CP500: A Brazilian TRS-80 Clone

This page is dedicated to the CP500, a Brazilian computer manufactured by Prologica during the 1980's. Here you will find most of the information required to revive a realistic experience with that computer and also to get in touch with other people who share the same interests. Everything has been gathered in a single page to make your reading brief and pleasant.

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The CP500 is 100% compatible with the TRS-80, which means that all software developed for the American machine runs perfectly in the Brazilian one and vice-versa (there are a few exceptions, though).

There is a significant community of TRS-80 fans in the US and around the world. Thanks to those people, we have access to software that allow us to emulate the TRS-80 in modern computers. In addition, hundreds of TRS-80 floppy disks are available around the Internet in virtual form -- as files -- and the programs stored in them run exactly like they would in a real computer. Some emulators are so impressive that even disk drive noises are reproduced, making you feel like you are in front of a legit vintage machine!

Only four CP500 models were produced, but a much larger number of TRS-80 models existed. There were the TRS-80 models I, II, III, 4, the laptop versions 100, 102, 200, 600, the MC-10, eight different versions of Pocket Computers, not to mention the international clones among which the CP500 is just one of them. Not all of these models are compatible with each other. The table below shows the four CP500 models ever created and their relationship to the American TRS-80 models.

Model Year CPU ROM RAM Text Graphics Compatibility
CP500 1982 Z80 2MHz 16KB 48KB 64x16, 32x16 128x48 TRS-80 Model I/III
CP500 M80 1985 Z80 2MHz 16KB or 2KB* 48KB or 64KB* 64x16, 32x16, 80x24 128x48 TRS-80 Model I/III/4
CP500 M80C 1986 Z80 2MHz 16KB or 2KB* 48KB or 64KB* 64x16, 32x16, 80x24 128x48 TRS-80 Model I/III/4
CP500 Turbo 1987 Z80 4MHz 16KB or 2KB* 48KB or 64KB* 64x16, 32x16, 80x24 128x48 TRS-80 Model I/III/4

*The CP500 M80 and the models produced after that were equipped with a board that enabled them to run the CP/M operating system. The CP/M leaves 64KB of RAM available to the system and reduces the ROM addressing to only 2KB.

To actually see how this beauty worked, here is a list of everything you are going to need:

  • A TRS-80 emulator compatible with your operating system
  • A file containing a TRS-80's ROM image to use in the emulator
  • A file containing a floppy image of a TRS-80 compatible operating system
  • More floppy images containing games, applications, utilities etc.
  • Operation manuals

Don't worry, I've got all you need in the following sections. You can also stop by my Favorites page and check out the nice list of links I've put together to other TRS-80 pages around the world. When you feel like it, please come get in touch with other TRS-80 fans in some of the Discussion Groups listed by the end of that page.

Emulators

Let me suggest you some of the best TRS-80 emulators I am aware of:

Emulator Author OS Description
TRS32 Matthew Reed Windows This program emulates the TRS-80 Model I, III, 4, and 4P. The CPU emulation is extremely accurate, supports all known instructions, and runs at exact TRS-80 speed. It is also extremely fast, being written in assembly language, and can exceed actual TRS-80 speed on any computer capable of running Windows. The floppy disk emulation is incredibly accurate and will even work great with self-booting or protected disks, such as Super Utility.
xtrs Tim Mann Unix xtrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Unix and the X Window System. It includes lower case, the real time clock, hi-res graphics, serial port, parallel printer, mouse, cassette, sound and music output (requires OSS), 5" and 8" floppy disk drives in single and double density, and even hard disk drives.
SDLTRS Mark Grebe Mac OS sdltrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Macintosh OSX, Windows, and Linux. It has been ported from Tim Mann's excellent X-Windows UNIX emulator xtrs. Instead of using the X-Window system for graphics, it uses the portable SDL library.
TRSEMU Peter Phillips WWW This web page emulates a TRS-80 Model III using only Javascript. This emulator is really a testament to the extreme speed of modern computers and the astounding new Javascript interpreters. The combination can easily emulate the function of the TRS-80 running at 2MHz. That's well over 100,000 emulated instructions per second!
Others Others Others If you need an emulator for other operating systems, I suggest that you research the trs-80.com website. Ira Goldklang maintains a list of all known emulators along with the links for downloading them.

ROM Images

Thanks to the Prof. Gustavo E. A. P. A. Batista, the CP500 community had access to the first image of a CP500 ROM extracted directly from the computer chips with an EPROM reader. The CP500 ROM has 16KB unlike the 14 KB found in the TRS-80. According to an analysis made by Matthew Reed, these 2KB extra contains the Z80 resident monitor, which appears to be an exclusive feature of the CP500. A comparison between both ROMs also showed that only 90 bytes differ, mostly because of translated messages from English to Portuguese.

Because the Z80 monitor occupies a memory range conflicting with video and keyboard addresses of the original TRS-80, this feature does not work in the TRS32 emulator. For some unknown reason, to access the CP500 ROM (like when you turn on the computer without floppies in the drives) you must first boot the emulator with a DOS500 disk and then reboot it again without disks. Maybe there is something in the DOS code that "enables" the ROM.

If you are a happy owner of a CP500 and wishes to extract a ROM image by yourself, you can use the following code written in Disk BASIC:

10 OPEN "O",1,"CP500/ROM"
20 FOR X=0 TO &H37FF:PRINT#1,CHR$(PEEK(X));:NEXT X
30 CLOSE 1

In case you don't have a real machine to extract a ROM image, you can download it from here:

Operating Systems

In the 1980's the market wasn't dominated by a few operating systems, like it is nowadays. For the TRS-80 there was at least a dozen different OSes available for the users to choose. The links below allow you to download some of the main options in this category:

Software

It is amazing to see a computer equipped with only a 8-bit and 2MHz processor be capable of doing so many interesting things. Among the software available for the TRS-80 you will find:

  • Applications like text editors, spreadsheets and database management systems
  • Games and programs for creating graphics and sound
  • Compilers for many programming languages
  • Many utilities

Despite all this variety, there are a handful programs that, for one reason or another, really enchanted me when I was a teenager. If you don't mind, I would like to share some of these memories with you:

Operation Manuals

Two manuals were provided along with the CP500, one oriented to its operation and BASIC programming, and another one to the usage of the DOS500 operating system. There are also technical manuals for the hardware maintenance of the TRS-80, but I am not sure to which extent the hardware of the TRS-80 and of the CP500 are similar.

Some other books

There is also an assortment of other books published at the time, aiming to help users improve their skills at the computer. Some were intented to teach programming, and some others provided extra information on the use of operating systems. Below you see a few examples of such books:

Wrapping up

You now have everything you need to have your own TRS-80 at home: the emulator, the ROM image, the operating system and some software samples. The next step is to pay a visit to my Favorites page to check out dozens of links from where you can obtain more information, documents and software for your new vintage computer. Enjoy!