实现单片机串口与3个RS232串口的分时复用，平时单片机串口一直在检测IC卡刷卡路串口，实现了多通道切换-MCU with three serial RS232 serial port interleaving, peacetime MCU has been detected in IC card for Serial, achieving multi-channel switch

基于单片机的交织编码器，采用汇编语言编写，用D触发器产生m序列。-Encoder based on single chip interleaving, using assembly language, using D flip-flop produces m sequence.