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South West Technical Products Corporation

The SWTPC 6800 was the first computer system made by The SouthWest Technical Products Corporation and the first based on the Motorola 6800 microprocessor. Before manufacturing computers, SWTPC sold home audio kits and a kind of computer terminal called "Television Typewriter".

The SWPTC 6800 was introduced in 1975. The first system included a case with power supply housing a SS-50 and SS-30 bus based motherboard, a 6800 CPU card, a 2 KB. static RAM card and a serial I/O card. User had to buy an additional terminal to enter information, and thus a ROM monitor allowed him to examine and modify memory, load/save programs on tape or boot from a floppy disc unit.

Every original card was built around the Motorola family chips which made the SWTPC 6800 an inexpensive system for the time. The system was sold in a 2 KB kit version ($395) or 4 KB, 8 KB or 40 KB assembled versions. It came with a complete documentation including the 6800 programming manual and a program examples book.

The ROM and RAM was organized as follow: The MikBug chip (instant-on ROM BIOS) was 1024 bytes, of which 512 bytes were useable; MikBug let you write programs immediately in hex. The CPU board had a 2K bit RAM chip on it organized as 256 Bytes. The memory board included with the kit was 4K but it came with only 2K of RAM chips, 16 X 1024 bit.

Thanks to Michael Holley's SWTPC 6800/6809 documentation collection for some informations and pictures.

Dave O'Neil reports:
Loved seeing the old 6800 on your site. I am a high school physics teacher (I just retired). I built one in early '76 and two of my students went on to build one, too! At least 5 were immediately guided into computers when they saw it that year. I sent a passle of my BASIC physics programs to Wayne Green at Microcomputing and he published them in the June '80 issue of Microcomputing, p. 138.
There were a few newsletters printed and sent out free with all sorts of great stuff to input. Everyone grabbed the hex-binary one for finding bad memory chips. There soon was an assembler that everyone started writing programs with. Then a co-resident assembler/desembler. When Uiterwyck's 4K BASIC came out everyone, went to 8K or 12K. When his 8K came out, we went from 8K to 12K or 16K. I tell people that if IBM had gone Motorola instead of Intel, he'd be the richest man, now.

Chip Gill replies:
I am one of Dave O'Neil's students that also built this machine. Loved using it through 2 years of high school and 4 years of college. My college senior project was a 32K byte memory card for this system which replaced the 4 cards that were 4K each. Thank you very much Mr O'Neil for the inspiration and understanding of computers that I've enjoyed for over 30 years now.

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I first came across a SWTP 6800 when my Uncle (who ran a building firm) decided to buy one to "to the accounting and payroll". They quickly figured out they needed someone who could "drive" a computer. As they knew I had a Sinclair ZX81, at 17 I was introduced to this SWTP - the heart of a specifically written (in Basic) builders payroll and accounting system - named "FBS" (Franklin Builders System). The main system unit had an external disk enclosure (2 x 8" floppy disks), a Terminal with keyboard and finally an Epson MX80 dot matrix tractor printer. I was quickly able to use this SWTP for the payroll (70+ employees) and as a result, two part time clerks were let go, as their roles were consumed by the SWTP! (A harbinger of things to come?). I was running most office functions on this PC, payroll, job costing, orders, accounts payable, balance sheet, other ledgers. All on a single 8" floppy disk! I started writing programs (in BASIC) of my own, one was to automatically "pay" invoices when a cheque was entered. The original program laboriously presented you with one invoice after another and asked "would you like to pay this"? I even managed to used Basic commands to invent a new "graphical" character set to make the menus bigger and more interesting. You could see each character being quickly drawn! Ah, Happy days.

Monday 15th June 2020
Joe Mc (UK)

While in medical school in 1978, I bought and built a SWTPC 6800, with CPU, SS-50 bus, and 4k static ram card. Couldn''t afford an ASCII kbd ($$300!) and had no display - so a friend retrieved a Burroughs 32 character Plasma display (Ascii parallel interface) and a kbd removed from a pulp and paper mill - but it had 5-bit Hollerith-encoded outputs. Rewrote the monitor in EPROM to do the kbd code translation to ascii, and to make display on the 32 character display work. Later added a custom board to do file read/write to tape, based on software that directly drove an op amp connected to the audio-in of a stereo cassette deck. Had to add a 1 MHz crystal to the board (replaced the RC circuit) - Then added a board that mapped memory to an 80 x 24 character monochrome video display, and a massive 16kb dynamic memory board. Then with tiny basic (3.95kb), was able to program to heart''s content. It played star trek too.

Friday 13rd July 2018
Geoff Rutledge (California)

I worked with a brilliant engineer named Charlie Moore at a GM plant doing manufacturing R$D. When micros came out we wanted to experiment with one to see how it worked. Our IT people had to approved any computer purchase. They refused, claiming any micro was a toy and unusable in business. We called SWTP and told them our purchasing dept was sending them a RFQ for a "machine controller". They were to quote $395 and when a purchase order came in, ship the 6800 Kit always calling it a "machine controller" in all correspondence. We hooked it to an old ASR-33 teletype machine and later a tape recorder (Kansas City Std) By the time IT found out we had it, we were building a 16 channel high speed data acquisition system for our Detroit Diesel Test Dept for $71K that DEC could not touch for under $500K. Charlie wrote software and I designed hardware. Charlie was using an assembler he bought from a tiny startup named "Microsoft". Several times I answered the phone and the voice at the end asked, " Is Charlie Moore there? This is Bill Gates."

Wednesday 15th November 2017
David Monnier (Indianapolis, In)


NAME  6800
MANUFACTURER  South West Technical Products Corporation
TYPE  Professional Computer
YEAR  1975
KEYBOARD  Optional terminal
CPU  Motorola 6800
SPEED  980 Khz.
RAM  4 KB min., depending on models
COLORS  Unknown
SOUND  Unknown
SIZE / WEIGHT  Unknown
I/O PORTS  Serial
OS  ROM Monitor
POWER SUPPLY  Integrated P.S.U.
PERIPHERALS  S-50 and S-30 bus cards
PRICE  $395 (Basic kit version)

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