11.2.5 CAN Test Modes
Using the Command Register loopback and the listen-only settings, the CAN controller performs certain test operations as summarized in the following table.
| Loop back | Listen-only | Comment |
|---|---|---|
| 0 | 0 | Normal operation |
| 0 | 1 | Listen-only mode The CAN controller receives all bus traffic but does not send any information to the bus. This feature is useful for automatic bit-rate detection. |
| 1 | 1 | Internal loop back The CAN controller receives the sending data. No data is sent to the network and no data is received. |
| 1 | 0 | External loop back The CAN controller participates in the regular CAN transmission and reception. Furthermore, a copy of all sent messages is received. This mode works only if at least one additional CAN node is on the network. |