Execution unit this block executes the instruction. Introduction, microprocessor based computer system, architecture of. Microprocessor mcqs 1 what does the microprocessor comprise of. Unit1 introduction to 8086 ece department microprocessors and microcontrollers page 2 iv address bus. Abus is the internal 16bit alu data bus cbus is the internal 20bit address bus, 16bit data bus, and possibly control lines of the biu bus bbus has no true name but the function of the adder alu is to add the shifted 16bits starting address of 64 kbyte segment cs code segment to the 16bits ip instruction pointer offset into cs for next instruction to get the 20bit physical.
Bus interface unit biu microprocessor system design 320 general. Microprocessor and interfacing pdf notes mpi notes pdf. The 8086 also called iapx 86 is a 16bit microprocessor chip designed by intel between early 1976 and june 8, 1978, when it was released. The 8086 cpu is divided into two independent functional parts, the bus interface unit or biu, and the execution unit or eu.
Krishnananda, assistant professor, reva institute of technology, bangalore 3 39. The bus interface unit makes the system bus signals available for external interfacing of the devices. Biu sends out addresses, fetches instruction from memory, reads data from ports and memory and writes data to ports and memory. The control signals for maximum mode of operation are generated by the bus controller chip 8788. Bus interface unitbiu execution uniteu 8086 architecture. Due to this, overlapping instruction fetch with instruction execution increases the processing speed. Draw the format of a flag register of an 8086 microprocessor. In 1978, intel introduced the 16 bit microprocessor 8086 and 8088 in 1979. Microprocessor 8086 functional units tutorialspoint. The memory, address bus, data buses are shared resources between the two processors. The 80868088 partitions its memory into 65,536 physical memory segments. Write short notes on the execution unit eu and the bus interface unit biu. Block diagram of intel 8086 features of 8086 microprocessor. The control bus is bidirectional and assists the cpu in synchronizing control signals to.
Microprocessor consists of an alu, register array, and. Karande page 2 of 12 architecture or block diagram of 8086 microprocessor 8086 has two blocks biu bus interface unit and eu execution unit functions of bus interface unit the biu performs all bus operations such as instruction fetching, reading and writing. The internal functions of the 8086 processor are partitioned logically into two processing units. Additional copies of this manual or other intel literature may be obtained from. Presentation on 8086 microprocessor architecture group name. The internal architecture of intel 8086 is divided into 2 units. Fig 8086 internal block diagram the bus interface unit. The 8086 cpu is divided into two functional parts, the bus interface unit biu, and the execution unit eu.
It can support up to 64k io ports it provides 14 registers of 16bit size. It also contains 1 pointer register ip, which holds the address of the next instruction to executed by the eu. Memory segment block of 64k 65,536 consecutive memory bytes a segment number is a 16 bit. Pin diagram of 8086 microprocessor the microprocessor 8086 is a 16bit microprocessor available in different clock rates 5, 8, 10 mhz and packaged in a 40 pin dip or. Programs obtain access to code and data in the segments by changing the segment register content to point to the desired segments. On these lines the cpu sends out the address of the memory location that is to be written to or read from. This unit handles all transfer of data and addresses on the buses for the euexecution unit. The 8086 cpu is divided into two independent functional units. Intel 8086 family users manual october 1979 edx edge. Once inside the biu, the instruction is passed to the queue. The address bus consists of 16, 20, 24, or more parallel signal lines. The two independent functional parts of the 8086 cpu are. Bus interface unit biu execution unit eu the bus interface unit the biu handles all data and addresses on the buses for the execution unit such as it sends out addresses, fetches instructions from memory, reads data from. Bus interface unit and execution unit, are the two different functional units in 8086.
Microprocessors and interfacing a1423 unit i introduction. History of 8086 microprocessor the 8086 is a 16bit microprocessor chip designed by intel between early 1976 and mid1978. Introduction to 16 bit microprocessor only for knowledge. Bus interface unit part12 architecture of 8086 microprocessor with diagram. Internal architecture of 80888086 the 80888086 microprocessor has two units. Here you can download the free lecture notes of microprocessor and interfacing pdf notes mpi notes pdf materials with multiple file links to download. The bus interface unit contains bus interface logic, segment registers, memory addressing logic and a six byte instruction object code queue.
