Rx72m的CAN通信 单板使用内部回环自测 报文不能接收

使用瑞萨的Rx72m，进行CAN通信，使用一个单板，进入内部回环自测，即设置api_status = R_CAN_PortSet(g_can_channel, CANPORT_TEST_1_INT_LOOPBACK);

然后报文可以发送，参考了官方的例程，但报文不能实现接收

/*** RECEIVED any frames? */
api_status = R_CAN_RxPoll(g_can_channel, CANBOX_RX);
if (api_status == R_CAN_OK)
{
nr_frames_rx++;                              //这里，数值没有任何的变化

/* Read CAN data and show. */
api_status = R_CAN_RxRead(g_can_channel, g_mb_mode, CANBOX_RX, &rx_dataframe);

/* You can set BP here and check the received data in debugger. */
R_BSP_NOP();

#if BSP_CFG_IO_LIB_ENABLE
printf("Received CAN ID 0x%X, nr_frames_rx = %d.\n", rx_dataframe.id, nr_frames_rx);
#endif
if (api_status == R_CAN_MSGLOST)
{
#if BSP_CFG_IO_LIB_ENABLE
printf( "MSGLOST\n");
#endif
R_BSP_NOP();
}
}