Microcontroller Programming

Dar Scott provides programming services for embedded computers and microcontrollers.

Background

Over the years Dar Scott has written embedded applications for 68HC11, 8051, Z-80, 8080, '86, '186, '286, 6502 (including Triscend E5 CSoC), 6800, 6809, 68000 and 4040 microprocessors. For much of these part or all of the code was written in assembly language (or FORTH and assembler). In recent years most of the code has been written in C and assembler. In addition, as part of the software development, Dar Scott has programmed the surrounding logic using FPLA and CSoC technologies.

Dar Scott has written I/O code for serial port controllers, floating point modules, clock/calendar chips, D/A & A/D modules, IEEE-488 controllers (GPIB), parallel I/O boards, video boards, motor controllers, relays, power supplies, multiproccessor communications, tcp/ip drivers, STD boards, PC104 boards, optical sensors, timer boards, switches, scatter sensors, scanners, SPI bus, multiplexors, plotters, CCD arrays, tape drives, temperature sensors, thermocouples, current probes, telephone interfaces, telemetry devices and special memory devices.

Dar Scott has written applications for a variety of scientific and technical needs. These involve wavemeters, spectrometers, laser controllers, dye laser controllers, display controllers, microdensitometer controllers, welling logging instruments, telephones, laser environment monitors, monochrometers, photomultipliers, power-line loggers, power-line status units, microscopes, large electric motors, gas leak detection, X-Y tables, power supplies. These were for these industries: mining, power, defense, medical, semiconductor, optical, automotive, entertainment, physical security and standards.

Selected Microcontroller Projects

MS DOS File driver. For J&M Systems, Dar Scott wrote the 68HC11 code to write a simplified DOS file structure on floppy disks for data logging. If the user tried to boot from the floppy he got a message that said it was not a bootable disk and provided information on the floppy contents.

Monochrometer Controller. For an instrument manufacturer, Dar Scott designed the software for a controller in a monochrometer. The system featured enhanced communications and computer control capability, special commands for manufacturing and calibration, and advanced stepper motor slewing functions. This required intimate knowledge of the mechanical systems, the electronic systems and the physics of the product. This project involved C coding, assembler coding (68HC11), project management & supervision, software design and review of electronics design.

This project's stepper motor control software used Dar Scott's variation on microstepping that he calls fractional stepping. This method updates motor currents at steady time units rather than the traditional steady distance units. This allows precision control at low speeds and allows the achieving of high speeds. This method can be used to eliminate belts and gears in some applications.

Three Phase Fault Generator. Dar Scott designed and created a three phase fault generator used for testing fault-logging and fault-handling equipment. Care was required for accurate frequency and phase representation.

Pulse Wavemeter. For Sandia National Laboratories, Dar Scott developed the software and detailed analysis methods for a Z-80 based instrument for measuring the wavelength of short monochromatic pulses. He ported much of this code to 68000 for Lasertechnics, an instrument manufacturer who obtained the license for manufacturing the instrument.

Three Phase Analyzing Logger. For J&M Systems, Dar Scott developed an instrument used in the power industry. This involved multiple processor cards and I/O boards on the same SPI bus. Interboard communications is fast and reliable. Special considerations involved maintaining sustained accurate measurement periods while making in-depth calculations and logging to floppies.

High Power Laser Control. For Electro-Optical Systems, Dar Scott wrote software and selected I/O electronics for one controller and part of another for a high-power YAG laser. Hardware included 8051 processor boards, custom timing test boards, parallel I/O boards, GPIB boards, RS-485 boards and thermocouple boards.

Telemetry Interface. For Modular Integrated Technologies, Dar Scott wrote the software and programmed the surrounding logic for a telemetry interface with precision timing requirements. The unit interfaced with the computer via RS-232. All connectors had status indicators and the system provided a wide range of diagnostics features.

Lab

Dar Scott has an extensive electronics lab for supporting microcontroller and embedded computer projects with particular I/O needs.