The 80868088 instruction queue is a buffer that holds opcode bytes that have been prefetched by the bus interface unit. The following pin function descriptions are for 8086 systems in either minimum or maximum mode the local bus in these descriptions is the direct multiplexed bus interface connection to the 8086 without regard to additional bus buffers symbol pin no type name and function ad15 ad0 216 39 io address data bus these lines constitute the. Bus interface unit bess interface unit a and b none of these a. To design an 8086 based system, it is necessary to know how to interface the 8086 microprocessor with memory and input and output devices.
Execution unit receives program instruction codes and data. The bus interface unit biu this unit handles all transfer of data and addresses on the buses for the euexecution unit. Has the ability to address up to 1 mbyte of memory via its 20bit address bus. Microprocessor 8086 functional units 8086 microprocessor is divided into two functional units, i. Pdf on aug 8, 2012, shree krishna khadka and others published a notebook on microprocessor system find, read and cite. A microprocessor is an integrated circuit with all the functions of a cpu however, it cannot be used stand alone since unlike a microcontroller it has no memory or peripherals 8086 does not have a ram or rom inside it. The bus interface unit biu performs all external bus. In 8086, a 6byte instruction queue is presented at the bus interface unit biu. Microprocessor and interfacing notes pdf mpi pdf notes book starts with the topics vector interrupt table, timing diagram, interrupt structure of 8086. Unitvi 1 draw block diagram of microprocessor 8086. Unit 1 introduction to 8086 ece department microprocessors and microcontrollers page 2 iv address bus. The 8086 cpu is divided into two independent functional parts, the bus interface unit biu and execution unit eu. Class notes introduction to intel 80868088 microprocessor. Unitvi 1 malp 3330705 1 draw block diagram of microprocessor 8086.
This unit sends out addresses, fetches instructions from memory, reads data from ports and memory and writes data to ports and memory. What is the maximum memory size that can be addressed by. The 8086 has two parts, the bus interface unit biu and the execution unit eu. Bus control alu eu control flag register instruction queue external bus. The intel 8088, released july 1, 1979, is a slightly modified chip with an external 8bit data bus allowing the use of cheaper and fewer supporting ics, and is notable as the processor used in the original ibm pc design. Overall, this unit makes you to understand how 8086 microprocessor is interfaced with memory and peripherals and how an 8086 based microcomputer system works.
It keeps the prefetch queue filled with instructions. Unit ii 8086 system bus structure 8086 signals basic configurations system bus timing system design using 8086 io programming. In this mode, all the control signals are given out by the. Or describe architecture of any one 16 bit microprocessor. Library files are collection of procedures that can be used in other programs. Mit unit 1 uniti id question option a option b option c option d correct option marks 1 which is 16 bit microprocessor. The concept of memory segmentation is used to solve this problem of using 20bit addresses in a 16bit microprocessor. Sharma, ce department 2150707 microprocessor and interfacing. Pdf a notebook on microprocessor system researchgate. The 8086, announced in 1978, was the first 16bit microprocessor introduced by. It provides a full 16 bit bidirectional data bus and 20 bit address bus. Execution unit gives instructions to biu stating from where to fetch the data and then decode and execute those instructions.
Condition code register flag register a and b none of these c 2 87 biu stand for. However, it has internal registers for storing intermediate and final results and interfaces with memory located outside it through the system bus. A microprocessor is an integrated circuit with all the functions of a cpu. The 8086 microprocessor has 20bit address bus, so it can address any one of 220 or 1,048,576 memory locations. Lm81 serial interface acpicompatible microprocessor system hardware monitor. Maximum mode 8086 system here, either a numeric coprocessor of the type 8087 or another processor is interfaced with 8086. Microprocessors 6 microprocessor is a controlling unit of a microcomputer, fabricated on a small chip capable of performing alu arithmetic logical unit operations and communicating with the other devices connected to it. The internal architecture 8086 microprocessor is as shown in the fig 1.
Ec6504 microprocessor and microcontrollers mmmmmimicrocontroller sce dept. Biu, instruction byte queue, 8086 instructions vary from 1 to 6 bytes. So, 20it can address any one of 2 10485761 mega byte memory locations. Difference between microprocessor and microcontroller in this video, we will understand the difference between microprocessor and microcontroller. The control signals for maximum mode of operation are. As shown in the below figure, the 8086 cpu is divided into two independent functional parts o bus interface unitbiu. This parallelism makes the fetch and execution of instructions independent. Here 16bit words will be stored in two consecutive memory locations. It is used to pre fetch and store at the maximum of 6 bytes of instruction code from the memory. Hence the microprocessor uses 20bit memory addresses.