Evolution of transportable chip sets of Intel

Evgenie Rudometov

authors@rudometov.com

Correct usage of processors and successful development of their architecture demands adequate chipsets of system logic — chip sets. Implementation of potential possibilities of processors, together with efficiency of their interaction substantially depends on operation of these sets with other units and computer subsystems, that in a finite role defines functionality of computers

Became already an axiom, that key units of computers are their central processor units (further the CPU or it is simple processors). However implementation of considerable potential possibilities of these major accessories depends on their electronic surrounding presented by specialised chips and other radioelements. These components set necessary working conditions of power supplies and transmission of computer data, that is provide correct operation of the CPU. They also carry out electrical and logical links of the processor with other parts of all system, carrying out coordination of their operation and influencing on functionality of computers, aspiring to provide the greatest overall performance of all components. For this reason the given chips quite often name as chips of system logic, and one of the major functions is service of processors.

Intensive development of the architecture of the processors, grounded each time on usage of the newest processing techniques, has generated set of types of these major units. They differ both an inner pattern, and parametres, including features of hooking up. All it has in turn demanded an appropriate variety and perfection of the radio-electronic processor surrounding providing an appropriate infrastructure of maintenance of processors within the limits of the architecture of personal computers (PC).

Estimating PC evolution, it is necessary to mark, that these arrangements any time have been presented by exclusively desktop variants with motherboards. Their basis made set of the chips representing a surrounding of the CPU and defining functions of system logic.

Perfection of semiconducting and computer processing techniques has allowed to raise complexity of accessories. As a result, since some moment, it was possible to create the compact systems, transportable arrangements step-by-step gaining feature.

At the formation initial stage rather laptops have been fulfilled in the form of small small suitcases and briefcases. However further in process of perfection of architectures and processing techniques the truth while there are enough big was possible to finish the computers intended for transportable usage, to the sizes of books and notepads. According to the sizes the first of them have been named leptopami (laptop), the second have made a class of notebooks (notebook). In addition to told it is necessary to mark, that the specified transportable computers in many respects have inherited the architecture of the desktop prototypes, including chips of the system logic which specialised sets have been named by chip sets (chipsets).

Implementation of potential possibilities of processors, together with efficiency of their interaction substantially depends on the co-ordinated operation of these sets with other units and computer subsystems. Therefore specialised chipsets, their inner pattern and functionality should be closely co-ordinated to features of the architecture of concrete variants of processors, with which they are oriented to operation also which should help with implementation of their potential possibilities. Besides, such a set form taking into account various patterns of computers and a possible variety of solved tasks. It is necessary to add, that chip sets represent a basis of motherboards and in many respects define functionality of computer systems.

Usage of optimally designed specialised set is pledge of high efficiency of the computer and on the contrary, application of the nonoptimal chipset of a surrounding of the processor leads to lowering of the common productivity and limitation of functionality of all system of the computer.

Thus, along with release of new processors practically simultaneous engineering of a specialised set of system logic is usually carried out. Without such set the modern processor remains simply a chip, useless, but rather cost-intensive slice of silicon with extremely difficult internal electronic structure presented today already more than one hundred millions of transistors.

There are specialised chipsets of system logic — chip sets — for each generation of processors. Moreover, for each of generations of processors there can be some variants of the chip sets, differing the internal architecture, structure and quantity of chips, and also the corporation-manufacturer, functionality and an overall performance of such specialised set substantially defining parametres of the main subsystems. For this reason so important detailed consideration of structure, parametres and possibilities of the chip sets which analysis is necessary for support of their optimal choice for the purpose of the most adequate correspondence to tasks in view.

The main components of chip sets

Before to pass to the analysis of possibilities of chipsets of system logic, it is necessary to mark, that development of their architecture has allowed to reduce number of chips used in their structure. A basis of modern chip sets now are, with rare exception, only two components.

