Lecture note on microprocessor and microcontroller theory. The 4004 processor was introduced on november 15, 1971, and originally ran at a clock speed of 108khz 108,000 cycles per second, or just over onetenth a megahertz. Eight of the registers are known as general purpose registers i. General purpose registers are used to store temporary data within the microprocessor. Toshibas t3190 and those of 16bit ps intels 8086, fairchilds 9440, texas. It is a silicon chip that comprises millions of transistors and other electronic components that process millions of instructions per second. The program counter pc, commonly called the instruction pointer ip in intel x86 microprocessors, and sometimes called the instruction address register, or just part of the instruction sequencer in some computers, is a processor register. Registers are temporary storage locations inside the cpu that hold data and addresses. Before knowing about the 8085 architecture in detail, lets us briefly discuss about the basic features of 8085 processor 8085 microprocessor is an 8bit microprocessor with a 40 pin dual in line package. One of the methods of improving microprocessor performance is by parallelism method 22.
It is of 16 bits and is divided into two 8bit registers ah and al. A processor register cpu register is one of a small set of data holding places that are part of the computer processor. The data register on the lm3s8962 is referred to as the gpiodata register. A processor register is a quickly accessible location available to a computers central processing unit cpu. The birth of the microprocessor, the first microcomputers, a leading role for the microprocessor, the promise of reduced instruction set computer risc, and microprocessors of the 1990s. A memory module consists of a set of locations, defined by sequentially. After arithmetic or logical operation, if the result has an even.
Flag register of 8086 microprocessor geeksforgeeks. An index register is a circuit that receives, stores, and outputs instruction changing codes in a computer. There are 8 general purpose registers in 8086 microprocessor. Within the processor, there is a set of registers that provide a level of memory that is. All of the msp430 cpu registers can be used with all instructions. Chapter 4 register transfer and microoperations section 4. Different cpus may only support certain ways of specifying where the data comes from, so the list below should be treated as a set of possibilities.
Microprocessor designregister file wikibooks, open books for an. Microprocessor 2 marks questions and answers uniti 1. Additional registers, called segment registers, generate memory addresses when combined with other registers in the microprocessor. Register are used to quickly accept, store, and transfer data and instructions that are being used immediately by the cpu, there are various types of registers those are used for various purpose. Cs code the code segment is a section of memory that holds the code used by the microprocessor. It determines the number of operations per second the processor can perform. It keeps track of the the next memory address of the instruction. On these lines the cpu sends out the address of the memory location that is to be written to or read from.
The time tcy in the above figure is called as the machine cycle. Microprocessors were first introduced in early 1970s. Again, the number and types of operations define the. Among of the some mostly used registers named as ac or accumulator, data register or dr, the ar or address register, program counter pc, memory data register mdr,index register,memory buffer. Cse 307 microprocessor passing data to a subroutine data is passed to a subroutine through registers. Architectural register the registers visible to software defined by an architecture. Later microprocessors 8086 and 68000 were designed with. Register is one of a small set of data holding places that are part of a cpu registers are. Intel 80868088 microprocessor it is an intel microprocessor and also a 16 bit microprocessor. This instruction set defines what the microprocessor can. A microprocessor is a versatile chip, that is combined with memory and specialpurpose chips and preprogrammed by a software. A processor with longer word length is more powerful and can process data at a faster speed as compared to. The basic units or blocks of a microprocessor are alu, an array of registers and control unit.
To demonstrate the function and use of the registers on a microcontroller, the implementation on the 8962 will be used as an example. The parallelism is the concept of using duplicated hardware to fasten the execution of a program. The 8085 includes six registers, one accumulator and one flag register, as shown in fig. The intel 8088 was a version with an eightbit external data bus.
Microprocessor picks up data from one of the registers for doing arithmetic or logical operation. A number of registers are normally included in the microprocessor. Microcomputer a computer with a microprocessor as its cpu. The data comes in one after the other per clock cycle and can either be shifted and replaced or be read off at each output. Microprocessor a cpu built into a single chip is called microprocessor. The intel 8086 was based on the design of the intel 8080 and intel 8085 it was source compatible with the 8080 with a similar register set, but was expanded to 16 bits. The address and data bus are multiplexed in this processor which helps in providing more control signals. Microprocessor is the brain of computer, which does all the work. Microprocessor types and specifications page 2 of 158 file.
