Introduction - If you have any usage issues, please Google them yourself
The program features 8155 two 8-bit parallel output, six parallel port is used to read the keyboard state, microcontroller interval 0.5s read key 8155 6-bit parallel read an external keyboard, the analysis of the number of keys, two digital display the number of keys, the first format: ' 000, 111,222,333,444,555,666 '