`
`HUTflMflTIVE
`
`
`
`Liberty
`Mutual
`
`Exhibit 1018
`
`
`* Pe cmooo
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`Page 000001
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`
`
`
`
`AUTOMOTIVE
`
`ELECTRONICS
`
`
`
`HANDBOOK
`
`Ronald K. Jurgen Editorin Chief
`
`McGraw-Hill, Inc.
`NewYork SanFrancisco WashingtonD‘C, Auckland Bogota
`Caracas Lisbon London Madrid MexicoCity Milan
`Montreal NewDelhi SanJuan Singapore
`Sydney Tokyo Toronto
`
`Page 000002
`
`Page 000002
`
`
`
`Library of Congress Cataloging-in~Publication Data
`
`Automotive electronics handbook / Ronald Jurgen, editor in chief.
`p.
`cm.
`Includes index.
`ISBN 0-07-033189-8
`1. AutomobilesiElectronic equipment.
`TL272.5.A982
`1994
`629.25‘49—dc
`
`I. Jurgen, Ronald K.
`
`94739724
`CIP
`
`Copyright © 1995 by McGraW-Hill, Inc. All rights reserved. Printed in the
`United States of America. Except as permitted under the United States
`Copyright Act of 1976, no part of this publication may be reproduced or dis-
`tributed in any form or by any means, or stored in a data base or retrieval
`system, without the prior written permission of the publisher.
`
`1234567890 AGM/AGM 90987654
`
`ISBN 0-07033189—8
`
`The sponsoring editor for this book was Stephen S. Chapman, the editing
`supervisor was Virginia Carroll, and the production supervisor was
`Suzanne W. B. Rapcavage. It was set in Times Roman by North Market
`Street Graphics.
`
`Printed and bound by Areata Graphics/Martinsburg.
`
`McGraw-Hill books are available at special quantity discounts to use as pre»
`miums and sales promotions, or for use in corporate training programs. For
`more information, please write to the Director of Special Sales. McGraw-
`Hill, Inc, 11 West 19th Street, New York, NY 1001 1. Or contact your local
`bookstore.
`
`Information contained in this work has been obtained by McGraw-
`Hill, Inc. from sources believed to be reliable. However, neither
`McGraw-Hill nor its authors guarantee the accuracy or complete-
`ness of any information published herein, and neither McGraw
`Hill nor its authors shall be responsible for any errors, omissions,
`or damages arising out of use of this information. This work is
`published with the understanding that McGraw-Hill and its authors
`are supplying information, but are not attempting to render engi-
`neering or other professional services.
`If such services are
`required, the assistance of an appropriate professional should be
`
`sought,
`
`This book is printed on acid-free paper.
`
`Page 000003
`
`Page 000003
`
`
`
`11.24
`
`CONTROL SYSTEMS
`
`Ambient temperature under bias (TA) refers to the temperature range that the microcon—
`troller is guaranteed to operate at within a given application. While powered—up or operating,
`a microcontroller must not be subjected to temperatures that exceed its specified ambient
`temperature rangeThe most common ambient temperature ranges in industry are:
`Commercial
`0 to +70 °C
`Extended
`40 to +85 °C
`Automotive
`+40 to +125 °C
`
`175 MEMBRV
`
`Microcontrollers execute customized programs that are written by the user. These programs
`are stored in either on-chip or off-chip memory and are often referred to as the user‘s code. On-
`chip memory is actually integrated onto the same piece of silicon as the microcontroller and is
`accessed over the internal data bus. Off-chip memory exists on a separately packaged piece of
`silicon and is typically accessed by the microcontroller over an external address/data bus
`A memory map shows how memory addresses are arranged in a particular microcon-
`troller. Figure 11.19 shows a typical microcontroller memory map.
`
`
`
`
`1 Memory FunctionAddress ;
`
`
`
`
`
`
`
`_
`
`.
`
`_
`
`_
`
`2000h
`1FFFh
`
`_
`
`_
`
`.1 F99".
`iEFFh
`
`0400i:
`03FFh
`
`_
`
`_
`
`
`
`l ___________ W9”? Pitt???” WWW”).
`.9199".
`Register RAM
`megseaifie‘rflii;
`OOFFh
`_
`_
`. .999". _____________ Indirect or indexed
`
`
`32:): Md”) CPU SFFis
`FIGURE 11.19 Microcontroller memory map.
`
`Extemel Memory
`
`Internal ROM/EPROM or External Memory
`(Interrupt vectors. 008's. Sewmy Key. Reeerved buttons, etc.)
