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Chapter 16 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XE-Family Reference Manual Rev. 1.07
Freescale Semiconductor
623
Flexible maskable identifier filter supports two full-size (32-bit) extended identifier filters, or four
16-bit filters, or eight 8-bit filters
Programmable wakeup functionality with integrated low-pass filter
Programmable loopback mode supports self-test operation
Programmable listen-only mode for monitoring of CAN bus
Programmable bus-off recovery functionality
Separate signalling and interrupt capabilities for all CAN receiver and transmitter error states
(warning, error passive, bus-off)
Programmable MSCAN clock source either bus clock or oscillator clock
Internal timer for time-stamping of received and transmitted messages
Three low-power modes: sleep, power down, and MSCAN enable
Global initialization of configuration registers
16.1.4
Modes of Operation
ThefollowingmodesofoperationarespecifictotheMSCAN.See
Section 16.4,“FunctionalDescription
,”
for details.
Listen-Only Mode
MSCAN Sleep Mode
MSCAN Initialization Mode
MSCAN Power Down Mode
16.2
External Signal Description
The MSCAN uses two external pins:
16.2.1
RXCAN — CAN Receiver Input Pin
RXCAN is the MSCAN receiver input pin.
16.2.2
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
16.2.3
CAN System
A typical CAN system with MSCAN is shown in
Figure 16-2
. 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.