Is This Australia's First PC? Part 4: Legacy and Reflections
The Lasting Impact of the TRS-80 and Dontronics
Updated 23-Dec-2025, 3:58 PM by Don McKenzie.Miscellaneous Items Excalibur 64 Maximite - Duinomite - and Geoff Graham - 2011 Simmstick Dontronics Shopping Cart Gendon PBUFF Agreement The Little "rAVeR!" Programmer
Miscellaneous Items: Don McKenzie and Dontronics Related
I did a Podcast with ACMS (Australian Computer Museum Society) when I was in Darwin in January 2024. Click on the button below to listen to it. Covers my First PC claim, Dontronics, PBUFF, George Julius - ATL Tote, and many other items.
ACMS PodcastI just had a quick look over David Jones EEVblog and found some mentions of Dontronics that may be of interest. It was not an extensive search. A couple of video clips, etc.
EEVblog - David Jones Video 1 ▶ EEVblog - David Jones Video 2 ▶ Closing Dontronics Dontronics customer feedback in October 2006
A link to the Narkive Newsgroup Archive. I had forgotten I did a 64K and a lower case mod for the Tandy COCO computer. Plus many other TRS-80 and System-80 items.
Narkive Newsgroup ArchiveExcalibur 64
After the TRS-80 days, we got involved in an Australian designed computer, the BGR "Excalibur 64", that was effectively a colour version (clone) of the TRS-80, and Mick became president of the new club we had formed. He designed the software and hardware for a high resolution graphics board, and a 512kb memory extension, mainly used as a ram drive for the Excalibur, and had many other designs, such as an internal-external 1200/75 baud modem. Other projects of his were printed in Electronic magazines.
The BGR Company was operational for only about 12 months, and the club survived about 3 or 4 years. At this point, IBM clones came along and swamped the market, and I think most of us sold our Excalibur 64s.
Here is the original sales brochure (1983):
Excalibur Brochure PDF My Excalibur Page
Maximite - Duinomite - and Geoff Graham - 2011
Our involvement extended to the Maximite project, which Geoff Graham had ingeniously crafted, blending MM-Basic software with hardware housed in a PIC chip. After my TRS-80 Basic experience, I was captivated with this innovation.
Later on Geoff wrote a version to run on the Duinomite. Thebackshed - Maximite
Maximite and The Dontronics "Arduino" Duinomite. Online screenshot from Silicon Chip edition Dec-2011 Page 61. Click on images to enlarge. You can actually see dontronics.com on the overlay of the images. This article was written by Geoff Graham.
My friend Mick Gulovsen and I came up with a new hardware design for Maximite, and it was produced with the assistance of Tsvetan Usunov and his team at Olimex in Bulgaria. Still being produced. Mick named it Duinomite, pronounced "Dynamite". I had forgotten how much work myself and Mick Gulovsen put into the Maximite-Duinomite hardware migration.
Olimex Duinomite Open-Source Hardware Olimex Product Listing Olimex DUINOMITE-MAXIMITE PDF Olimex Duinomite Users Manual PDF Olimex Duinomite MEGA Schematic PDFSimmStick
Antti Lukats from Estonia introduced the concept of microcontroller plug-in modules utilising the widely popular 30-pin Memory Module socket for PCs of that era. Our initial encounter likely transpired on the Piclist forum, igniting a strong friendship between us. While I admired his idea, it lacked essential components--no supporting modules, no power supply, essentially just a standalone small card. Antti had a problem delivering boards for me, so I had to go it alone if I wished to proceed.
Determined to enhance its potential, I embarked on designing my own "DT" support boards, fostering an open-source platform accessible to all. This decision catalysed an unprecedented global expansion, with enthusiasts worldwide eagerly joining the endeavour. I added AVR Micros to my list, and other designers added whatever they needed. As long as they run on the SimmStick 30-pin platform, and interface to all of the I/O boards.
Images below from Rob Severson USBmicro.com
A U401 attached to the rear of a DT003 main board:
A U401 in the SIMM socket of a DT003 using pins and a DT208 with a socket strip
Antti laid claim to producing the very first printed circuit board for an AVR micro when it was introduced. Yes, it was on a SimmStick.
We successfully sold over 50K SimmStick variants worldwide, with distributors established in numerous countries. Additionally, third-party entities had developed their own versions of the SimmStick platform. We even organized Dontronics design contests, awarding a $500USD prize in 1999 and $1000USD prize in 2000 to the winner. While some links on the provided URL may be unavailable now, it should still provide a good overview of the concept.
