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MC9S12HZ128VAL Datasheet, PDF (333/692 Pages) Freescale Semiconductor, Inc – MC9S12HZ256 Data Sheet, Rev. 2.05 | |||
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Chapter 12
Freescaleâs Scalable Controller Area Network (MSCANV2)
12.1 Introduction
Freescaleâs scalable controller area network (MSCAN) deï¬nition is based on the MSCAN12 deï¬nition,
which is the speciï¬c implementation of the MSCAN concept targeted for the M68HC12 microcontroller
family.
The module is a communication controller implementing the CAN 2.0A/B protocol as deï¬ned in the
Bosch speciï¬cation dated September 1991. For users to fully understand the MSCAN speciï¬cation, it is
recommended that the Bosch speciï¬cation be read ï¬rst to familiarize the reader with the terms and
concepts contained within this document.
Though not exclusively intended for automotive applications, CAN protocol is designed to meet the
speciï¬c requirements of a vehicle serial data bus: real-time processing, reliable operation in the EMI
environment of a vehicle, cost-effectiveness, and required bandwidth.
MSCAN uses an advanced buffer arrangement resulting in predictable real-time behavior and simpliï¬ed
application software.
12.1.1 Block Diagram
Oscillator Clock
Bus Clock
MSCAN
CANCLK
Tq Clk
MUX
Presc.
Receive/
Transmit
Engine
RXCAN
TXCAN
Transmit Interrupt Req.
Receive Interrupt Req.
Errors Interrupt Req.
Wake-Up Interrupt Req.
Control
and
Status
Message
Filtering
and
Buffering
Conï¬guration
Registers
Wake-Up
Low Pass Filter
Figure 12-1. MSCAN Block Diagram
MC9S12HZ256 Data Sheet, Rev. 2.05
Freescale Semiconductor
333
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