This paper analyzes the realization principle of traditional parallel programming techniques,taking AT89S51 as the prototype,introduces the principle using serial peripheral interface(SPI)protocol to realize serial programming,and taking P89V51RD2 as the prototype,introduces the principle using universal asynchronous receiver/transmitter(UART)serial interface protocol to realize serial programming,compares two serial programming techniques,expatiates the user program protection and application method of sig...