Snoop mode is used for test and debug. When in snoop mode, the controller must only be programmed to enter configuration mode or be held in reset. In snoop mode, these actions occur:
- Controller transmits a recessive bitstream onto the CAN bus
- Controller does not participate in normal bus communication
- Controller receives messages that are transmitted by other CAN nodes but does not ACK
- RX messages are stored based on acceptance filtering
- Software can program acceptance filters to dynamically enable/disable and change criteria
- Error counters are disabled and cleared to 0; reads to error counter registers return to 0
Recommended: Xilinx recommends that snoop mode be programmed only after system or software reset.