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FlexRay - Difference with CAN | Cypress Semiconductor

FlexRay - Difference with CAN

 Background |  Overview |  Features |  In-car Communication Protocol |  Target applications |  Data transfer method |  Difference with CAN |  Internal configuration of a node |  Electronic signals |  Bus Guardian |  Topology |  Segment configuration |  Protocol |  Status transition |  Error control |

FlexRay ASSP

The following table shows the comparison of major specifications of FlexRay and CAN.

Comparison between FlexRay and CAN

No. Compared item CAN FlexRay
1 Baud rate 1Mbps 10Mbps
2 Number of channels per a node 1ch 2ch/1ch (option(1))
3 Network topology Bus-type Bus-type, Star-type, or Coexisting
4 Connected nodes (max) Depending on the delay time of the bus Bus-type: 22 nodes Star-type: 22 nodes or 64 nodes during active Coexisting: 64 nodes
5 Physical layer Metal Metal/PoF
6 Communication Event trigger Time trigger + event trigger
7 ID 11bits/29bits 11bits
8 DLC 8bytes 254bytes
9 Frame Data Frame,

Remote Frame,

Error Frame,

Over Rode Frame
Data Frame
10 Bus line lock Possibly bedominant lock(2) Babbling Idiot(3) (supported by BG(4))
11 Error status transition Error Active,

Error Passive,

Bus off (recoverable by software)
Normal Active,

Normal Passive,

Halt (recoverable by a reset or software command)
12 Error counter Fixed status transition counter value Arbitrary status transition counter value
13 Type of errors Bit Error,

Staffing Error,

CRC Error,

Framing Error,

ACK Error
All errors except a clock synchronization
14 Oscillator Ceramic oscillator or crystal oscillator Crystal oscillator

(BG(4) is separated from the CC(5) clock)
15 NW management By software By hardware (by BD(6) or BG)
16 Network synchronization Synchronized only by sync_seg Rate correction and offset correction are available.
17 Bus length 40m at 1Mbps 22m

(between nodes, between Active-Star and node, and between Active-Star and Active-Star.)


The option means it can be switched by the setting value.
dominant lock:
Dominant lock means that Bus is stuck to "0".
Babbling Idiot:
Babbling Idiot means that incorrect transfer causing damage occurs.
BG stands for bus guardian.
CC stands for communication controller.
BD stands for bus driver.

- Note -

Some parts of this site show only the outlines of the actual FlexRay standards to make them easily understood.