Introduction - If you have any usage issues, please Google them yourself
Stopwatch/Clock timer AT89C52 single-chip design, the smallest of the application of design the use of a total of Seven-Segment LED display Yang, P0 paragraph code output data, P2.0-P2.5 I make out scanning output, P1.0, P1.1, P1.2 I take three buttons switch to tune and when the feature set. In order to provide a total of Yang LED digital tube of driving voltage, using 8550 as the power transistor output driver.