly language file, generated by disassembling a .CMD, .SYS, or .3BN file using the disasm command.
An assembly language listing file, generated by the asm or disasm commands’ --listing flag.
A raw machine language file, often used as the contents of ROM.
A file of unknown type, but sometimes synonymous with .ROM.
Intel HEX file, a text file for burning EPROMs. Can be generated by the assembler when developing a ROM.


The tool takes a command as its first argument:

% trs80-tool COMMAND args ...

Global flags are:

--version         Show the tool's version number.
--help            Show the usage message.
--color=COLOR     Force color mode (off, 16, 256, 16m, or auto).

By default trs80-tool detects the color capabilities of the terminal and sets the --color flag automatically. You can override this, either to turn off color (if it bothers you) or to force it on (when piping into a pager). For example:

% trs80-tool --color=16 hexdump in.cmd | less
--trace=MODULE    show trace logs for module (base, emulator, floppy).

Show tracing logs for the specified module. These log lines can reveal how the module makes various decisions, and can help debugging. This flag is mostly intended for the developer, but can help explain why (for example) a specific floppy isn't being recognized. The “base” module deals with TRS-80 file formats; the “emulator” module is the TRS-80 emulator itself; and the “floppy” module is for floppy-related messages. Repeat the option to enable tracing for multiple modules.


The dir command shows the contents of an archive file. Archives files are those that can contain other files. These are cassette files (in WAV or CAS format) and floppy disks (in JV1, JV3, DMK, or SCP format).

% trs80-tool dir FILE

The output format depends on the type of archive. Cassette files show baud rates, whereas floppy disks show creation date and type of file.

Normally system file are hidden, but can be shown by specifying the --system option.


The info command takes a list of filenames and displays a one-line description of the contents of the file, such as its type (system program, Basic program) and, if known, the embedded filename.

% trs80-tool info in1.cmd in2.bas in3.cas in4.wav

The --verbose flag displays some information (like floppy geometry) for some file types:

% trs80-tool info --verbose in1.dmk in2.dsk


The convert command converts a list of input files to an output file or directory. There are several different ways to use this command.

A single file can be converted to another format:

% trs80-tool convert in.cmd out.3bn    (diskette to cassette format)
% trs80-tool convert in.bas out.asc    (de-tokenize Basic program)

Several files can be put into an archive:

% trs80-tool convert in1.bas in2.3bn in3.cmd out.wav

This creates a cassette audio file containing the three files. Note that the .CMD file will be converted to .3BN format.

Archive files can be extracted if the destination is a directory:

% mkdir out
% trs80-tool convert in.wav out    (decode cassette and extract files)
% trs80-tool convert in.cas out
% trs80-tool convert in.dmk out

Archive files can be converted to other archive formats:

% trs80-tool convert in.dmk out.wav
% trs80-tool convert in.wav out.cas

When writing a cassette format, the baud rate of the input file will be used, if it's known:

% trs80-tool convert in1.cas in2.cas in3.cas out.wav

(The baud rate can be guessed from the .CAS file contents.) If the baud rate can't be guessed, 500 baud (low-speed) will be used:

% trs80-tool convert in1.bas in2.3bn out.wav

This can be overwritten using the --baud command-line flag:

% trs80-tool convert --baud 1500 in1.cas in2.cas in3.cas out.wav
% trs80-tool convert --baud 1500 in1.bas in2.3bn out.wav

If a system program doesn't have a built-in start address, one will be guessed by the info command:

% trs80-tool info in.cas
in.cas: System program (VCEPRN, /17408) on a low speed cassette

The start address can be set with the --start flag:

% trs80-tool convert --start 17408 in.cas out.cas
Wrote out.cas: System program (VCEPRN) in low speed CAS file
% trs80-tool info out.cas
out.cas: System program (VCEPRN) on a low speed cassette

The address auto can be used to guess an appropriate start address:

% trs80-tool convert --start auto in.cas out.cas
Wrote out.cas: System program (VCEPRN) in low speed CAS file

When converting .BIN or .ROM files, the --start flag specifies both the load address and the start address:

% trs80-tool convert --start 0x1024 in.rom out.cmd

An assembly language listing disassembly file can be generated from .CMD, .SYS, and .3BN files:

% trs80-tool convert in.cmd out.asm
% trs80-tool convert in.3bn out.lst

The disassembler attempts to guess what is code and what is data. If the input program relocates itself, some entry points will be missing and code will instead be disassembled as data. You can explicitly list entry points:

% trs80-tool convert --entry 0x7059,0x7064,0x71B9,0x7263 in.cas out.lst

See also the disasm command.