The first is presented by the chip which has received name North Bridge. This component, by means of the controllers built in it define operation of the cores to computer subsystems, providing link between the processor, dynamic storage units, and for quite some time now and the videoadapter. In addition to it, the given component inspects operation of maps of the extension which are hooked up to North Bridge if, of course, it is provided by the chip set architecture. Besides, one more function is support of link with the second component (or components) a chip set.

This component is the chip named South Bridge. It by means of the built in resources and external units provides the control over operation of the big number of rather slow peripheral devices.

It is necessary to mark, that sharing of chip sets on components allows to develop specialised chips. It provides effective problem solving at the expense of a combination of components.

It is necessary to add, that one of basic functions of chips of chip sets is efficient control resources of computers. The numerous buses which are a part of the architecture of the computer system and streams of the information handled with their help concern these resources, by the way. Besides, considering specificity of transportable systems, chip sets play an active role in handle and saving of the power resources presented by standalone power supplies.

Previous history of chip sets

Considering evolution of chip sets of transportable systems, it is necessary to mark, that Intel corporation is the main manufacturer of chip sets not only for products of this market, but also for sector of desktop systems with which the era of specialised chips has started. And Intel lead here is indisputable, though it is given to it not easily.

However it was far not always. Moreover, some time of Intel at all had no solutions, and desktop computers were gathered on the basis of specialised sets from other corporations.

It is considered, that, generally speaking, the first chip set named (82С206) was offered by Chips and Technologies corporation in 1986 Certainly, this set was not a chip set of transportable systems, moreover, he at all resembled those packages of chips which use today, however on coordination of computer subsystems it fulfilled the elementary functions.

The chip set 82С206 consisted of five chips among which one was the main and four — auxiliary units. It already contained the bus controller, the system clock, the system timer, an interrupt controller, etc . As follows from the name, this chip set has been oriented to the CPU of a class of Intel 286 (i286). Soon this set has been improved and has received name New Enhanced AT. And there were more perfect sets for Intel 386 (i386), Intel 486 (i486) etc ., which evolution has led to modern transportable arrangements.

Estimating development of the architecture of computers, it is necessary to mark, that, transportable computers have appeared even before appearance of chip sets in modern understanding, even in a multicomponent variant with implementation of basic functions in the form of separate chips.

Here it is necessary to mark, that the concept of the transportable computer has been developed by Alan Kejem in 1968 Some positions  standalone models have been realised in 12 kg the computer for NASA in 1979 However have been created essentially later.

Computer Osborne  1 created in 1981 on the basis of processor Z80 without a chip set in modern understanding became one of the first transportable developments  . In the architecture of this computer there were no even hard disks, but there were disk drives on floppy disks in the size 5,25 ". Besides, the miniature display has been presented to constructions on a basis also to the cathode-ray tube.

Fig. 1 Computer Osborne  1

It is necessary to mark, that further the transportable solutions have offered such known corporations, as IBM, Toshiba, Compaq, Apple and others. Some early models have been grounded on processors of the architecture of Intel with support of their operation by appropriate chips.

In the course of perfection of the computer architecture the idea of development and release of specialised chipsets has been picked up after the pioneer chipsetostroenija — the corporation Chips and Technologies corporation such companies as Suntac, Opti, VLSI, UMC, etc. Some products of the given corporations became a basis of the first models of the transportable computers created on the basis of the CPU i286 and i386 and possessing is not seldom powerful, essentially exceeding 5 kg.

In 1994 in the market of chip sets the company of Intel with the successful products which have allowed to become a year later to it the dominating manufacturer of chipsets of system logic, the truth at first for desktop systems has actively declared itself. However, making use of the experience, this company has not missed the chance and with transportable computers in the beginning of their mass release, having created a number of successful transportable chip sets. Further by means of more perfect developments of Intel has fixed the success, and has practically superseded competitors from this segment of the market, aggressively having captured and holding in the subsequent years more than 80 % of size of transportable chip sets.

