CAN Notes (5) protocol standard

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1. ISO standardized CAN protocol

After ISO standardized CAN protocol has two kinds of standard ISO11898 standards ISO11519-2 and
ISO11898 standards ISO11519-2 and defined the same for the data link layer, but different physical layers

• About ISO11898
  ISO11898 is the communication speed of 125kbps-1Mbps CAN-high-speed communication standard
  currently, after the addition of a new statute ISO11898, ISO11898-1 become the new standard
• About ISO11519
  ISO11519 communication speed is 125kbps less CAN speed communication standards
  ISO11519-2 ISO11519-1 is addition of a new version of the statute

CAN protocol and ISO11898 and ISO11519-2 standard range:

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2. ISO11898 and ISO11519-2 different points of

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2.1. Different physical layers

Physical layer of the CAN protocol as shown, defines three sub-layers

• PLS: Physical Signaling Sublayer (physical signal sublayer)
• PMA: Physical Medium Attachment (physical medium attachment)
• MDI: Medium Dependent Interface (Medium Dependent Interface)

ISO11898 and ISO11519-2 PMA layer and the physical layer MDI layers differ

The main difference in the physical layer (PMA layer, MDI layer), ISO11898 and ISO11519-2 of:

1. Communication speed
   transmission rate setting system according to
2. The length of the bus
   length of the bus system according to the set
   relationship communication speed and the maximum bus length is shown:
   
3. Bus Topology
   CAN bus transceiver according to two ( CAN_Highand CAN_Low) the potential difference determines the level of the bus
   level on the bus with a dominant level (Dominant level) and a recessive level (Recessive level) are two, the bus must be in two one species level power
   line on the logic "and" a dominant level logic value "0" ( "manifestation" easy to remember), the recessive level is "1" executed on the bus
   "dominant" having " priority "means that, as long as there is a dominant unit output level, is the dominant level on the bus
   " hidden "have" inclusive "means, only if all the units are output recessive level on the bus was implicit level of the
   dominant level greater than a recessive level
   in FIG characteristics of the physical layer:
   
   the ISO11898 to have a potential difference as to distinguish
   the beginning and ending ends of the CAN bus terminal has a 120Ω resistor, impedance matching done to reduce echo reflections
   ISO11519-2 a potential difference between the positive and negative value as a distinguishing

The main difference Table:

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2.2. Select the driver IC

ISO11898 standard ISO11519-2 and different physical layers, each size requires a dedicated driver IC corresponding thereto
corresponding to the primary driver IC Table:

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3. CAN standards and specifications

Not only is the ISO, SAE ¹ and other organizations, groups, companies also have standardized CAN protocol
based on CAN various standard Table:

Car-oriented communication protocol communication speed, whichever is classified:

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Reference:
"CAN Primer"

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Related Recommendation:
CAN Notes (4) the basic concepts of protocol
CAN Notes (3) the error state
CAN Notes (2) CAN features
CAN Notes (1) CAN Introduction

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Thank you!

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1. SAE: Society of Automotive Engineers (Society of Automotive Engineers) ↩︎