Power Connector and Voltage Regulator

Power Connectors:-

     
                The motherboard has a socket to attach the power cables coming from the power supply. ATX form factor motherboards  and power supplies use a single 20-wire motherboard power cable. All others use a pair or 6-wire cables.

                     The cables are connected to the motherboard so that the black wires are together in the middle. This connector is usually found near the back right-hand side of the motherboard, near the power supply.

Voltage Regulators:-

       In old days, devices used to run on same voltage of 5V. The arrival if processors and other devices  running at different voltages led to the necessity of motherboards. These regulators reduce the 5V signal to those voltages typically needed by processors: 3.3V or lower.

        Processor manufacturers fit in a dual voltage scheme into their latest designs. The processor is fed two voltages: the external or "I/O" voltage is typically 3.3V, while the internal or "core" voltage is lower: usually 2.8 to 3.2 volts. The voltage regulator is responsible for generating the correct voltage for the processor.

       The voltage regulator can normally be identified by the large heat-sinks that are placed on it; Voltage conversion generates a great deal of heat. On many motherboards, the cooling level of the entire system case is important to ensure that the voltage regulators are cooled satisfactorily. Overheating regulators can cause lockups and other problems.

Motherboard Components(Bus)

Why Bus:-
           A personal computer may transfer data from disk to CPU, from CPU to memory, or from memory to the display adapter. A PC cannot afford to have separate circuits between every pair of devices. A mechanical switch, like the old phone systems used, would be too slow. So we can use bus.

Bus:-
         

              The Bus is simply a common set of wires that connect all the computer devices and chips together. (or) A bus is a common pathway across which data can travel within the computer. This pathway is used for communication and can be established between two or more computer elements. A PC has many kinds of buses, including the following:

•  Processor bus
•  Address bus
•  I/O bus
•  Memory bus

Processor Bus:-
         The processor bus is a communication pathway between the CPU and immediate support chips. These support chips are usually called the chipset in modern systems. This bus is used to transfer data between the CPU and the main system bus.

Address Bus:-
        The address bus actually is a subset of the processor and memory buses. It is used to indicate what address in memory or what address on the system bus are to be used in a data transfer operation.
The size of the memory bus also controls the amount of memory that the CPU can address directly.

Memory Bus:-
        The memory bus is used to transfer information between the CPU and main memory(RAM)  in your system. This bus is either a part of the processor bus itself, or in most cases it is implemented separately by a dedicated chipset that is responsible for transferring information between the processor bus and the memory bus.

I/O Bus:-
       All the motherboards have one or more system I/O buses that are used to expand the computer's capabilities. These buses work closely with expansion cards. The slots in the back of the machine are where expansion cards are placed. These slots allow you to expand the capabilities of your machine in many different ways, and the proliferation of both general purpose and very specific expansion cards is part of the success story of the PC platform.

         Most modern PCs have two different types of bus slots. The first is the standard ISA (Industry Standard Architecture) slot; most PCs have 3 or 4 of these. These slots have two connected sections and start about a half-inch from the back of the motherboard, extending to around its middle. This is the oldest  bus type and is used for cards that don't require a lot of speed: for example, sound cards and modems. Older systems may have ISA slots with only a single connector piece on each; these are 8-bit ISA slots and will only support 8-bit ISA cards.

Motherboard components

Motherboard components:-

         There are many components, which is placed in motherboard. The following are the most important components of motherboard.

 ROM:-
             
              All motherboards include a small block of Read Only Memory (ROM)  which is different from the main system memory used for loading and running software. The ROM contains the PC's Basic Input/Output System(BIOS). This offers two advantages: the code and data in the ROM BIOS need not be reloaded each time the computer is started, and they cannot be corrupted by wayward applications that write into the wrong part of memory.

              A Flash upgrade-able BIOS may be updated via a floppy diskette to ensure future compatibility  with new chips, add-on cards, etc.

BIOS:-

          BIOS (Basic Input/Output System), is also known as ROM BIOS, or System BIOS. It is a chip located on all motherboards that contain instructions and setup for how your system should boot and how it operates. 

            The BIOS includes instructions on how to load basic computer hardware and includes a test referred to as a POST (Power On Self Test) that helps verify the computer meets requirements to boot up properly. If the computer does not pass the POST, you will receive a combination of beeps indicating what is malfunctioning within the computer.