From desktop to the transportable

The first specialised set from Intel considers a chip set i82350, supporting bus EISA and created for class processors i386DX and i486. However it is necessary to mark, that it had no special success as the given bus has not received distribution. Nevertheless, attempts of release desktop and portable computers in which architecture the given bus used, all the same have been undertaken. However such systems did not become mass, even in the market of desktop solutions that was mirrored in destiny and the chip set 82350.

Chip sets i420TX (1992 ), i420EX (1994  ) and i420ZX (1994 ) became the following chipsets of system logic created under i486    . They though were more successful, but it was difficult to name them as chip sets of transportable arrangements because of features of their architecture, functions and features of maintenance. However, strictly speaking, it is necessary to mark, that at that time any rather compact computers with standalone power supplies were considered as the transportable. As to their architecture usually for a basis took known solutions with accessories of desktop computers. As a result so-called transportable arrangements were heavy enough. However even first, rather imperfect and not so transportable products were rather popular as the weight of 5-10 kg then was not considered excessive and users not too frightened off.

As a matter of fact, break was carried out only after appearance of processors of Intel of Pentium. In a number of the sets oriented to the CPU of the given class, there was, at last, a chip set announced as a transportable set. To them became i430MX (1995 ). As a basis has served, as well as it was possible to expect, a desktop variant i430FX: the CPU — P75 +, dynamic storage — FPM/EDO units with maximum size of 128 Mb at caching only 64 Mb. As a matter of fact, difference of a transportable variant from desktop solution consisted in South Bridge component: in a desktop variant chip PIIX, and in transportable — more perfect and compact MPIIX component used .

But on the present the chip set i430TX became popular. The matter is that this chip set even in a desktop variant has received a number of the important processing techniques from the creators. Among them it is necessary to mark processing technique MMX, povyshajushuju efficiency of processing of stream data (one command and a lot of given) and oriented to multimedia applications. Besides, in a chip set one of the first standards the standard energosberezhenija, received name DPMA (Dynamic Power Management Architecture) is realised. Thanks to the processing techniques grounded on implementation DPMA, the chip set could be used as in desktop, and transportable computers. Result was reduced energopotreblenie, and, therefore, and increase in an operating time of system from the standalone power supply. In addition to the enumerated advantages, it is necessary to mark possibility of usage of units of dynamic storage FPM/EDO/SDRAM, UltraDMA/33 protocol for disk drives, a parallel interface of hooking up of maps of PCI 2.1 extension (parallel operations PCI), serial interface USB with a transfer rate to 12 Mbit/with and other functions. It is necessary to add, that implementation of processing technique ACPI (Advanced Configuration and Power Interface) has made possible fast inclusion of the computer, and also system transition in a mode reduced energopotreblenija in the absence of activity of the user or software units that provided the best in comparison with predecessors of conditions of service. All it promoted popularity of i430TX chipset both in desktop, and in transportable solutions. However, despite all advantages of the given chip set, Intel company was not limited to desktop solution of a set and has specially declared and has released a transportable variant which, as a matter of fact, was the same chip set i430TX. Certainly, this step has been routed against competitors and should stimulate on a plan of implementators production of transportable systems.

Fig. 2. Structure of the computer with a chip set i430TX

Further manufacturers of transportable solutions attempts of usage of chip sets of desktop solutions as it was promoted also by Intel did not stop, releasing chip sets which could be used both in desktop, and in transportable solutions.

