General bus operation-microprocessor, Assembly Language

General Bus Operation

The 8086 has a joined data and address bus commonly referred to as a time multiplexed address and data bus. The major reason behind  multiplexing address and data  over the similar pins is the  maximum utilization of processor pins and it facilitates the use of 40 pin standard  DIP package. The bus may be de-multiplexed by using a few transceivers and latches, whenever required. In the following text, a general bus operation cycle is described.

Mainly all the processor bus cycles contain of at least 4 clock cycles. These are referred to as T4, T3, T2 and T1• the address is transmitted by the processor during T1. It is present on the bus just for 1 cycle. During T2, for example- in the next cycle, the bus is tristated for altering the direction of bus for the following data read cycle. The data transfer takes place during T4and T3. In case, an addressed device is slow and shows

'NOT READY' status the wait states Tware inserted between T3 and T4. During wait periodthese  all clock states are known wait states (Tw),idle states (Ti),  or inactive  states. The processor utilize these cycles for internal housekeeping.  The  address  latch  enable  (ALE)  signal  is  emitted  during  T,  by  the bus controller (maximum mode) orthe  processor (minimum mode) depending upon the status of the MN/MX input. The negative edge of this ALE pulse is utilized to separate the address and the status or data information. In maximum mode, the status lines S0, S1 and S2 are utilize to indicate the type of operation as described in the pin description of this unit. Status bits BHE/s7 are multiplexed with BHE and signalhigher order address bits. Address is valid during T1 while the status bits S3  to S7  are valid during T2  through T4. The Figure2.7 shows a general bus operation cycle of 8086.

 

1520_general bus.jpg

Posted Date: 10/10/2012 2:49:42 AM | Location : United States







Related Discussions:- General bus operation-microprocessor, Assignment Help, Ask Question on General bus operation-microprocessor, Get Answer, Expert's Help, General bus operation-microprocessor Discussions

Write discussion on General bus operation-microprocessor
Your posts are moderated
Related Questions
write a program using assembly language that print your name

init_lcd                        ;(this initialises a 2 row lcd)     bcf     TRISA,0             ;PORTA bit 0 as an output (lcd RS pin)     bcf     TRISA,1             ;PORTA bit 1


check the al-register for palindromic number

do you have experts that know 4 digit 7_Seg dispaly

LDS/LES Instruction execution :  LAHF : Load AH from Lower Byte of Flag: - This instruction loads the AH register with the lower byte of the flag register. This instruction ca

Write an application that does the following:(1) fill an array with 50 random integers; (2) loop through the array, displaying each value, and count the number of negative values;

SHL/SAL : Shift logical/Arithmetic Left: These instructions shift the operand byte or word bit by bit to the left and insert 0 in the newly introduced least significant bits. In c

Write an assembly language program that will display (print) a list of the Decades 2010, 2020, 2030... 2100 to the screen using a while loop.

code to add two matrices