Hitachi Review 1

“SH-Mobile” LSIs for Cell Phones

OVERVIEW: With the increasing number of functions performed by cellphones, processors are faced with demand for advanced multimediaprocessing capabilities. Coping with services that are offered by third-generation cell phones, such as videophone and video distribution, is difficultfor the CPUs of the base band LSI chips of conventional cell phones. Thatpoints to the need for an application processor to strengthen multimediaprocessing. Furthermore, the increased software development work neededto cope with this multifunctionality is also becoming a problem for systemdevelopment. Hitachi has developed the SH-Mobile Series RISCmicroprocessors to strengthen multimedia processing performance and thepower conservation function for cell phones with advanced functions. TheSH-Mobile Series answers the needs for advanced system functionality andshorter development time by providing basic cell-phone middleware and anapplication development platform together with the LSI. Furthermore, weare expanding the product line-up to cope with diversification ofspecifications.

Toshinobu Kanai

Hiroshi Yagi

Junichi Nishimoto

Ikuya Kawasaki

INTRODUCTIONTHERE has been steady progress in diversification ofcell phone services over time, beginning with the first-generation analog systems, passing through thesecond-generation digital systems, and on to theinception of true third-generation services in 2001,with international roaming and high-speed data

communication. The first and second generation cellphones mainly featured voice services, e-mail and webbrowsing services and incoming call melodies. At thestage of transition to the third generation, however,functions for color liquid crystal display (LCD)screens, reception of still and moving pictures, audioplayback, and application programs written in Java or

Fig. 1—Applications Required forCell Phones.This shows the change inapplications by cell phonegeneration. Beginning withgeneration 2.5 cell phones, anapplication processor that hasadvanced functions is required formultimedia processing, such asaudio, still images and video.

Large

Small

Operationload

Second generation Generation 2.5 Third-generation

Videophone (MPEG-4 CODEC)

*1: Java and all Java related trademarks and logos are registered trademarks of Sun Microsystems, Inc. in the United States and other countries.

*2: Bluetooth is a trademark of Bluetooth SIG, Inc. of the United States. Hitachi, Ltd. uses this under a license contract.

Video mail (MPEG-4 encoding)Video download

(MPEG-4 decoding)

Incoming call melody (32 chords)

Incoming call melody(16 chords) Music distribution

(MP3/AAC)

Incoming call melody (8 chords)

Data communication (384 kbit/s)

Data communication (144 kbit/s)

Data communication (64 kbit/s)

Wireless (Bluetooth*2)

High-speed Internetgraphics

Location information

JPEGJava*1

Web browser

Character conversion

MPEG-4: Moving Pictures Experts Group-4JPEG: Joint Photographic Experts GroupMP3: MPEG-1 audio layer 3AAC: adaptive audio codingCODEC: coder-decoder

“SH-Mobile” LSIs for Cell Phones 2

other such languages are being added as what couldbe called generation 2.5. For the third-generation,video distribution by means of MPEG-4 (MovingPictures Experts Group-4), high performance Java,videophone, and other such new services that makeuse of the high-speed data communication feature arebeing introduced (see Fig. 1).

These new applications require the processingperformance of advanced processors, so it is difficultto perform all of the processing with the CPUs (centralprocessing unit) that conventional base bandprocessors have. That has prompted a conspicuousmovement to reconsider the configuration of the cellphone system and supplement the base band processorwith a new CPU for performing application processing.In response to that call, Hitachi is bringing to fruition

the SH-Mobile Series of LSI chips, which are designedas application processors for cell phones.

Here, we describe the performance, features andfuture development of the SH-Mobile Series.

SH-MOBILE SERIES APPLICATIONPROCESSORS FOR CELL PHONES

An example of the system configuration of cellphone systems up to the second generation is presentedin Fig. 2 (a); an example of later system configurationsis shown in (b) of the same figure. In systems up tothe second generation, all of the processing for audio,LCD control, key control, RF (radio frequency) controland other such functions is done by the base band LSI.Although the application processing is beginning tobe dealt with by increasing the speed and expandingthe functionality of the base band LSI, the difficultyof improving the performance of the base band LSI ina single step and the increase in application softwaredevelopment work that will come with future advancesin system functionality have been pointed out asproblems.

On the other hand, the second generation andsubsequent cell phone systems of Fig. 2 (b) comprisetwo CPUs, a base band LSI and an applicationprocessor (AP). The base band LSI handles thetelephone functions and the AP handles otherapplications, including e-mail, Java, MPEG-4, musicplayback, key control and LCD control. With thatconfiguration, the application processing that wouldbe a large burden on the base band LSI is assigned tothe AP. Furthermore, by introducing a configurationin which power to the AP can be cut off when anapplication is not being used, it is possible to avertboth the increase in load on the base band LSI requiredfor normal operation and the increase in overall systempower consumption.

The system configuration for the SH-Mobile1SH7290, a representative product of the SH-MobileSeries that was developed to serve as applicationprocessors for cell phones, is shown in Fig. 3. TheSH-Mobile1 is an LSI chip that integrates, on a singlechip, an SH3-DSP CPU core that has a maximumoperating frequency of 133 MHz, a 16-kbyte X/Ymemory (XY-RAM) for the DSP (digital signalprocessor), a 32-kbyte cache memory, a 128-kbyte usermemory (URAM) and the various peripheral functionsrequired by a cell phone system. The performance ofthis processor is equivalent to the processors that arealready in use in hand-held computers and other suchdevices, and can fully cope with the ever increasing

Fig. 2—Examples of Cell Phone System Configuration.The configuration for up to the second generation, shown in (a),assigns all of the processing for the various applications as wellas the telephone functions to the base band LSI. The systemconfiguration shown in (b) adds a second processor, anapplication processor, which makes various kinds of processingpossible.

(a) An example of cell phone system configuration for up to the second generation

(b) An example of cell phone system configuration for second and subsequent generations

Microphone

Microphone

Speaker

Speaker

Key

Key

Tone generator IC

Tone generator IC

Power supply control IC

Power supply control IC

Base band

Base band

Application processor

RF

RF

ROM

ROM

ROM

SRAM

SRAM

SRAM

Flash memory

Flash memory

Flash memory

LCD

LCD

BluetoothMemory card

RF: radio frequencyROM: read-only memory

SRAM: static random access memoryLCD: liquid crystal display

Hitachi Review 3

types of multimedia processing. Furthermore, theburden of software development is reduced byproviding abundant middleware and a developmentenvironment all together. The special features of theSH-Mobile Series are described in the followingsection.

BASIC SUPPORT TECHNOLOGY FOR THESH-MOBILE SERIESMethod of Connection with the Base Band LSI

Existing cell phones use a wide variety of base bandLSIs; the choice depends on the terminal manufacturerand the communication system. The SH-Mobile Seriesintroduces a multi-function interface (MFI) functionthat ensures connectivity to various base band LSIs.The MFI has a parallel interface that can be switchedbetween 8- and 16-bit widths and between 68 seriesand 80 series formats, making it possible to connectdirectly to the SRAM ports of nearly all base bandLSIs (Fig. 3). SH-Mobile contains a dual-port (two-port) RAM that is called a “communication RAM”and is connected to the MFI and BSC (bus statecontroller). With the communication RAM asintermediary, data can be exchanged with both the baseband LSI and SH-Mobile by the same procedure as isused when accessing ordinary SRAM. Also, the SH-Mobile, which is an AP, can operate in completesubordination to the base band LSI. That allows use

to be made of the software assets that were developedfor systems in which the conventional base band LSIis the master processor, with the aim of introducingan AP.

Power Conservation and the LCD Through PathIn the system shown in Fig. 3, the color LCD, which

requires the transfer of large quantities of data, isconnected to the system bus of the SH-Mobile, whichhas superior data transfer capability. That allows thedisplay of video and other high-speed images. On theother hand, for the reduction in power consumption,the SH-Mobile Series introduces a power conservationmode called the “U-standby mode.” In that mode, mostof the power to the LSI is cut off at times when APoperation is not required, such as when the phone is instandby mode. However, it was anticipated that displayto the LCD would not be possible during U-standbywhen the LCD was connected to the system bus. Tosolve that problem, an LCD through path that allowsdirect connection of the MFI and the system bus duringU-standby was incorporated. The LCD can becontrolled directly from the base band LSI during U-standby by using the LCD through path. Duringstandby, only the base band LSI operates, just as in aconventional system, thus making it possible to realizea system in which the AP is invoked to do applicationprocessing only when it is necessary.

