Introduction - If you have any usage issues, please Google them yourself
The keyboard is used non-coding MCS-51 microcontroller internal timer/counter, interrupt system and the external buttons and LED digital display and other components, to design a single chip non-coding matrix keyboard. And pass the key to achieve display 0,1,2,3,4,5,6,7,8,9, A, B, C, D, E, F.