串行口扩展并行口实验,使用P1.0、P1.1作为74164串行输入数据线和时钟线，74164的输出接数码管的段码，P1.2接一位数码管的位选码，在一位数码管上轮流显示数字（0～F）。-Parallel port serial port expansion experiments, P1.0, P1.1 as 74164 serial input data and clock lines, connect the digital output of the segment code 74164, P1.2 bit by bit digital election code, turns display digital (0 ~ F) on a digital control.