in on chip CAN protocols are available in some IC's.in that IC's CAN RX and CAN TX pins are available.but why we use the CAN transceiver IC for seperating the datas to CANH and CANL.pls answer detail about CAN communication.
The CAN Tx and Rx are single ended directional signals.
The transceiver IC simply translates these signals to/ from the actual medium (the wires) which require to be operated as bi-directional differential signals (CANH and CANL).
Note that Tx / Rx are NOT connected directly to CANH or CANL.
This is a physical layer issue.
The actual data transfer methods are what is implemented inside your CAN controllers (as defined by the CAN 'protocols'.)