Four main functions of BIOS:-

POST:-
          
          Test the computer hardware and make sure no errors exist before loading the operating system.                  Additional information on the POST can be found on our POST and Beep Codes page.

Bootstrap Loader:-
          
          Locate the operating system. If a capable operating system is located, the BIOS will pass control to it.

BIOS drivers:-
          
           Low level drivers that give the computer basic operational control over your computer's hardware.

BIOS or CMOS Setup:- 

           Configuration program that allows you to configure hardware settings including system settings such as computer passwords, time, and date.

Processor Sockets or Slots:-

             The motherboard has one or more sockets or slots to hold the processor. Single processor motherboards are by far the most common, but dual processor boards are not hard to find. The type of socket or slot used dictates the type of processor that can be used by the motherboard. Not surprisingly, the standards for processor socket and slot have been generally defined by Intel ( a leading company in designing and manufacturing processors and motherboards). 

             Older Intel processors, up to the Pentium Pro, use a square shaped socket for the processor . The latest processors from Intel, starting with the Pentium  II, are mounted on a daughter-board, which plugs into a special type slot, known as SEC(Single Edge Connector) slot, to connect to the motherboard.

Memory Socket:-

              Most motherboards today come with between 2 and 8 sockets for the insertion of memory. These are usually either SIMMs(Single Inline Memory Modules) or DIMMs(Dual Inline Memory Modules). These sockets can be of different sizes.

                The motherboard usually labels these sockets "SIMM0" through "SIMM7" or "DIMM1" through "DIMM3", etc. The sockets are almost always filled starting with the lowest numbered socket first. Most Pentium class or higher motherboards require SIMMs to be inserted in pairs, but DIMMs may be inserted individually.

Cache and/or cache Sockets:-

                Cache is a high-speed access area that can be either a reserved section of main memory or a storage device. Virtually all newer Pentium class motherboards come with either integrated secondary cache or sockets for secondary cache to be inserted. Also called "Level 2" or "L2" cache, secondary cache is high speed memory that is used to buffer processor requests to the regular system memory.

                  256 KB or 512 KB of cache is most common. 1MB and higher cache are now available in the market. Motherboards for Pentium Pro and Pentium II PCs don't have level 2 cache on them; it is already integrated into the processor itself for the Pentium Pro, and into the processor package for the Pentium II.

Introduction to motherboard

Motherboard:-

              The motherboard (also known as  mainboard, system board, planar board or logic board, or colloquially, a mobo) is the main circuit board inside the PC. It holds the processor, memory and expansion slots and connects directly or indirectly to every part of the PC. It's made up of a chipset, some code in ROM and the various interconnections or buses.

              PC designs today use many different buses to link their various components. Wide, high-speed buses are difficult and expensive to produce: the signals travel at such a rate that even distances of just a few centimeters cause timing problems, while the metal tracks on the circuit board act as miniature radio antennae, transmitting electromagnetic noise that introduces interference with signals elsewhere in the system.

               For these reasons, PC design engineers try to keep the fastest buses confined to the smallest area of the motherboard and use slower, more robust buses, for other parts.

                  A motherboard is the main printed circuit board (PCB) found in computers and other expandable systems. It holds many of the crucial electronic components of the system, such as the central processing unit (CPU) andmemory, and provides connectors for other peripherals. Unlike a backplane, a motherboard contains significant sub-systems such as the CPU.

               

                Motherboard specifically refers to a PCB with expansion capability - the board is the "mother" of all components attached to it, which often include sound cards, video cards, network cards, hard drives or other forms of persistent storage, TV tuner cards, cards providing extra USB or Firewire slots, and a variety of other custom components.

Design for motherboard:-

                A motherboard provides the electrical connections by which the other components of the system communicate. Unlike a backplane, it also connects the central processing unit and hosts other subsystems and devices.

              A typical desktop computer has its microprocessor, main memory, and other essential components connected to the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices may be attached to the motherboard as plug-in cards or via cables, in  modern        

computers it is increasingly common to integrate some of these peripherals into the motherboard itself.

             An important component of a motherboard is the microprocessor's supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard.      

C programing style

Programming style:-

•       C is a free form language.

•       Write the program in lowercase letters. C program statements are written in lower case letters. Uppercase letters are used only for symbolic constants.

