Modified 2006-04-19 10:39

REX 6000

I own a REX 6000 "microPDA", which I think is quite nice. It's small, it's cheap (795 Skr) and it has fairly good battery life - measured in weeks or months. It also has a 8-bit Z80 CPU which makes it slow and very, very cool.

I've done some programming for the REX, which is OK if you can live with buggy compilers, slow windows-based emulators and scarce resources.

My REX projects so far are:

REX Tafl	REX Tafl is a board game for the REX 6000. Tafl-type games are chess-like games and were played in northern europe during the middle ages.
REX Adventure	An adventure-game library. It provides library functions for simple implementation of Zelda/Monkey island-style adventure games. An example game is also included.
REX Arkanoid	Arkanoid is a breakout/arkanoid-style smash-the-bricks game.
Utilities	I have also written a few utilities for REX development. These include an image-converter, a REX image viewer and a memo-writer (useful in the emulator).

All projects are available in a subversion repository at https://mondragon.tek.bth.se/svn/main/world/ska/rex/.

Postcard

My REX-work are released under the GPL and therefore not Cardware. However, I like the Cardware concept, so if you like any of the things here you're encouraged to send a postcard of your hometown to me. The address is:

Simon Kågström
Östra Prinsgatan 18
371 31 Karlskrona
Sweden

Using the REX 6000 with Linux

First, a word of warning: I've tried the addin writer in rextools for Linux (for updating the Arkanoid game). It did not work, and also messed up my firmware a bit. The REX still works, but some things (like the world clock) display incorrectly.

Developing for the REX 6000 on Linux

I've done my REX development on Linux using the latest z88dk from cvs. I've had a few problems, namely:

In z88dk, you have to rebuild the REX c-library manually, by entering {z88dk}/libsrc and running make rex_clib.lib and finally copying that to {z88dk}/lib/clibs/
If you get errors such as:
```
	  1 errors occurred during assembly
	  Errors in source file hello.c:
	  File '/tmp/fileDIzIXx.opt', Module 'HELLO', at line 13, File open/read error
	
```
During assembly, see to it that the environment variable Z80_OZFILES is set to {z88dk}/lib/ (WITH the trailing slash - VERY important).
(This is mostly stupidity, but...): When you run zcc with -create-app, DON'T name the outputfile (-o ...) something.rex. This will cause garble it. Instead, use zcc +rex -create-app -o something.bin a.c, which will create something.rex.
A more general REX-programming problem: Be careful about types. I tried to access the memo database with a 32 bit integer (long) as file handle, whereas the REX really uses a 16 bit integer (int). Bad idea - the REX crashed to the point where it needed a reset. Be careful!
Another general problem: For addin-development, you only have access to 8Kb code size, so try to be conservative with the code (i.e. write short and effective code!). 8Kb does make the programming much more fun though!

There are two more things which you will find troublesome. First, you cannot upload your creations to your REX from Linux directly, especially not if you have the USB cradle such as me. Further, the REX/DS2 emulator does not run in Wine (it starts but hangs almost straight away).

The solution to the first problem is to: 1) Write a driver for the USB cradle (this has been done now!) and use Marek's REX tools (but these do not work incredibly well, unfortunately). Or, 2) Find a windows box and use that one.

The second problem is nastier. You could of course use the solution nr 2 above, but I'd say its too time consuming. What I did in the Arkanoid game was to separate the target-specific and generic code and write two target-specific frontends (one for the REX, naturally, and one for libSDL).

Z80 Reference card

I have recently reformatted a Z80 reference card by Magnus Hagander (mha@ticalc.org) in LaTeX. This is available in source and .PDF here:

z80ref.tex (14 KB)

z80ref.pdf (71 KB)

To contact me, mail to the following address (decrypted):

ska[at]bth[dot]se

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