
CAN PROTOCOL
Rev. 3
MOTOROLA
iii
TABLE OF CONTENTS
Paragraph
Number
Page
Number
TABLE OF CONTENTS
5
FAULT CONFINEMENT
5.1
5.2
CAN node status ...................................................................................................5-1
Error counts...........................................................................................................5-1
6
BIT TIMING REQUIREMENTS
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.8.1
6.9
6.9.1
6.9.2
6.9.3
6.9.4
6.9.5
Nominal bit rate .....................................................................................................6-1
Nominal bit time.....................................................................................................6-1
SYNC_SEG...........................................................................................................6-2
PROP_SEG...........................................................................................................6-2
PHASE_SEG1, PHASE_SEG2.............................................................................6-2
Sample point..........................................................................................................6-2
Information processing time ..................................................................................6-2
Time quantum........................................................................................................6-2
Length of time segments .................................................................................6-3
Synchronization.....................................................................................................6-3
Hard synchronization.......................................................................................6-3
Resynchronization jump width.........................................................................6-3
Phase error of an edge....................................................................................6-4
Resynchronization ...........................................................................................6-4
Synchronization rules ......................................................................................6-4
7
INCREASING OSCILLATOR TOLERANCE
7.1
7.2
7.2.1
7.2.2
7.2.3
7.2.4
7.3
7.3.1
7.3.2
7.4
7.5
7.5.1
7.5.2
7.6
7.7
7.8
Protocol modifications ...........................................................................................7-1
Determination of the maximum synchronization length.........................................7-2
Local error, where at least two of the nodes are Error ACTIVE.......................7-2
Two consecutive Overload frames...................................................................7-3
Acknowledge error at transmitter, where all nodes are Error PASSIVE...........7-4
Local error at transmitter, where all nodes are Error PASSIVE........................7-5
Bit timing................................................................................................................7-6
Construction of the bit timing for maximum oscillator tolerance.......................7-6
Construction of the bit timing for maximum bit rate..........................................7-7
Calculation of the oscillator tolerance....................................................................7-8
Maximum oscillator tolerances..............................................................................7-9
Oscillator tolerance for existing CAN protocol..................................................7-9
Oscillator tolerance for enhanced CAN protocol..............................................7-9
Resynchronization.................................................................................................7-10
Compatibility of existing and enhanced CAN protocols.........................................7-10
Assessment...........................................................................................................7-11
F
.
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com