As example can serve i440BX, created for processors of Intel of Pentium II. This chip set became the second after i440LX the set of double application supporting video subsystem AGP. Here it is necessary to remind, that before video subsystems were under construction exclusively on the basis of bus PCI. The new standard not only has released bus PCI from the increased streams of the information, but also have provided increase of productivity for a drawing. By the way, this circumstance has found reflexion and in the name of a chip set — Intel 440BX AGPset. As to other essential advantages i440BX became the first chip set which has lifted clock rate to 100 MHz. It, certainly, has provided adequate growth of productivity of the computer system. It is necessary to add, that in a chip set i440BX processing technique QPA (Quard Port Acceleration), providing parallelism of internal operations of operation at the expense of implementation of four-port arbitration of the bus of the processor, graphics bus AGP, bus PCI and the memory bus is supported. Besides, the given chip set officially supported memory EDO/SDRAM to 512 Mb (1 Gbytes in case of register memory), UltraDMA/66 protocol, interface USB, and also ACPI as for desktop, and transportable variants.

The transportable variant i440BX which actually was a clone of a desktop prototype is soon declared also. This step was, as a matter of fact, exclusively marketing course.

Fig. 3. Structure of the computer with a chip set i440BX

Further the simplified variants which have received the name i440ZX with support of clock rate of 66 and 100 MHz on which base formed both desktop and transportable systems have been created .

Considering evolution of chip sets from Intel, it is necessary to pay attention, that at implementation of transportable solutions desktop variants, even in case of the declaration of transportable models of chip sets not seldom used. As a rule, it became for economic reasons. However would be an error to consider, that all transportable chipsets of system logic of that time were exclusively clones of the desktop clones. As an example of the separate development which are not duplicating a desktop prototype, it is possible to result a chip set i440MX. This variant created on a basis i440BX, represented odnochipovyj a variant oriented exclusively on the transportable market.

Fig. 4. Structure of the computer with a chip set i440MX

The given chip set has been oriented to support of transportable processors of Intel Celeron with the architecture of kernel P6, as well as for processors of Intel of Pentium II and Intel of Pentium III. And as it was announced, as an inner pattern basis i440MX and South Bridge a chip set i440BX with saving chips North Bridge have served in advanced design of all functions of its prototype. As an exception the video subsystem which in a new chip set is presented by solutions on the basis of PCI unlike a prototype where as a video subsystem basis port AGP has served has served.

It has been created two variants: i440MX and i440MX-100, differing clock rate of the bus of memory. It is necessary to add, that for i440MX odnochipovogo the clone among desktop solutions was not. It favourably distinguished a transportable variant from a prototype and allowed to lower a system total price essentially.

Considering the architecture and possibilities of this solution, it is necessary to mark, that from the moment of its appearance of a line of chip sets for desktop and transportable systems began to disperse in increasing frequency. It is linked, first of all, to the requirements imposed by processors, oriented to different segments of the market and projected differently. It is linked first of all by that the purposes facing to implementators of desktop and transportable systems, step-by-step began to vary. If for desktop solutions the main thing is a productivity for transportable computers on the first place parametres linked to maintenance from which the major are the weight and profitability energopitanija began to quit. Really, the weight substantially defines portability, and energoekonomichnost systems along with secondary generator size — time of offline work of the transportable arrangement. For this reason transportable processors began to project counting upon reduced power supplies, and support functions laid down on appropriate chip sets.

The set i815EM, supporting clock rate of the processor bus to 100 MHz and oriented to transportable variants of processors became one of such chip sets . Transportable Intels of Pentium III – M and Intel Celeron became such variants . The chip set i815EM has received a wide circulation for the systems constructed on the basis of given processors. Created on the debugged base of processing techniques i440BX, i815EM chipset possesses a number of characteristics of a new generation. First of all, it is the video resources built in its structure. I815EM chipset allowed to instal in addition 4 Mb of the display cache memory, or to use external graphics controller AGP4X for improvement of quality of video maps and an expedition of output of a three-dimensional drawing.

I815EM chipset consists of two chips named as implementators by hubs (controllers-hubs).

The first of chips of the given set is a traditional, standard component which realises link with the processor, a dynamic storage subsystem, a video subsystem and the second component.

