The Bus Interface Unit (BIU): It provides the interface of 8086 to external memory and I/O devices via the System Bus . It performs various machine cycles such as memory read, I/O read etc. to transfer data between memory and I/O devices.
What are the functions of BIU and EU in 8086 microprocessor?
The 8086 CPU is organized as two separate processors, called the Bus Interface Unit (BIU) and the Execution Unit (EU). The BIU provides H/W functions, including generation of the memory and I/O addresses for the transfer of data between the outside world -outside the CPU, that is- and the EU.
What is the function of Biu in 8086 microprocessor Mcq?
BIU has the following functions: Instruction fetching, Instruction queuing, Operand fetching and storage, Address relocation and Bus control .
What is the function of 8086 microprocessor?
8086 Microprocessor is an enhanced version of 8085Microprocessor that was designed by Intel in 1976. It is a 16-bit Microprocessor having 20 address lines and16 data lines that provides up to 1MB storage. It consists of powerful instruction set, which provides operations like multiplication and division easily .
What is the function of BHE pin in 8086 microprocessor?
BHE stands for Bus High Enable. It is available at pin 34 and used to indicate the transfer of data using data bus D8-D15 . This signal is low during the first clock cycle, thereafter it is active.
What is the meaning of BIU?
When stylized as BIU, stands for bold, italic and underline , three common ways to mark emphasis in typography.
Why is 8086 divided into BIU and EU?
Explanation: The architecture of 8086 is divided into two functional parts i.e., i. ... Functional division of architecture speeds up the processing, since BIU and EU operate parallely and independently i.e. , EU executes the instructions and BIU fetches another instruction from the memory simultaneously.
What is addressing mode in microprocessor?
Prerequisite – Addressing modes, Addressing modes in 8085 microprocessor. The way of specifying data to be operated by an instruction is known as addressing modes. This specifies that the given data is an immediate data or an address. It also specifies whether the given operand is register or register pair.
Which Interrupt has the highest priority Mcq?
Explanation: TRAP is the internal interrupt that has highest priority among all the interrupts except the Divide By Zero (Type 0) exception.
Which of the given signal has highest priority?
| Interrupt Priority Mask | TRAP (RST 4.5) 1 (Highest) Non-maskable | RST 7.5 2 Maskable | RST 6.5 3 Maskable | RST 5.5 4 Maskable |
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What is STD in microprocessor?
This instruction is used to set the Direction Flag to 1 so that SI/DI will automatically decrement when one of the string instructions executes.
How many pins are there in 8086 microprocessor?
| A17/S4 A16/S3 Function | 1 0 Code segment access | 1 1 Data segment access |
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Why is 8086 a 16 bit microprocessor?
Originally Answered: Why is the Intel 8086 CPU called a 16-bit CPU? The registers and memory word size of the 8086 are 16 bit – meaning it can operate on 16 bit values and address 65536 bytes of memory at a time.
What is the function of the signals M IO and BHE in the 8086?
The BHE and A0 signals address low, high or both bytes. From T1 to T4, the M/IO signal indicates a memory or I/O operation . At T2, the address is removed from the local bus and is sent to the output. The bus is then tristated.
What is function of AD0 AD7 pins?
AD0-AD7 constitutes the Address/Data bus . They are time multiplexed. These pins are used for least significant bits of address bus in the first machine clock cycle and used as data bus for second and third clock cycle.
How is clock signal generated in 8086?
8086 requires an external clock generator/driver chip Intel 8254 to generate the 8086 clock input signal. The 8086 divides the external clock connected at the CLK pin internally by three. Therefore for 5 MHz internal clock,the 8284 must generate 15 MHz at its output,which will be given to the CLK pin of 8086.
What does BIU stand for in COA?
BIU – Bus interface unit . Some of the functions of BIU are: It sends out tasks. It fetches instructions from memory. It reads data from memory and ports.
What is the effective address of the instruction MOV AX BX?
8 Relative Based Indexed:
Eg: MOV AX,50H[BX][SI] –Effective address is 10H* DS+[BX]+[SI]+50H •For the control transfer instructions, the addressing modes depend upon whether the destination location is within the same segment or in a different one.
What is the full form of BPS in computer?
Bits per second (bps), a data rate unit. Bytes per second (Bps), a data rate unit.
What does BIU stand for police?
The Borough Intelligence Unit (BIU) office is situated on the first floor opposite DCI Meadows’ office, it is adjacent to the unused Computer Rooms.
What are the different operating modes of 8086?
