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Using the PIC18F2550 GLCD Text Test as a basis for further experimentation, I put together a simple and accurate graphical oscilloscope using a PIC18F2550 microcontroller and a AGM1264F graphical LCD. The oscilloscope measures the average voltage, the maximum voltage, the minimum voltage, the peak-to-peak voltage, and the zero-crossing frequency for a DC signal over 100 samples. The oscilloscope has a built in edge trigger function that can be set to capture on rise or fall (or disabled altogether). The time scale for the display is variable and can be easily redefined using the changeTimeDivision function. Likewise, the voltage range can be change to 0-5V, 0-2.5V, and 0-1.25V. The main limitations of this oscilloscope include relatively slow acquisition time and sampling rate (~60kHz) and the fact that the inputs are limited by the constraints of the internal ADC. However, it is a very nice display and I highly suggest you view the videos to see it in action. Read more…

After working with HD44780 displays for such a long time, I’ve decided to try my hand at graphical LCDs. They are cheap and effective at displaying more information than character LCDs, and in a much more concise manner. Most controllerless graphical LCDs can be difficult to work with, however the KS0107/KS0108 controller combination allow for quick and easy programming. For this project, I opted to use the AZ Displays AGM1264F 128 x 64 pixel graphical LCD with the KS0108 controller. This circuit is a very simple proof-of-concept that has acted as a stepping stone for further development into more complex programs and displays. When constructed and run, the display will show the complete custom 3×5 character set that I put together for the firmware (using the font format from Cornell University and additional font information from Michael Koss). Read more…

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