`
`internal Special Function Registers (SFR's)
`l
`.1 ,,,,,,,,,,,,,,,,,,,,,,,,,,,
`l
`
`External Memory
`
`0600b 7
`O5FFh """""""""""""""
`IN1ERNAL RAM (Address with Indirect or Indexed modes.)
`(Aloe imow .- Code RAM)
`
`imam Rattlesnllzam
`
`Reglstor
`File
`
`Page 000004
`
`
`
`r
`
`Page 000004
`
`
`
`AUTOMOTIVE MICROCONTROILERS
`
`11.25
`
`Memory is commonly referred to in terms of Kbytes of memory. One Kbyte is defined as
`1024 bytes of data. Memory is most commonly arranged in bytes which consist of 8 bits of
`data. For instance, a common automotive EPROM is referred to as a “256k x 8 EPROM”.This
`EPROM contains 256—Kbytes 8-bit memory locations or 2.097.152 bits of information.
`
`11.2.1 On-Chip Memory
`
`On—chip microcontroller memory consists of some mix of five basic types: random access mem-
`ory (RAM), read—only memory (ROM), erasable ROM (EPROM), electrically erasable ROM
`(EPROM), and flash memory. RAM is typically utilized for run—time variable storage and
`SFRs.1he various types of ROM are generally used for code storage and fixed data tables.
`The advantages of on-chip memory are numerous. especially for automotive applications.
`which are very size and cost conscious. Utilizing on-chip memory eliminates the need for
`external memory and the “glue” logic necessary to implement an address/data bus system.
`External memory systems are also notorious generators of switching noise and RFI due to
`their high clock rates and fast switching times. Providing sufficient on—chip memory helps to
`greatly reduce these concerns.
`
`RAM. RAM may be defined as memory that has both read and write capabilities so that the
`stored information can be retrieved (read) and changed by applying new information to the
`cell (write). RAM found on microcontrollers is that of the static type that uses transistor cells
`connected as flip-flops. A typical six—transistor CMOS RAM cell is shown in Fig. 1 1.20. It con—
`sists of two cross—coupled CMOS inverters to store the data and two transmission gates, which
`provide the data path into or out of the cell. The most significant characteristic of static mem-
`ory is that it loses its memory contents once power is removed. After power is removed, and
`once it is reapplied, static microcontroller RAM locations will revert to their default state of
`a logic “0”. Because of the number of transistors used to construct a single cell. RAM mem—
`ory is typically larger per bit than EPROM or ROM memory.
`Although code typically cannot be executed from register RAM. a special type of RAM
`often referred to as code RAM is useful for downloading small segments of executable code.
`The difference between code and register RAM is that code RAM can be accessed via the
`
`Vec
`
`Vec
`
`
`to nl cells
`'3 ll 09“.
`In 00‘1“" <
`.
`'
`) In column
`
`
`
`
`Tmnsmbsbn Gate
`E TransmissbnGate
`
`—c
`
`mi 9
`
`
`
`
`tnRMl='0'.
`
`3. 1..
`
`
`
`%
`
`NVW='°'-
`
`FIGURE 11.20 CMOS RAM memory cell.
`
`Va
`
`Vs:
`
`Page 000005
`
`Page 000005
`
`
`
`11.26
`
`CONTROL SYSTEMS
`
`memory controller, thus allowing code to be executed from it. Code RAM is especially useful
`for end-of—line testing during ECU manufacturing by allowing test code to be downloaded via
`the serial port peripheral.
`
`ROM. Read»only memory (ROM), as the name implies. is memory that can be read but not
`written to. ROM is used for storage of user code or data that does not change since it is a non-
`volatile memory that retains its contents after power is removed. Code or data is either
`entered during the manufacturing process (masked ROM, or MROM) or by later program
`ming (programmable ROM. or PROM): either way, once entered it is unalterable.
`A ROM cell by itself (Fig. 11 .21) is nothing more than a transistorl ROM cells must be used
`in a matrix of word and bit lines (as shown in Fig. 11.22) in order to store information The
`word lines are connected to the address decoder and the bit lines are connected to output
`buffersThe user‘s code is permanently stored by including or omitting individual cells at word
`and bit line junctions within the ROM array. For MROMs. this is done during wafer fabrica-
`tion. For PROMs, this is done by blowing a fuse in the source/drain connection of each cell.T0
`read an address within the array, the address decoder applies the address to the memory
`matrix. For any given intersection of a word and bit line, the absence of a cell transistor allows
`no current to flow and causes the transistor to be offThis indicates an unprogrammed ROM
`cell. The presence of a complete cell conducts and is sensed as a logical ““,0 indicating a pro-
`grammed cell. The stored data on the bit lines is then driven to the output buffers.
