The complex program control system

The complex program control system with multi switch input needs to be good at dealing with the standard single-chip microcomputer with multi switch input, rather than the small single-chip microcomputer with simplified I / O port and program memory, without selecting D / A and a / D functions. According to the above analysis, this design chooses p89c51ra as the main control device. 51 single chip microcomputer has powerful bit operation instruction, I / O port can be addressed by bit, program space can reach 8K, which is enough to meet the design. Moreover, 51 MCU is very cheap.