Introduction Part 1 The Microprocessor Based Systems  Memory and I/O System  Microprocessor

Microprocessor I/O System Memory System Buses Dynamic RAM (DRAM) Static RAM Cache Read-Only (ROM) Flash Memory EEPROM SDRAM RAMBVS Pentium Pentium Pro Pentium II Pentium III Pentium 4 Printer Serial Communications Floppy Disk Drive Hard Disk Drive Mouse CD-ROM Drive Plotter Keyboard Monitor Tape Backup Scanner DVD The Block Diagram of a Microprocessor- Based Computer System

The Memory Map of Personal Computers 15M bytes in the or 80386X 31M bytes in the 80386SL/SLC 63M bytes in the 80386EX 4095M bytes in the 80386DX, 80486, and Pentium 64G bytes in the Pentium Pro, Pentium II, Pentium III, and Pentium 4 1M bytes of real (conventional) Memory System Area 384K bytes TPA 640K bytes Extended Memory The transient program area (TPA) holds the DOS operating system and other programs that control the computer system. The TPA also stores any currently active or inactive DOS application programs.

The Memory Map of the TPA in a Personal Computer (vary between systems) COMMAND.COM Free TPA Device drivers Such as MOUSE.SYS IO.SYS program BIOS communications area MSDOS program DOS communications area Interrupt vectors MSDOS program E30 9FFF0 9FFFF The Interrupt vectors access various features of the DOS, BIOS (basic I/O system), and applications. The System BIOS and DOS communication areas contain transient data used by programs to access I/O devices and the internal features of the computer system. The IO.SYS is a program that loads into the TPA from the disk whenever an MSDOS or PCDOS system is started. It contains programs that allow DOS to use the keyboard, video display, printer, and other I/O devices often found in the computer system. The I/O.SYS program links DOS to the Programs stored on the system BIOS ROM. DOS occupies two areas of memory: One is 16 bytes in length and is located at the top of the TPA, and the other is much larger and is located near the bottom of the TPA. The DOS program controls the operation of the computer system. The size of the DOS area depends on the version of DOS installed in the computer and how it is installed

The Memory Map of the TPA in a Personal Computer (vary between systems) COMMAND.COM Free TPA Device drivers Such as MOUSE.SYS IO.SYS program BIOS communications area MSDOS program DOS communications area Interrupt vectors MSDOS program E30 9FFF0 9FFFF The size of the driver area and number of drivers change from one computer to another. Drivers are programs that control installable I/O devices such as a mouse, scanner, CD-ROM, … The COMMAND.COM program (command processor) controls the operation of the computer from the keyboard when operated in the DOS mode. The COMMAND.COM program processes the DOS commands as they are typed from the keyboard. The free TPA area holds DOS application programs as they are executed. These application programs include word processors, spreadsheet programs, …etc.TPA also holds TSR (terminate and stay resident) programs that remain in memory in an inactive state until activated by a hot-key sequence or another event such as an interrupt.

The Memory Map of the System Area in a Personal Computer (vary between systems) Basic Language ROM (only on new PCS) Video RAM (text area) Video RAM (graphics area) BIOS System ROM A0000 B0000 C0000 Free Area Hard Disk Controller ROM LAN Controller ROM C8000 F0000 Video BIOS ROM E0000 FFFFF

Memory Hierarchy Registers L1 Cache L2 Cache Main Memory Smaller, Faster, and More Expensive Larger, Slower, and Cheaper

The Microprocessor The microprocessor (sometimes referred as the CPU) is the controlling element in a computer system. The microprocessor controls memory and I/O through a series of connections called buses. The microprocessor performs three main tasks for the computer system:  Data transfer between itself and the memory or I/O systems.  Simple arithmetic and logic operations.  Program flow via simple decisions. The power of the microprocessor is in its capability to execute hundreds of millions of instructions per second from a program or software (group of instructions) stored in the memory system.

Arithmetic and Logic Operations Executed by Intel Family of Microprocessors OperationComment Addition Subtraction Multiplication Division ANDLogical Multiplication ORLogical Addition NOTLogical Inversion NEGArithmetic Inversion Shift Rotate DecisionComment Zero Test a number for zero or not- zero Sign Test a number for positive or negative Carry Test for a carry after addition or a borrow after subtraction Parity Test a number for an even or an odd number of ones Overflow Test for an overflow that indicates an invalid signed result after addition or subtraction Decision-making capabilities of the Intel Family of Microprocessors

Buses A bus is a common group of wires that interconnect components in a computer system. The buses transfer address, data, and control information between the microprocessor and its memory and I/O systems. The buses:  Select an I/O or memory device.  Transfer data between an I/O device or memory and the microprocessor.  Controls the I/O and memory system through instructions that are stored in the memory and executed by the microprocessor.

µp MWTC MRDC IOWC IORC Read-only memory ROM Read-only memory ROM Read/write memory RAM Read/write memory RAM Keyboard Printer Address Bus Data Bus Control Bus Requests a memory location from the memory or an I/O location from the I/O devices. Transfers information between the microprocessor and its memory and I/O address space. Contains lines that select the memory or I/O and cause them to perform a read or write operation.

Intel Microprocessors Microprocessor Data Bus Width Address Bus Width Memory Size M M M M M 80386SX162416M 80386DX32 4G 80386EX162664M G Pentium64324G Pentium OverDrive32 4G Pentium Pro64324G Pentium Pro643664G Pentium II64324G Pentium II, Pentium III, Pentium G The memory size depends on the address bus width, for example 20bit address bus means that the processor can address memory size up to 2^20= byte /1024  1024 KB (1MB)