Category: Algorithms and Processing

Wrote Floating Point Math Package for MC6800

With the ongoing development of the Conviron CMP3000 environmental control system, Vansco needed someone to develop software.  I stepped up and was asked to develop a floating point math package to support the control algorithms.  It worked!  With minor bug fixes, it was in service for the next 15+ years.

At that time, the development system was the huge and heavy Motorola Exorciser II, which Vansco had bought surplus when Interdiscom had shut down.  The Exorciser was a card-cage based system, similar to an S-100 bus system (but not the same), which was comprised of the huge main chassis, a huge, solid and heavy dual 8 inch floppy drive chassis, and an ExorTerm display.

The display could only show upppercase characters.  The operating system was MDOS 3.11, a Motorola-specific O/S.  Editing was done in a line editor called EDLIN, or, if you happened to have a lot of time, a full screen editor called EDIT.  Argh, the system was slow!  Programming was performed in MC6800 macro assembly language, RASM, and in MPL, a PL/I-like high level language that very few have heard of.

Debug prototypes of Enercorp AI-1 Air Infiltrometer

The IAMC (Industrial Applications of Microelectronics Centre) had developed a product called the Air Infiltrometer 1 for Enercorp.  The AI-1 could automatically measure the leakage of a home by replacing one of the doors with a large fan, and measuring the pressure drop across it as the fan was sped up.  Enercorp had been manufacturing manual units that used TI-59 calculators, but the AI-1 made it all automatic.

The AI-1 mechanicals and PCBs were developed by Vansco.  The main board was based on the Motorola MC6802.  The PCBs came back and were built up, but everyone else was busy working on getting the Conviron CMP3000 going, so there was nobody to do the initial debug.

Although at that point, I had no idea what a microprocessor was or how it worked, I was given the MC6800 manual and Ed’s dusty old Krause Industries Micro Maniac development system, and asked to give it a go.  I put the development system together, dusted off the tape recorder, loaded up the development tape, and got the AI-1 up and running in 2 days.