37.5.1.8.2 Internal Loop-Back Mode

Internal Loop-Back mode is entered by programming the TEST.LBCK bit (TEST <4>) and the CCCR.MON bit (CCCR <5>) to ‘1’. This mode can be used for a 'Hot Selftest', meaning the CAN can be tested without affecting a running CAN system connected to the CANx_TX and CANx_RX pins. In this mode the CANx_RX pin is disconnected from the CAN and the CANx_TX pin is held recessive. The following figure shows the connection of the CANx_TX and CANx_RX pins to the CAN in case of Internal Loop-Back mode.