PPMScope
Microcontroller based PC Oscilloscope
...The bandwidth is lower than a commercial scope, so it's use is limited
to signals of 500 kHz and below. It's sample buffer is also smaller than
a commercial scope, however sufficient for most oscilloscope functions.
This is a version based on the PIC16F877A microcontroller running with a 20MHz
clock. The maximum sampling rate is 1 MHz with a 5 Mhz equivalent sampling
mode. Currently, the computer interface supports USB, serial, and parallel ports.
Good luck on the construction and I hope you enjoy your oscilloscope. I am
happy to answer any questions or provide technical support for this design.