Types of errors in CAN protocol


Bit Error:  Whenever a node transmitting the data it is also monitors the data until the receiver receives the data. It is expected that the data to be same until the receiver receives. For example if the node is transmitting 0(dominant) to the bus and it is detected 1(recessive) in the bus then it is bit error.
ACK Error: whenever the transmitting node doesn’t monitor the dominant bit in the ACK slot then it is ACK error.
Stuff Error: After 5 consecutive bits the 6th bit will be invert (opposite) of the 5th bit otherwise it will be Stuff Error.
Normally the data frame will be 108 bits for standard format and 108+18 for the extended format but the two standard and extended formats are varied (total bits in both formats) based on number of stuff bits inserted.
The stuff bits inserted because for the error detection. After 5 consecutive bits if we are inserting the 6th bit opposite to the 5th bit on edge is occurred the Resynchronization is possible.
The Resynchronization is for the error detection.
Synchronization: It is the co-ordination of events. 
CAN is based on NRZ signaling why because the bit time is constant for the 1 successful bit level.
In RZ signaling synchronization possible is very easy but CAN is chosen only NRZ. Because in CAN bit time calculation the entire bit time is constant for one bit level.
Form Error: In CAN formats the fixed formats bits are CRC Delimiter, ACK Delimiter and EOF these are fixed format fields always recessive for the resynchronization. If any of the bits are dominant then it is form error.

CRC Error: The result of the CRC calculation by transmitting side and receiving side is not same then it is CRC error. 

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