•       Braces ({&}) groups program statement together and mark the beginning the end of function.

•       A proper indentation of braces and statements would make a program easier to read and debug.

•       Since C is a free-form language, we can group statements together on one line.

• The statements:

                           a=b;
                           x=y+1;
                           z=a+x;
               
                      can be written on one line as a=b; x=y+1; z=a+x;

• In the program:

                       main()
                      {
                                printf("Hello C");
                         }
                       can be written in one line as

                               main() { printf("Hello C"); }

•         This style makes the program more difficult to understand and should not be used

Features of C Language

Features or Advantage of C:-

• C is a structured programming language. The objective of a structured programming is to provide methodology in which, the user may develop programs quickly with less mistakes.

• Further, it increases the readability of the program and finally the flexibility of the program is improved to the maximum, which helps the programmer to modify the program without affecting the other portion of the program.

• It is a disciplined approach towards the programming that promotes clear, efficient and error-free programming.

• The structures such as sequence, condition and loop structure are incorporated in the C programming language.

• These structures help the programmer to avoid the undesirable statement called 'goto' statement. The 'goto' statement is an unconditional statement which leads to unstructured programming.

• C is a case-sensitive language i.e C recognizes uppercase and lowercase characters separately. For example, declaring the variable by the name 'add'  is different from 'ADD' or 'Add'. All the three variables are different and unique. Case-sensitiveness leads to a rich character set.

• Portability

• Implemented on many diverse systems
• Implemented on wide variety of hardware
• Defined libraries are themselves portable
• Applications are portable
• Programs are portable

• Powerful
• Completeness – business to scientific applications
• Flexibility – preprocessor, conditional compilation, header files

• C can reference a memory location by means of its address with the help of pointers and allows the user for manipulating Bits(Binary Digits).

• Every statement in the C program should necessarily end with a semicolon. This character is called as the statement delimiter.

Introduction about C Programming

The Art of Programming:-

•             Programming is the technique of defining logic for solving a particular problem. The logic is explained by a series of statements that are usually executed one after other. 

•             The primary objective for writing a program to achieve the desired output. The programmer should first understand what output should he/she produce and how the information should be placed in the output screen.

•             Secondly, the programmer should identify the various inputs that are supplied for obtaining the output.

•             Thirdly, the programmer should take into consideration the constraints or conditions, which affect the output of the program.

C Programming:-

•     C is a general purpose programming language and which is initially developed by Dennis Ritchie in the year of 1972 at AT& BELL laboratories. 

•    It is a structured programming language. C is called a middle-level language( a third term which is a combination of High level and Low level language) because C possess the features of the second and third generation languages.

• C is a highly portable language, that is, a C source program written on one computer can be compiled and executed  on a different computer with less or no modification in the source code.

•  It can be viewed as group of building blocks called functions.

• A function is a subroutine that may includes one or more statements designed to perform specific task. To write a C program, we first create functions and then put them together.

• C is a powerful language. Comments in C provides easy readability.

                     The following diagram will show the overview of C Program:-

Documentation section

Link section

Definition section

Global declaration section

Main ( ) function section  {                     Declaration part                     Executable part }

Subprogram section { Function_1( ) {   } Function_2() {  } }

             

              A C program may contain one or more section . The following topics will give the details about the sections in the C Program.

Documentation section:- 

                

          Documentation section consists of a set of comment line giving the name of the program, the author and other details, which the programmer would like to use later.

Link section:-

         The link section will provide instructions to the compiler to link functions from the system library. The definition section defines all symbolic constants.

Global Declaration section:-

         There are some variable that are used in more than one function. Such a variable are called global variable and are declared in the global declaration section that is outside of all functions.

        This section also declares all the user defined functions.              

Main Function Section:-

        Every C program must have one main () function section. This section contains two parts. They are:

•        Declaration part
•        Executable part

Declaration part:-

        In the declaration part declare all the variables used in the executable part. There is at least one statement in the executable part.

         These two parts must appear between the opening  and closing brace. The closing brace of main function section is the logical end of the program. All statements in declaration and executable part end with semicolon. 

Sub program section:-

         It contains all the user-defined functions that are called in the main function. User defined functions are generally placed immediately after the main function, although they appear in any order. All sections other than main function are optional.