Fig. 3—SH-Mobile1 SH7290Configuration and SystemConstruction Example.This shows the function blocks of theSH-Mobile1 SH7290 and anexample of the construction of a cellphone system. The CPU and internalmemory, as well as variousperipheral functions are integratedon one chip.

Flash memory SRAM

BB: basebandMFI: multi-function interfaceI/F: interfaceXY-RAM: X/Y random access memoryURAM: user RAMBSC: bus state controllerI2C bus: inter IC busUART: universal asynchronous receiver-transmitter

SIOF: serial input and output with first in, first outDMAC: direct memory access controllerUSB: universal serial busADC: analog-to-digital converterWDT: watchdog timerUBC: user break controllerPNG: portable network graphicsPCM: programmable control module

RFBBLSI

SH3-DSP133 MHz

8/16-bit MFI (68/80 I/F)

32-kbyte cache

16-kbyte XY-RAM

128-kbyte URAM

SH7290

Camera module

Communication RAM LCD through path

BSCSRAMExternal flash memory

8 bits Visual engine

UART/SIOFDMACUSB/ADC/WDTPeripheral functions such as UBC, and key I/F

Java engine for middleware, MPEG-4, JPEG/PNG, MP3/AAC, etc.

Command

Key scan

I2C busMemory card I/F

Audio

Flash memory

SRAM

For 260,000 colors LCD

PCM CODECAudio CODECFM IC

Dec. 24 Mon 00:00

“SH-Mobile” LSIs for Cell Phones 4

*: µITRON is the abbreviation for “Micro Industrial TRON.” TRON isthe abbreviation for “The Real-time Operating system Nucleus,” real-time operating system specifications proposed by Professor KenSakamura of the University of Tokyo.

Visual EngineOne new service for cell phones that is gradually

increasing is the terminal that is equipped with acamera. The SH-Mobile Series introduced a “visualengine,” which connects directly to a camera modulethat combines a camera DSP with a sensing device,such as a CMOS (complementary metal-oxidesemiconductor) sensor. The visual engine provideshardware processing for reading the captured imagedata and for format conversion. It has an I2C businterface for accessing an 8-bit data bus and theregisters in the camera module. The SH-Mobile1 iscapable of still and motion image processing up toCIF (common intermediate format) size. The imagesize for which processing is possible will probablyincrease with the development of new products for theline-up (see Fig. 4).

APPLICATION DEVELOPMENT ENVIRONMENTAND SOFTWARE SOLUTIONSSolution Engine

For the SH-Mobile Series, a software platform thathas the kind of configuration shown in Fig. 5 isprovided. The core is the “solution engine,” adevelopment board for concentrating all of the SH-Mobile chip and peripheral devices that are requiredfor a cell phones system, such as the LCD panel,CMOS camera module, key switch and various typesof memory (see Fig. 6).

Middleware SupportThe SH-Mobile development environment

provides, in addition to the hardware drivers, an

operating system (OS) such as “µITRON*,” imageprocessing such as for MPEG-4 and JPEG images,audio processing such as for MP3 and AAC formats,

Fig. 4—SH-Mobile Series ProductRoad Map.

The product line-up is beingsupplemented to strengthen

multimedia processing performance.

Fig. 5—Example of SH-Mobile Series Software PlatformConfiguration.Hitachi and partner manufacturers provide customers withhardware (the Solution Engine), drivers, OS (µITRON), andvarious types of middleware in a single package, thus allowingthe customer to concentrate on application development.

AMR: audio/modem riserµITRON: Micro Industrial The Real-time Operating system NucleusGPIO: general-purpose input-output portSIO: serial input and outputVIO: video input and outputSIM: smart card interface module

Customer application software

Music playback, incoming call melody, video (MPEG) playback, phone directory, games, encryption, etc.

