测试CAN接口(sja1000) ,每接收到一帧数据,就 原样 回发 一帧!!!! (拨码开关全 拨到 ON ,上位机 发送帧 ID为 0)-CAN Test Interface (sja1000), each receive a data, on the back fat as a DIP switch !!!!( appropriated for the entire ON, host computer to send the fr a me ID of 0)