用89C51串行口外接CD4094移位寄存器扩展8位并行口，8位并行口的每位都接一个发光二极管，要求发光二极管从左到右以一定延迟轮流显示，并不断循环。-Using 89C51 external serial port expansion CD4094 shift register 8-bit parallel port, 8-bit parallel port of each one, all light-emitting diodes, light emitting diodes require a certain delay in rotation from left to right shows, and continue the cycle.