Simmstick SimmStick First Prize Award 1999 Dontronics SimmStick Listing Google SimmStick Images
What I really loved about the SimmStick from a sales point of view: We got hold of some rugged large brown envelopes, that Australia Post approved of for standard local and Airmail International postage rates. SimmStick measured 1" by 3.5" for the smallest board. I could use masking tape to paste a panel of 8 or 10 boards together, and pop them into a standard rate envelope for postage, so I was able to offer free postage for a minimum value ordered. If I lost the occasional one, I simply replaced it.
Actually the Wayback Machine is a great way of searching now non-existent pages on both Dontronics.com and Simmstick.com
Wayback Machine: Dontronics World Wide SimmStick Dealers Wayback Machine: SimmStick.com eBay: Dontronics EZ-USB DT203 DT204 Micro Controller Boards
Dontronics Shopping Cart
In 2011, I revamped my shopping cart for the third and final time. To temporarily run parallel carts, I acquired dontronics-shop.com. However, I eventually allowed the registration to lapse, along with the accompanying database. The Wayback Machine came to my rescue again. Fortunately, Wayback saved most pages.
Dontronics Shopping Cart 1999 Dontronics Shopping Cart 2005 Dontronics Shopping Cart 2012 Dontronics Shopping Cart 2016Below appears to be Volume One of my catalogue. Click on the image to download the PDF file.
eBay Gendon3
Not only was my product "name and EPROM" copied for this mod, they are still supplying it in the UK. Gendon3 Lowercase modification kit for the Tandy TRS-80 Model I vintage computer. NOTE: This was done by Ian Mavric, so I am fine with that.
eBay Gendon3 Lowercase Kit Listing
TRS-80's and System-80's had all upper case characters only. It appears this was done to save a single 2102 memory chip on the main board. After adding that chip, a suitable lower case character generator, supporting circuitry, plus a suitable video driver, lower case could be displayed.
I had "Don's Authorized Modifiers" Australia wide. We were the first to offer 3 line descenders. All of the others had the letters "y,j,g,p, and q" actually sitting above the base line. These were simply the contents of the original character generators being displayed.
The original character generators in these computers was mapped out 5 bits wide by 7 bits high. (8 bits high with a one line descender) By addressing the generator with an extra address and data line, I was able to map out 6 bits wide by 12 bits high, which is the full available space of one character. This allowed me to output 3 line descender characters.
Many U.S. companies produced kits with descenders after mine appeared, and later System-80's had 3 line descenders.
I found the back story on the eBay Gendon3: Gendon3 Back Story
PBUFF and Ectron Agreement
Updated 26-Apr-2024
You should be able to find fully commented PBUFF DRAM read-write routines, and the ASM files for up to 4Mb memory size. RW256.MAC, PBUF5P1S.Z8T. I have also loaded these files up to:
Don McKenzie Files 1978-1995 (4.8MB) ▼
All pre-Dontronics files, and if I find others, I will add them also.
The PBUFF - Ectron PTY LTD Agreement:
Nearly 40 years ago, I signed an agreement with this now defunct Australian company to create the software to upgrade their current 64K printer buffer to a 256K buffer. It allowed me to continue supplying my software in EPROMs as part of my printer buffer kit, which was aimed mainly at the computer hobbyist market. Click on image below to enlarge:
The Little "rAVeR!" Programmer. What a blast this was!!!
We sold thousands of these, and I had a good friend of Mick's and mine, Ray Osborne, assembling them for me.
The Newbies MicroController Starting point. Covers Hardware and Software from an entry point of view. Many "Older" Engineers may learn from this also. And this is more cost effective than anything else going today.
The DT006 board will program the popular AVR Micro 8, 20, and 28 pin DIP chips on board, and will also program the DT107, (8515 and 4433 footprint) DT104, (2313 footprint) and SIMM100 (8535 footprint) AVR SimmSticks, as well as any AVR target board that has a Kanda type header. Current burning software is achieved with the programmer software built into MCS Bascom-AVR, HPInfo Codevision C, and Imagecraft C.
The Little "rAVeR!" Programmer
31-Mar-2000 From B.T. Salt Ash NSW Australia. Hi Don, I got the AVR kits up and running in no time, the BASCOM compiler is a joy to use! (Unlike that pig of a thing I bought from Dick Smith)
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