串口通信，实现波特率1200，收/发时钟频率与波特率之比为16，实现与PC机的通信。-Serial communication, to achieve baud rate 1200, T/R ratio of clock frequency and the baud rate of 16 to achieve the communication with the PC machine.

STC89C51RD单片机普通模拟IO串口-Generic software uart written in C, requiring a timer set to 3 times the baud rate, and two software read/write pins for the receive and transmit functions

使用单片机STC89C51RC普通IO口模拟串口三种方法-// 1. get_rx_pin_status() // Returns 0 or 1 dependent on whether the receive pin is high or low. // 2. set_tx_pin_high() // Sets the transmit pin to the high state. // 3. set_tx_pin_low() // Sets the transmit pi