Talking to the Hardware

Starting up a program can be a time of indecision. New tools offer the possibility of a better way. Microchip has the REAL ICE emulator and the MPASMX. I wanted to use as much of my preexisting software technology developed for Version 2. Could I easily migrate it from MPLAB8 and Emulator ICD3 to the new development tools? The new tools assume you are to develop using relative addressing and writing in C. Me? I am stuck in assembly language for this legacy project. I went down that road awhile seeing if the existing project could be morphed with little consequence and came to the conclusion it is better to stick with my current way of doing things and let a new project blaze that trail. I will have that opportunity with the PIC24 and the graphic terminal.

The MPU processor is different than the V2 predecessor so a lot of time and effort went into getting the initialization of the part and pins correct. That is behind me now and I started writing some application code. My concentration is on the amp board control signals to two A/D converters and one D/A converter. They all need drivers written and debugged. Also a 16–bit serial to parallel I/O port that controls relays and other controls.


Here you see the Microchip MPLAB ICD3 Debugger attached to the MPU board. The DigiView Digital Logic Analyzer is attached through clip on probes to the A/D converter circuit used to measure current. I am seeing the driver program being captured on the logic analyzer. It is a great tool. I connected a binary voltage source (designed in the 70’s and I still have one on the shelf) to the A/D input direct so I could confirm normal part operation. That all looks good and I can follow the bits. To confirm current measurement on the amp board, I substituted a 10 ohm sense resistor instead of the designed 0.01 ohm so that a mA through the sense resistor is equivalent to amps for testing purposes. The circuit measures the current drop and creates a ranged voltage output that can be measured by the A/D. I have concluded that I have the +/–  pins of the opamp reversed so I am going to have some minor surgery to correct that. Oops!

I have been dealing for weeks with an Italian company that is providing a screen graphics development tool for the LCD screen. It is much better than the Microchip solution. Evidently I am an early user and I am having to work with him to clear some bugs. I think that particular roadblock has now been cleared.

I look forward to an improving economy in 2012. Thank you for your support!

73 K5OOR –  Virgil





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