The hexdump command displays a hex dump of the input file, with annotations. See the --color flag for how to force coloring on or off. By default the command will collapse consecutive identical lines:

% trs80-tool hexdump in.cmd

Use the --no-collapse flag to turn off this collapsing:

% trs80-tool hexdump --no-collapse in.cmd


The sectors command displays a table of the sectors in a floppy disk. The columns are the sectors and the rows are the tracks. For each sector a character is displayed:

- No sector.
S Single-density sector.
D Double-density sector.
X Deleted sector.
C CRC error (ID or data).

Use the --contents flag to also show the contents of the sectors.


The asm command assembles the specified assembly language source code:

% trs80-tool asm program.asm program.cmd

It can generate .CMD, .3BN, .CAS, .WAV, BIN, or HEX files. For .CAS or .WAV files the default baud rate is 500, but can be set with the --baud flag:

% trs80-tool asm --baud 1500 program.asm program.cas

A listing file can be generated with the --listing flag:

% trs80-tool asm --listing program.lst program.asm program.cmd


The disasm command disassembles the specified program:

% trs80-tool disasm saucer.cmd

If the program is a .CMD, .SYS, or .3BN file, it is loaded into the correct place in memory. If it's a .ROM or .BIN file, it is loaded at 0x0000, but this can be change with the --org flag:

% trs80-tool disasm --org 0x8000 file.bin

The disassembler tries to guess which bytes are code and which are data by following the path of the program, starting with its main entry point. Additional entry points can be specified with the --entry flag:

% trs80-tool disasm --entry 0x0000,0x3799,0x377B model3.rom

Note that if any entry point is listed, then 0x0000 must be specified again if applicable. The output can be controlled with --no-labels to not create labels for jump targets and --no-known to not reference known ROM addresses. The --hex-format flag controls the format of hex numbers, which can be c for 0x12 (the default), dollar for $12, or h for 12h.

A listing file can instead be generated with the --listing flag:

% trs80-tool disasm --listing program.cmd

The --no-binary flag will suppress opcode binary in the listing. The --upper flag will generate upper case assembly language.


Run a TRS-80 emulator in the shell:

% trs80-tool run

This is experimental and does not currently work well with games, and may not work at all in a Microsoft Windows shell.

Use the --model flag to specify the model (1, 3, or 4, defaults to 3) and the --level flag to specify the Basic level (1 or 2, defaults to 2).

% trs80-tool run --model 1 --level 1

Specify a program or floppy to load and run directly:

% trs80-tool run tdos13a.dsk
% trs80-tool run frogger.cmd

Use the --mount flag to specify a cassette or floppy to mount:

% trs80-tool run --mount in.cas

Only one cassette may be mounted, but several floppies can be specified and will be assigned to consecutive drives, starting at 0:

% trs80-tool run --mount in.cas in1.dmk in2.dmk in3.dmk

If, from within the emulator, you modify the floppy, the virtual file will be modified as well. Specify the --write-protected option to mount all floppies as write-protected.

The --xray flag shows nothing in the shell but starts a web server for the X-ray debugger. This is experimental and not yet documented.


Starts an interactive session for exploring the Z80. Type help to get a list of commands. Type an assembly language instruction (such as ld a,5) to assemble it, write it to memory, explain it, execute it, and show its effects on flags and registers. This virtual machine is not in a TRS-80 context (it has no ROM or peripherals).


The help command shows more specific information about other commands:

% trs80-tool help dir
% trs80-tool help convert


Change log

This change log covers the tool and the related web apps (My TRS-80, the IDE, and the cassette reader).

2.7.0 Apr 12, 2024

2.6.0 Dec 31, 2023

2.5.0 Oct 4, 2023