单片机89S51控制6个数码管显示时，分，秒。其中，位码通过P0口的P0^0-P0^5 控制，段码通过74LS164的串入并出的移位寄存器来送出。-6 MCU 89S51 control digital display hours, minutes and seconds. Among them, the bit code through the P0 port P0 ^ 0-P0 ^ 5 control, the string section of code into and through the 74LS164 shift register to send out.