`MROMs are typically used for applications whose code is stable and in volume produc-
`tion. After the development process is complete and the user’s program has been verified, the
`user submits the ROM code to the microcontroller manufacturer.The microcontroller manu—
`facturer then produces a mask that is used during manufacturing to permanently embed the
`program within the microcontroller. This mask layer either enables or disables individual
`ROM cells at the junctions of the word and bit lines. An advantage of MROM microcon-
`trollers is that they come with riser code embedded, which saves time and money since post—
`production programming is not necessary. A disadvantage of MROM devices is that. since the
`mask with the user code has to be supplied early in the manufacturing process. throughput
`time (TPT) is longer.
`Some versions of ROM (such as Intel‘s Quick-ROM) are actually not ROMS, but rather
`EPROMs, which are programmed at the factory. These devices are packaged in plastic
`devices. which prevents them from being erased since ultraviolet light cannot be applied to
`the actual EPROM array. Throughput time for OROMs is faster since the user code isn’t
`required until after the actual manufacturing of the microcontroller is complete. As with
`
`W D
`
`RAIN
`
`W
`
`(GATE)
`
`
`GATE OX]DE
`
`
`
`PWTE
`
`m
`
`m ME
`
`FIGURE 11.21 ROM memory cell.
`
`Page 000006
`
`Page 000006
`
`
`
`AUTOMOTIVE MlCROCONTROLLERS
`
`11.27
`
`WORD lines from address decoder
`
`0
`
`1
`
`2
`
`3
`
`
`
`
`
`
`
`
`BITlinestooutputbuffers
`
`FIGURE 11.22 Simplified ROM memory matrix‘
`
`MROMs, the user supplies the ROM code to the microcontrollcr manufacturer. Instead of
`creating a mask with the ROM code, the manufacturer programs it into the device just prior
`to final test.
`
`EPROM. EPROM devices are typically used during application development since this is
`when user code is changed often. EPROMs are delivered to the user unprogrammed. This
`allows the user to program the code into memory just prior to installation into an ECU mod-
`ule. Many EPROM microcontrollers actually provide a mechanism for in-module program-
`ming. This feature allows the user to program the device via the serial port while it is installed
`in the module. EPROM devices come assembled in packages either with or without a trans
`parent window. Windowed devices are true EPROM devices that allow the user to erase the
`memory contents by exposing the EPROM array to ultraviolet light. These devices may be
`reprogrammed over and over again and thus are ideally suited for system development and
`debug during which code is changed often. EPROM devices assembled in a package without a
`window are commonly referred to as one-time programmable devices or OTPs. OTPs may only
`be programmed once, since the absence of a transparent window prevents UV erasure. OTPs
`are suited for limited production validation (PV) builds in which the code will not be erased.
`A typical EPROM cell is shown in Fig. 11.23. It is basically an N-channel transistor that has
`an added polyl floating gate to store charge. This floating gate is not connected and is sur—
`rounded by insulating oxide that prevents electron flow. The mechanism used to program an
`EPROM cell is known as hot electron injection. Hot electron injection occurs when very high
`drain (9—V) and select gate (12-V) voltages are appliedThis gives the negatively charged elec-
`trons enough energy to surmount the oxide barrier and allows them to be stored on the gate.
`
`Page 000007
`
`Page 000007
`
`
`
`11.23
`
`CONTROL SYSTEMS
`
`This has the same effect as a negative applied gate voltage and turns the transistor off. When
`the cell is unprogrammed, it can be turned on like a normal transistor by applying 5 V to the
`poly2 select gate. When it is programmed. the 5 V will not turn on the eell.’l‘he state of the cell
`is determined by attempting to turn on the cell and detecting if it turns on. Erasure is per-
`formed through the application of ultraviolet (UV) light. which gives just the right amount of
`energy necessary for negatively charged electrons to surmount the oxide barrier and leave the
`floating gate.
`
`Dhamn
`
`(GATE
`
`WW
`
`GATE ONDE
`
`
`
`was,
`
`mm
`
`l
`M % H E
`
`PSUBS’TRATE
`
`FIGURE 11.23 EPROM memory cell.
`
`Flash memory is the newest nonvolatile memory technology and is very similar to
`Flash.