The second component of the given chip set is responsible for input/conclusion. It has name ICH2-M, has intrinsic functions LAN and four ports USB, controller AC ’ 97 (supports completely a volume 6-channel sound and operation of the programs realising functions of the modem), etc. Besides, chip ICH2-M, created for transportable systems, supports processing technique of Intel SpeedStep. The given processing technique carries out automatic switching of the processor between two main clock rates depending on load on the processor that provides optimisation of an operating time from batteries and productivity of applications. It provides the raised operating time in a local mode from the transportable computer of the internal power supply built in structure. Further the processing technique of Intel SpeedStep was exposed to numerous refinement.

Following transportable chip set became i830. Created on the basis of the predecessor — i815EM, it is oriented to systems with transportable Intels of Pentium III-M and Intel Celeron. This chip set has clock rate of the bus of the processor to 133 MHz and supports dynamic storage PC133 SDRAM units.

Here it is necessary to remind, that by this time transportable processors have successfully passed from nozhevogo (SECC plug to standard, so-called soketnomu (Socket). Processors have been released in tanks of two types - MicroFCPGA (Flip Chip Pin Grid Array) and MicroFCBGA (Flip Chip Ball Grid Array), approaching even for the smallest subnotebooks and tablet PCs. For these arrangements models with low and ultralow energopotrebleniem, reached at the expense of a power supply reduced voltage (LV — Low Voltage and ULV — Ultra Low Voltage) and the reduced frequency of operation of a kernel have been released  . As a result by operation from batteries the processor of Intel of Pentium III - M (866 МГц/533 the MHz) consumes less than 1 W. The model of the processor with an ultralow supply voltage (700 МГц/350 MHz) in a functional mode from batteries consumes 0,5 W. Such levels energopotreblenija allow to create mini-and subnotebooks with time of offline work more than 7 hours. However wide functionality of standard and economic variants of Intel of Pentium III - M demands an appropriate surrounding. As the central unit of microcircuit support of the processor the chip set i830 has appeared.

The chip set i830 has three versions of implementation of the controller of memory. The first modification is the i830MP chipset supporting external graphics adapter AGP 2X/4X. The second modification is i830M chipset with the built in graphics controller; this modification allows to use and an external graphics adapter. At last, the third modification is i830MG chipset with the built in inexpensive graphics subsystem for a segment of inexpensive solutions of the market of transportable computers.

From key features i830 it is necessary to mark support of memory to 1 Gbytes, six ports USB and the modes improved in comparison with predecessors energosberezhenija, that allows to increase even more an operating time of transportable systems from the built in electric power supply.

Summing up to the analysis of possibilities of transportable chipsets of system logic of i830 set, it is necessary to mark, that development of the given architecture has received the logical continuation in a chip set i845.

The set of transportable i845 chipsets includes two variants of chips: i845MP, created for efficient systems, and i845MZ for systems of initial level. Both chipsets are developed, tested and optimised for operation with the transportable processor of the architecture new to transportable systems. This architecture known from desktop solutions as NetBurst, has replaced previous generation P6, in transportable sector completed development in appropriate models of Intel of Pentium III-M and Intel Celeron. More perfect models of transportable processors have received the name, by the way, similar to the high-powered desktop clones, — Intel of Pentium 4 - M.

The set of i845MP/i845MZ chipsets (the memory controller-hub 82845MP/82845MZ) supports external graphics solution AGP 4X and the processor bus inherited from a desktop prototype.

For the transportable solutions created on the basis of specified variants of this set, given bus FSB of type QPB (Quad-Pumped Bus) works on clock rate of 100 MHz. As is known bus FSB of type QPB at clock rate of 100 MHz carries out data transfer with frequency of 400 MHz, an address part — 200 MHz that capacity to 3,2 Gbytes/with provides peak .

Besides, the chip set i845MP provides support of units of dynamic storage of type DDR 200 and DDR 266 SDRAM by total amount to 1 Gbytes, and a chip set i845MZ — only DDR 200 SDRAM in total amount to 512 Gbytes.

