**NEW** TRS-80 Model 4/4P I/O Interfacing

A summary of I/O Ports and bit definitions for Serial and Printer Ports.
Click here for Model 4/4P I/O Interfacing

19200-baud Serial Boot Loader for TRS-80 Models 3/4/4P

for PC host:
SBOOT4 v1.0 -- Serial Boot Loader for TRS-80 Model 4P
Copyright (C) 1999, Douglas Beattie Jr.

for PC host:
sBoot4T v1.1 -- 19200-baud Serial Boot Loader
(with Terminal Mode) for TRS-80 Models 1/3/4/4P
Copyright (C) 2000, Douglas Beattie Jr.

for TRS-80 targets:
Originally for the Model 4P only, the above DOS utilities can be used in conjunction with the /CMD Serial Boot programs, SBOOTX.ZIP (8K) which run on any TRS-80 Model 3 or Model 4 disk system (and I assume a Model 1 also, but I haven't verified this.) You can use David Keil's emulator to put the appropriate standalone serial boot /CMD program onto a TRS-80 floppy disk.

Here are some Notes about Model 4P Serial Boot

Attention Z80 Programmers!

You can cross-develop TRS-80 applications (or standalone Z80 apps too) from your PC, using the utilities above. To save them as a /CMD file, cross assemble without an argument to the END statement, upload the program, reboot the TRS-80, and use the DUMP command from TRSDOS to create an executable. (This is how I created the /CMD version of MEMSPY (see below).

Z80 FORTH System with source code

See the TRS-80 CamelForth Page

My own Z80 Programs with Z80 Source Code

ALSO: here's a nifty program to upload into your TRS-80 Model 3/4/4P: LORES03A.ZIP (5K) uses Mode 1 interrupts and demonstrates animated low-resolution graphics. Z80 Source code is included. Assembler used is the Zilog Macro Cross Assembler (640K DOS Version).

Also: MOD3G.ZIP (6K) is a modular version of the above. This package of Z80 source code will demonstrate the use of modules and linking with the Zilog Macro Assembler.

And a package for TRSDOS/LS-DOS, same as above, assembles with EDAS: LS-LORES.ZIP (17K)

NEW: MOD3G, modified to build using ZDS (Zilog Developer Studio) under Windows.  Also includes 4_MHz speedup, and different pattern speed:  MOD3GZDS.zip (7K)

MEMSPY -- Memory Spy

Here's a utility to examine memory, as after a program crash, or unusual system behavior such as lock-up. For the TRS-80 Models 3, 4, and 4P, it can also look into banked memory on a 128K system. Z80 source code is included  Download MEMSPY.ZIP (19K) and check it out.