In any cpu, most instructions operate on data, and that data can usually come from several places. After the controller family has been selected, the next step is to choose the right controller for the job see ber02 for a more indepth discussion on selecting a controller. Similarly the resultant data will be loaded from registers to memory. It contains arithmetic and logic unit alu, instruction decode and control unit, instruction register, program counter pc, clock circuit internal or external, reset circuit internal or external and registers. The register file is the component that contains all the general purpose registers of the microprocessor. It is the number of bits processed in a single instruction. Following is a list of each segment register, along with its function in the system. The flag register is a special purpose register and it is completely different from other registers in. The beginning of the stack is defined by loading 16bit. The data is stored in one of the registers by the calling program and the subroutine uses the value from the register. A microprocessor is a component that performs the instructions and tasks involved in computer processing. An 8bit microprocessor can process 8 bit data at a time. This microprocessor exhibits some unique characteristics and this is the reason it still holds popularity among the microprocessors basically, 8085 was the first commercially successful microprocessor by intel.
It means that its alu, internal register and most of the instructions are designed so that these can work on the 16 bit memory word. The address bus consists of 16, 20, 24, or more parallel signal lines. Various functions performed by cpu are explained in the text. Registers computer architecture tutorial studytonight. A few cpus also place special registers such as the pc. Microprocessor definition, an integrated computer circuit that performs all the functions of a cpu. The instruction register ir in a simple microprocessor is a simple register with. Once the operation is over, it stores the result in a register. In computer architecture, registers are typically addressed by mechanisms other than main memory, but may in some cases be assigned. The 80386 processor dramatically extended the 8086 register set.
Microprocessor 8086 article about microprocessor 8086 by. The second type of shift register we will be considering is the serial in parallel out shift register. Registers in computer architecture register is a very fast computer memory, used to store datainstruction inexecution. The 8086 was introduced in 1978 as a fully 16bit extension of intels 8bit 8080 microprocessor, with memory segmentation as a solution for addressing more memory than can be covered by a plain 16bit address. A register is a group of flipflops with each flipflop capable of storing one bit of information.
The basic microprocessor operation such as reading a byte from io port or writing a byte to memory is called as machine cycle. The 8085 has six generalpurpose registers to store 8bit data. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be readonly or writeonly. In other words, microprocessor isan integrated circuit that contains all the functions of a central processing unit of a computer. The register values get modified within the subroutine. The 80858080aprogramming model includes six registers, one accumulator, and. Depending upon the value of result after any arithmetic and logical operation the flag bits become set 1 or reset 0. For example, 8086 microprocessor has 16bit registers and therefore word size of 16bit and can work on 16bit data at a time 16 19. It depends upon the width of internal data bus, registers, alu etc. Intel 8086 processor a sixteen bit microprocessor chip used in early ibm pcs.
What are the standard data word lengths for which microprocessors have been developed. In a computer system, the microprocessor is the central unit that executes and manages the logical instructions passed to it. A processor register is a quickly accessible location available to a computers processors. Chapter 9 stack and subroutines ahsanullah university of. The history of the microprocessor can be divided into five stages. The microprocessor is nothing but the cpu and it is an essential component of the computer. Tutorial on introduction to 8085 architecture and programming halt. Some registers are used internally and cannot be accessed outside the processor, while. A register is a temporary storage area built into a cpu. As some of the architectural drawbacks associated with 8080 was also. A microprocessor is designed to perform arithmetic and logic operations that make use of small numberholding areas called registers. Pdf microprocessor 2 marks questions and answers uniti.
Registers of 8085 microprocessor a microprocessor is a multipurpose, programmable, clockdriven, registerbased electronic device that reads binary instructions from a storage device called memory, accepts binary data as input and processes data according to those instructions and provide results as output. It is a 16 bit special function register in the 8085 microprocessor. Unit1 introduction to 8086 ece department microprocessors and microcontrollers page 2 iv address bus. Parity is define d by the number of ones present in the. These types of shift registers are used for the conversion of data from serial to parallel. Components for microprocessor programming ice incircuit emulator flash emulation tool fet jtag spybiwire 2wire jtag bootloader rewrite flash via rs232 password protected ide integrated development environment editor, compiler, debugger libraries for each microprocessor. Evolution of microprocessor types and applications. A microprocessor may also be called a processor or central processing unit, but it is actually. The first four registers are sometimes referred to as data registers. Registers of 8085 microprocessor a microprocessor is a multipurpose, programmable, clockdriven, registerbased electronic device that reads binary instructions from a storage device called memory, accepts binary data as input and processes data a. This definition explains what a processor register, also known as a cpu register or central processing unit register, is and what it does. Pparity flag parity is defined by the number of ones present in the accumulator. One complete cycle of clock is called as tstate as shown in the above figure.
The 80858080aprogramming model includes six registers, one accumulator, and one flag register, as. This circuit is also called an address register or a register of modifications. Basic concepts of microprocessors differences between. The microprocessor or cpu reads each instruction from the memory, decodes it. The register file is the component that contains all the general purpose. It is a computer processor that incorporates all the functions of cpu central processing unit on a single ic integrated circuit or at the most a few ics.
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