`EPROM.The key difference is that flash memory can be electrically erased. Once programmed,
`flash memory contents remain intact until an erase cycle is initiated via software. Like EEPROM,
`flash memory requires a programming and erase voltage of approximately 12.0V. Since a clean,
`regulated 12—V reference is not readily available in automotive environments this need is often
`provided for through the incorporation of an on-chip charge pump. The charge pump produces
`the voltage and current necessary for programming and erasure from the standard 57V supply
`voltage. The advantage of flash is in its capability to be programmed and erased in—module with-
`out having to be removed. Inrmodule reprogrammability is desirable since in—vehicle validation
`testing doesn’t always allow for easy access to the microcontroller. Flash also allows for last-
`minute code changes. data table upgrades. and general code customization during ECU assem-
`bly. Since a flash cell is nearly identical in size to that of an EPROM cell, the high reliability and
`high device density capable with EPROM is retained.The main disadvantage of flash is the need
`for an on-chip charge pump and special program and erase circuitry. which adds cost.
`A flash memory cell is essentially the same as an EPROM cell, with the exception of the
`floating gate. The difference is a thin oxide layer which allows the cell to be electrically erased.
`The mechanism used to erase data is known as [-‘owler-Nordheim tunneling, which allows the
`charge to be transferred from the floating gate when a large enough field is created. Hot elec-
`tron injection is the mechanism used to program a cell, exactly as is done with EPROM cells.
`When the floating gate is positively charged, the cell will read a “1”. when negatively charged,
`the cell will read a “’10
`
`charge pump as is done for flash memory arrays. Like flash, the advantage of EEPROM is its
`
`EEPROM. EEPROM (electrically erasable and programmable ROM. commonly referred to
`as EZROM) is a ROM that can be electrically erased and programmed. Once programmed,EEP—
`ROM contents remain intact until an erase cycle is initiated via software. Like flash, programming
`and erase voltages of approximately 12 V are required. Since a clean, regulated 12-V reference is
`not readily available in automotive environments, this requirement is satisfied using an on-chip
`
`Page 000008
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`Page 000008
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`
`
`AUTOMOTIVE MICROCONTROLLERS
`
`11.29
`
`capability to be programmed and erased in—module.This allows the user to erase and program the
`device in the module without having to remove it. EEPROM‘s most significant disadvantage is
`the need for an on-chip charge pump. Special program and erase circuitry also adds cost.
`An EEPROM cell is essentially the same as an EPROM cell with the exception of the
`floating gate being isolated by a thin oxide layer. The main difference from flash is that
`Fowler-Nordheim electron tunneling is used for both programming and erasure. This mecha«
`nism allows charge to be transferred to or from the floating gate (depending upon the polar—
`ity of the field) when a large enough field is created. When the floating gate is positively
`charged, the cell will read a “1”; when negatively charged, the cell will read a "0”,
`
`11.2.2 Off-Chip Memory
`
`Off—chip memory offers the most flexibility to the system designer. but at a price: it takes up
`additional PCB real estate as well as additional I/O pins. ln cost« and size-conscience applica-
`tions. such as automotive ABS, system designers almost exclusively use on-chip memory.
`However, when memory requirements grow to sizes in excess of what is offered on-chip (such
`as is common in electronic engine control), the system designer must implement an off—chip
`memory system. Off-chip memory is flexible because the user can implement various memory
`devices in the configuration of his choice Most microcontrollers on the market today offer a
`wide variety of control pins and timing modes to allow the system designer flexibility when
`interfacing to a wide range of external memory systems.
`
`1f circuit designers must use external memory in their appli-
`Accessing External Memory.
`cations, the type of external address/data bus incorporated onto the microcontroller should be
`considered. If external memory is not used, this will have. if any, impact upon the application.
`There are two basic types of interfaces used in external memory systems. Both of these are
`parallel interfaces in which bits of data are moved in a parallel fashion and are referred to as
`multiplexed and demulriplexed address/data buses.
`
`Multiplexed Address/Data Buses. As the name implies, multiplexed address/data buses
`allow the address as well as the data to be passed over the same microeontroller pins by mul-
`tiplexing the two in time. Figure 11.24 illustrates a typical multiplexed 16-bit address/data bus
`system as is implemented with Intel‘s 8XCl9on family of microcontrollers.
`
`
`
`
`
`E:—s
`
`
`
`EPROM
`
`DATA
`(Low)
`
`
`DATA
`=I
`
`EPROM
`
`
`(High)
`
`LOW ADDRESS
`LOW ADDRESS
`
`
`
`II7;:II HIGHADDRESS I HIGHADDRESS
`lllliiiiEi1||||l
`
`
`ALE I ADV
`
`373
`
`
`
`FIGURE 11.24 Multiplexed address/data bus system.
`
`Page 000009
`
`Page 000009
`
`