MC9S12KG128 Datasheet, PDF (271/600 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 9
Freescale’s Scalable Controller Area Network (MSCANV2)
9.1 Introduction
Freescale’s scalable controller area network (MSCAN) definition is based on the MSCAN12 definition,
which is the specific 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 defined in the
Bosch specification dated September 1991. For users to fully understand the MSCAN specification, it is
recommended that the Bosch specification be read first 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
specific 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 simplified
application software.
9.1.1 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
Configuration
Registers
Wake-Up
Low Pass Filter
Figure 9-1. MSCAN Block Diagram
MC9S12KG128 Data Sheet, Rev. 1.15
Freescale Semiconductor
271