MC68HC55SLASHD datasheet(2/40 Pages) FREESCALE

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MC68HC55 Technical Data

Technical Data

MC68HC55

DSI/D (Distributed System Interface – Digital)

Section 1. DSI/D (Distributed System Interface – Digital)

The distributed system interface uses a 2-wire bus to interconnect a

master controller with sensors and firing units in an airbag system or

other automotive body control applications. Remote units are a key

feature of this system because they do not require a crystal or other

critical timing reference components which might be damaged in a

crash.

This document describes a 2-channel CMOS (complmenetary

metal-oxide semiconductor) ASIC (application-specific integrated

circuit) device, the MC68HC55. It communicates with the (master) serial

peripheral interface (SPI) from an MCU and generates interface signals

to/from an analog SmartMOS™ device called the DSI/P (where P

indicates the physical layer of the DSI system). 1.2 General Description

of the DSI System

gives a general overview of the distributed system

interface (DSI), providing a context for understanding the details of this

specification.

1.1 Features

Features of the MC68HC55 include:

• Compact 16-pin narrow body SOIC (small outline integrated

circuit) package

• Compatible with Freescale SPI (serial peripheral interface)

communication interface

• Compatible with DSI/P analog ASIC

• Two independent DSI channels

• Pin assignments match DSI/P for easy connection

• Automatic CRC (cyclical redundancy check) generation and

checking for robust message verification

• 4-stage transmit and receive FIFOs (first in, first out)

• 8-bit or 16-bit messages, plus 4-bit CRC

SmartMOS is a trademark of Freescale Semiconductor, Inc.

MC68HC55/D Datasheet(PDF) 2 Page - Freescale Semiconductor, Inc