Considering possibilities of a subsystem of memory, it is necessary to remind, that memory DDR SDRAM (Double Data Rate SDRAM) — is memory SDRAM providing data transfer on lobbies and back edges of clock pulses of the bus of memory, that is works actually on the doubled clock rate. It means, that new memory — DDR 200 and DD R266 possesses the doubled pass-band (provides data transfer twice more for a time unit) in comparison with earlier used type SDRSDRAM (Single Data Rate SDRAM or it is simple — SDRAM), presented in transportable systems of the previous generation PC100 units and PC133 SDRAM. Usage in transportable systems of new type of memory has provided essential growth of productivity.

The set of i845MP/i845MZ chipsets also supports advanced processing technique of Intel SpeedStep, modes Deep and Deeper Sleep reduced energopotreblenija, providing reliable transition between various states energopotreblenija.

The advanced processing technique of Intel SpeedStep dynamically changes clock rate and a supply voltage of the processor depending on necessary computational capability. For example, power consumption of the processor of Intel of Pentium 4 - M on the average makes 2 W thanks to that the processor supply voltage decreases to the value less than 1 V.Eto occurs, for example, during the periods between blows on keyboard keys. However when maximum productivity is necessary, the kernel supply voltage raises to 1,3 V.Takoe dynamic switching of a divider of clock rates of buses, supply voltages of a kernel and clock rate of a kernel are increased considerably by an operating time from batteries.

One more approach applied in transportable units and systems supporting their operation, created on the basis of appropriate chip sets, are special controls energopotrebleniem, such as processing technique Deeper Sleep. In state Deeper Sleep the processor supply voltage decreases to the least possible level at which there is no loss of data. It is obvious, that in the given mode the power consumption of batteries is essentially reduced.

All these modifications of modes of optimum control by modes energopotreblenija, supported by a chip set i845, allow to combine high efficiency with rather durable period of offline work, that together with compactness and rather low weight are key parametres of transportable computers.

As to possibilities of handle of input/output arrangements they are defined by the second component of a chip set i845 in which base package uses ICH3-M that provides UltraATA/100, PCI, LAN, USB, AC ’ 97 2.2, etc.

The improved variant of chip sets i845 are the chip sets of i852 set optimised under models of the transportable processor of Intel of Pentium 4 - M. These chip sets are presented by three variants: i852GME, i852GM, i852PM.

The first most powerful variant of a chip set has the built in graphics resources and provides support of external AGP 4X videoadapter. Supports the processor bus with a transmission frequency of data of 533 and 400 MHz, units of dynamic storage of type DDR 333/266, size to 2 Gbytes.

Fig. 5. Structure of the computer with a chip set i852GME

The second variant of a chip set has the built in graphics resources and does not provide support of the external videoadapter. Supports the processor bus with frequency of 400 MHz, memory of type DDR 200/266, size to 1 Gbytes.

The third variant of a chip set has built in graphics no resource, but provides support of external AGP 4X videoadapter. Supports the processor bus with frequency of 533 and 400 MHz, memory memory of type DDR 333/266, size to 2 Gbytes.

All variants support 6 ports USB, UltraDMA/100, etc., and also processing techniques energosberezhenija. These processing techniques concern Enhanced Intel SpeedStep — processing technique a supply variation and the frequencies of the processor covering modes from level of maximum productivity, to an economy effort of energy for prolongation of operation of secondary generators. Wait state Deeper Sleep Alert is besides, supported — the mode of dynamic handle of power supplies functions at a smaller supply voltage, than mode Deep Sleep. All it increases life expectancy of batteries and accordingly raises level of mobility of portable systems.

However, despite efficiency of the used solutions created on the basis of Intel of Pentium 4 – M and i852 set chip sets, experts of Intel have continued operation over perfection of the architecture of the major computer components.

These efforts have not gone to waste and have found incarnation in transportable models of the processor of the new architecture, and also in appropriate transportable chip sets.

But about it in the following part of article.

In article open substances of corporation of Intel are used