API

Java 3-D engine

Customer original middleware

AACMP3AMR

MPEG-4JPEGPNG

µITRON

SH-Mobile hardware driversBas

e ba

nd L

SI I

/F s

oftw

are

SH-MobileSolution engine (development board)

MFI UART ADC GPIO SIO SIOF LCD USB SIMVIOcamera

Timer

Current productPerformance

0.18-µm core

0.18-µm coreFor VGA camera

0.15-µm coreFor MPEG-4 accelerator, videophoneJava accelerator3-D graphics

0.15-µm coreUpward compatible with SH-Mobile V

0.13-µm coreNew mobile corewith SH-X

2001 2002Year

2003 2004

Next generation

SH-Mobile10.2-mA/MHz core

SH-Mobile20.2-mA/MHzcore

SH-Mobile30.07-mA/MHzcore

SH-Mobile J0.2-mA/MHz core

SH-Mobile V0.2-mA/MHzcore

VGA: video graphic array

Hitachi Review 5

and other middleware deemed essential for cell phones.Furthermore, with the cooperation of many partnermanufacturers, it will be possible to implement evenfaster functions by means of a third-generation engine,embedded Java and other such improvements. We alsoplan to expand compatibility with other operatingsystems.

Embedded JavaTo allow the implementation of diverse

applications, the introduction of embedded Java forcell phones is also becoming common. Whenexecuting Java in cell phones, where it is difficult toincrease the speed of access to external memorybecause of constraints in the mounting board design,the large capacity cache memory of the SH-Mobileprocessor (32 kbytes) is useful. Hitachi, incollaboration with partner manufacturers, isdeveloping a Java engine that makes full use of thatcache memory to achieve a processing speed that is20 times that of conventional cell phones.

CONCLUSIONSWe have described the SH-Mobile Series

application processors developed by Hitachi for usein cell phones.

The SH-Mobile Series first shipped in April of 2002and has been in use by a number of cell phone terminalmakers since that time.

In future development, we plan to further improve

Fig. 6—External Appearance of the SH-Mobile1 SH7290Solution Engine.This development board concentrates various peripheraldevices that are required for a cell phone system, such as anLCD panel, CMOS camera module, key switch and varioustypes of memory devices.

multimedia processing performance by increasing theresolution of the camera interface, introducinghardware acceleration for MPEG-4 and 3-D graphics,and so on. In particular, we will continue to introducevarious kinds of new technology with the SH-Mobile3 chip, which is in development targeting 2004, suchas 0.13-µm process technology and the SH-X, a newlydesigned core for mobile devices.

REFERENCES(1) T. Shindo, “Hitachi’s Cell Phone Offensive,” Nikkei Electronics

5, pp.30-31 (May 2002) in Japanese.(2) T. Yamada et al., “A 133MHz 170mW 10µA Standby

Application Processor for 3G Cellular Phones,” ISSCC Digestof Technical Papers, pp.370-474 (2002).

(3) T. Tsunoda et al., “Application Processor for 3G CellularPhones,” Proc. COOL Chips V, Vol. I, pp.102-111 (Apr. 2002).

ABOUT THE AUTHORS

Toshinobu KanaiJoined Hitachi, Ltd. in 1998, and now works at theSystem Solution Business Unit of the Semiconductor& Integrated Circuits. He is currently engaged in themarketing of the SH-Mobile series and othermicroprocessors for cell phones. Mr. Kanai can bereached by e-mail atkanai-toshinobu@sic.hitachi.co.jp.

Hiroshi YagiJoined Hitachi ULSI Systems Co., Ltd. in 1991, andnow works at the System Solution Business Unit ofthe Semiconductor & Integrated Circuits. He iscurrently engaged in the development of the SH-Mobile series and other microprocessors for cellphones. Mr. Yagi can be reached by e-mail atyagi-hiroshi@sic.hitachi.co.jp.

Junichi NishimotoJoined Hitachi, Ltd. in 1992, and now works at theHardware and Software Technology Division of theSemiconductor & Integrated Circuits. He is currentlyengaged in the development of the SH3-DSP core.Mr. Nishimoto can be reached by e-mail atnishimoto-junichi@sic.hitachi.co.jp.

Ikuya KawasakiJoined Hitachi, Ltd. in 1982, and now works at theSystem Solution Business Unit of the Semiconductor& Integrated Circuits. He is currently engaged in thedevelopment and marketing of the SH-Mobile seriesand other microprocessors for cell phones.Mr. Kawasaki can be reached by e-mail atkawasaki-ikuya@sic.hitachi.co.jp.