The 8086 microprocessor can work in two modes of operations : Minimum mode and Maximum mode . In the minimum mode of operation the microprocessor do not associate with any co-processors and can not be used for multiprocessor systems. In the maximum mode the 8086 can work in multi-processor or co-processor configuration.
What is the purpose of addressing modes?
An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere.
Where is physical address in 8086 microprocessor?
I learnt that the physical address is calculated by shifting the segment address (16-bit) left 4 times and adding it with the 16-bit offset address . The memory in the 8086 architecture is 1M.
When push instruction is executed?
| Que. In PUSH instruction, after each execution of the instruction, the stack pointer is | b. decremented by 1 | c. incremented by 2 | d. decremented by 2 | Answer:decremented by 2 |
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Which is the highest priority interrupt in 8086?
(A) NMI (Non Maskable Interrupt) – It is a single pin non maskable hardware interrupt which cannot be disabled. It is the highest priority interrupt in 8086 microprocessor.
Which interrupt is non maskable?
Non-Maskable Interrupts are those which cannot be disabled or ignored by microprocessor. TRAP is a non-maskable interrupt. It consists of both level as well as edge triggering and is used in critical power failure conditions.
Why trap is both edge and level triggered?
The positive edge of the TRAP signal sets the D flip-flop. Because of the AND gate, however the final TRAP also depends on a sustained high level TRAP input . This is why the TRAP is both edge and level sensitive. This also avoids false triggering caused by noise and transients.
Which interrupt has lowest priority?
Explanation: The interrupt, RI=TI (serial port) is given the lowest priority among all the interrupts.
Why 8086 is named so?
Chip numbers were just 4 digits. They already had an 8085, and in the naming scheme of that time, defined as exactly four digits for consistency, the last digit was meant for distinguishing chip variants. So it was a fairly natural choice to pick the next number after the 8085, 8086, with the 6 meaning “ 16 bit ”.
Which interrupt is an maskable Mcq?
An interrupt whose interrupt service can be stopped from being serviced temporarily is called Maskable Interrupt.
Why trap is highest priority interrupt?
| Que. Which interrupt has the highest priority? | b. TRAP | c. RST6.5 | d. RST6.6 | Answer:RST6.5 |
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Is 8086 a RISC or CISC?
The 8086-based processors are an example of a complex instruction set computer, or CISC, architecture . Many newer processor designs use a reduced instruction set computer, or RISC, architecture instead.
How many flags does 8086 have?
(a) Status Flags – There are 6 flag registers in 8086 microprocessor which become set(1) or reset(0) depending upon condition after either 8-bit or 16-bit operation. These flags are conditional/status flags.
What is the use of trap flag in 8086?
Trap Flag (T) in 8086 is used for on-chip debugging . Setting the trap flag puts the microprocessor into a single step mode for debugging. In single stepping, the microprocessor executes an instruction and enters into a single step ISR.
What is the function of DF flag?
The direction flag is a flag that controls the left-to-right or right-to-left direction of string processing , stored in the FLAGS register on all x86-compatible CPUs. It is bit number 10.
What is the function of index register in microprocessor?
Index register used to determine the address of an operand . An index register in a computer’s CPU is a processor register used for modifying operand addresses during the run of a program, typically for doing vector/array operations.
Which are the pin 16 to pin number pin 2 in 8086?
AD 0 – AD 15 – Pin number 2 to 16 and 39 – These are the multiplexed address and data bus. We know that the 8086 microprocessor has 20-bit address bus and 16-bit data bus. So, the 16 lines of the address and data bus are multiplexed together so as to reduce the number of lines inside the IC.
What is the maximum clock frequency in 8086?
5 Mhz is the Maximum clock frequency in 8086.
What are the flags in 8086 microprocessor?
| Flag Bit Function | P This is even parity flag. When result has even number of 1, it will be set to 1, otherwise 0 for odd number of 1s | CY This is carry bit. If some operations are generating carry after the operation this flag is set to 1 |
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What is the role of the following signals Ale rd WR M io?
ALE – It is an Address Latch Enable signal. ... IO/M’ – It is a status signal which determines whether the address is for input-output or memory . When it is high(1) the address on the address bus is for input-output devices.
What is the role of these signals Ale rd WR M io?
Three control signals are RD, WR & ALE. RD − This signal indicates that the selected IO or memory device is to be read and is ready for accepting data available on the data bus . WR − This signal indicates that the data on the data bus is to be written into a selected memory or IO location.
What is the role of status line S4 and S3 in the 8086?
Status bits S3 and S4 indicate the segment register that is being used to generate the address the address and bit S5 reflects the contents of the IF flag. S6 is always held at 0 and indicates that an 8086 is controlling the system bus.
