MC9S12HY64 Datasheet, PDF (310/792 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

Freescale’s Scalable Controller Area Network (S12MSCANV3)
9.2 External Signal Description
The MSCAN uses two external pins.
NOTE
On MCUs with an integrated CAN physical interface (transceiver) the
MSCAN interface is connected internally to the transceiver interface. In
these cases the external availability of signals TXCAN and RXCAN is
optional.
9.2.1 RXCAN — CAN Receiver Input Pin
RXCAN is the MSCAN receiver input pin.
9.2.2 TXCAN — CAN Transmitter Output Pin
TXCAN is the MSCAN transmitter output pin. The TXCAN output pin represents the logic level on the
CAN bus:
0 = Dominant state
1 = Recessive state
9.2.3 CAN System
A typical CAN system with MSCAN is shown in Figure 9-2. Each CAN station is connected physically
to the CAN bus lines through a transceiver device. The transceiver is capable of driving the large current
needed for the CAN bus and has current protection against defective CAN or defective stations.
CAN node 1
MCU
CAN Controller
(MSCAN)
CAN node 2
TXCAN
RXCAN
Transceiver
CANH
CANL
CAN Bus
CAN node n
Figure 9-2. CAN System
MC9S12HY/HA-Family Reference Manual, Rev. 1.04
310
Freescale Semiconductor