what is the use of delimiters in Control Area Network (CAN)

[nareshgtr]

In the CAN there are two delimiters (ACK and CRC). Please can any body explains the what are uses of delimiters in the CAN.
Regards
V. Naresh Kumar

 

[microKernel]

Re: what is the use of delimiters in Control Area Network (C

ACK:
CAN is a multimaster bus protocol and each and every message is broadcast over the bus. If there is a receiver for the message, only that will ACK the messagee (at time of ACK bit), otherwise the sender will know that its message was not received by any node.

CRC
CRC is the checksum for the CAN message to make sure that the bits are propagated properly on the bus and received correctly on the receiver end.

 

[nareshgtr]

Re: what is the use of delimiters in Control Area Network (C

thanks for your reply microkernal
There is acknowledgment slot to ack the receiver. With the addition to this ack slot there is another slot is there i.e. ACKDELIMITER. I want know what is use of ACKDELIMITER.
Regards
V. Naresh Kumar

 

[microKernel]

Re: what is the use of delimiters in Control Area Network (C

I believe this is required due to NRZ coding (combined with no bit stuffing) used for CAN.

All other fields in CAN follow the bit stuffing rule (based on 5 consecutive bits of same level).

The fileds that are fixed in length with no bit stuffing have delimiters.
Some other frame types (Besides data & RTR) in CAN that have fixed bits also have delimiters.