Serial 10 CAN bus

Serial bus controller for CAN ina
Microcontroller

Serial CAN bus

CAN Device CAN Device CAN Device CAN Device

controller controller controller controller
Processor Processor Processor Processor of
of system 8 of system ^ of system D system E

Three standards:

1. 33 kbps CAN,

2. 110 kbps Fault Tolerant CAN,
3. 1 Mbps High Speed CAN

CAN protocol
There is a CAN controller between the CAN line and the host node.

_ CAN controller -BIU (Bus Interface Unit) consisting of a buffer and driver
_ Method for arbitration- CSMA/AMP(Carrier Sense Multiple Access with Arbitration on
Message Priority basis)

Each Distributed Node Uses:

* Twisted Pair Connection up to 40 m —-for bi-directional data
* Line, which pulls to Logic 1 through a resistor between the line and + 4.5V to +12V.
* Line Idle state Logic 1 (Recessive state)

* Uses a buffer gate between an input pin and the CAN line

* Detects Input Presence at the CAN line pulled down to dominant (active) state logic 0
(ground ~OV) by a sender to the CAN line
* Uses a current driver between the output pin and CAN line and pulls line down to

dominant (active) state logic O(ground ~ 0५9) when sending to the CAN line Protocol