Pin functions of 8086-microprocessor, Assembly Language

Assignment Help:

Pin functions for the minimum mode operation of 8086 are following:

1) M/I/O -Memory/IO: This is a status line logically equivalent to S2 in maximum mode. When it is low, it denotesthe CPU is having an I/O operation, and when it is high, it denotes that the CPU is having a memory operation. In the previous T4this line becomes active and remains active till last T4 of the current cycle. During local bus this is tristated "hold acknowledge".

2) INTA-interrupt Acknowledge: This signal is utilized as a read strobe for interrupt acknowledge cycles.  In other terms, when it goes low, this means that the processor has accepted the interrupt. It is active low during T3, T2 and Tw of each interrupt acknowledge cycle.

3) ALE-Address  Latch  Enable: This  output  signal  indicates  the  availability  of  the  valid  address  on  the address/data lines, and is associated to latch enable input of latches. This signal is active high and is never tristated.

4) DT/R  -Data  Transmit/Receive: This output is utilized to decide the direction of data flow through the transreceivers (bidirectional  buffers). When the processor sends data, this signal is high and when the processor is receiving data, this signal is low. Logically, this is corresponding toS1 inmaximum mode. Its timing is the similar as M/I/O. This is tri stated during 'hold acknowledge'.

5) DEN-Data Enable: This signal denote the availability of valid data over the address/data lines. It is utilized to enable the Trans receivers (bidirectional buffers) to separate the data from the multiplexed address/data signal. It is active from the centre of T2 until the middle of T4.

DEN is tristated during 'hold acknowledge' cycle. HLDA-Hold/Holdand HOLD Acknowledge: When the HOLD line go high, it denote to the processor that another master is requesting the bus access. , in the middle of the next clock cycle after receiving the HOLD request the processor is use the hold acknowledge signal on HLDA pin after completing the current bus (instruction)  cycle. At the same time, the processor floats the control lines andlocal bus. When the processor detects the HOLD line low then it lowers the HLDA signal. HOLD is asynchronous input and it should be synchronized externally.

 


Related Discussions:- Pin functions of 8086-microprocessor

Ror-logical instruction-microprocessor, ROR : Rotate Right without Carry: ...

ROR : Rotate Right without Carry: This instruction rotates the contents of destination operand to the bit-wise right either by one or by the count specified in register CL, exclud

FIRE ALARM PROGRAMMING, PLEASE MAY YOU ASSIST ME WITH SAMPLE CODES FOR PROG...

PLEASE MAY YOU ASSIST ME WITH SAMPLE CODES FOR PROGRAMING A FIRE ALARM MINI PROJECT

Sequence of interrupts, As an instance of the normal priority mode, imagine...

As an instance of the normal priority mode, imagine that initially AEOI is equal to 0 and all the ISR and IMR bits are clear. Also consider that, as shown in given figure, requests

Explore debugger, add the contents of the defined memory locations 120, 133...

add the contents of the defined memory locations 120, 133, 122 using mov instruction in dosbox

Memory segmentation-microprocessor, Memory Segmentation : The  memory ...

Memory Segmentation : The  memory in an 8086/8088  based system is organized as segmented memory. In this scheme, the whole physically available memory can be divided into a n

Pointer(ptr)-assemblers directive-microprocessor, PTR : Pointer:- The p...

PTR : Pointer:- The pointer operator which is used to declare the type of a variable, label or memory operand. The operator PTR is prefixed by either WORD or BYTE. If the prefi

CONSTANTS, Ask question #MinimuWHAT ARE CONSTANTS AND WHAT DO THEY DO?m 100...

Ask question #MinimuWHAT ARE CONSTANTS AND WHAT DO THEY DO?m 100 words accepted#

Aas-arithmetic instruction-microprocessor, AAS: ASCII Adjust AL After Subt...

AAS: ASCII Adjust AL After Subtraction AAS instruction correct the result in the AL register after subtracting operation of two unpacked ASCII operands. The result is in unpacked

Data copy/transfer instructions-microprocessor, Data copy/transfer Instruct...

Data copy/transfer Instructions MOV: This data transfer instruction transfers data from one register or memory location to another register or memory location. The source can

Assume-assemblers directive-microprocessor, ASSUME: Assume Logical Segment...

ASSUME: Assume Logical Segment Name:- The ASSUME directive which is used to inform the assembler, the specified names of the logical segments to be consider for different segme

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd