CAN 接收器总共有 5 级接收 FIFO，在接收过程中，收到的报文将会依次在 5
级的输入 FIFO　中进行保存。CAN 中，5　个报文缓冲器在工作过程中通过转换被
交替映射到单片机的每个存储器区域内。RxBG（后台接收缓冲器）只与　MSCAN
相联系，前景接收缓冲器能够通过 CPU 寻址。(The CAN receiver has a total of 5 stages to receive the FIFO, and in the reception process, the received messages will be in 5
Save in level input FIFO. In CAN, 5 message buffers are passed through conversion during work
Alternately mapped to each memory area of the microcontroller. RxBG (background receive buffer) only with MSCAN
Associated, the foreground receive buffer can be addressed via the CPU.)