0
Intel 8085
Introduced by Intel in 1977, the Intel 8085 is an 8-bit microprocessor that is binary-compatible with Intel 8080. It only requires a +5-volt power supply and has been used as a microcontroller.
1,493 Questions
In DMA as the name suggest the memory can be accessed directly by i/o module. Thus overcome the drawback of programmed i/o and interrupt driven i/o where the CPU is responsible for extracting data from the memory for output & storing data in memory for input. DMA provids different information.
i) which operation (read/write) to be performed.
ii) The address of i/o device which is to be used.
It depends on whether the machine code is one, two, or three bytes long, and on whether or not the instruction transferred control to another location.
In the case of a non-jump single byte instruction, the PC will have a value of 2060H after the instruction is complete, and it will be 2061H or 2062H after a two or three byte instruction. In the case of a jump, call, or interrupt, the PC will depend on the instruction.
Write an assembly program to multiply a numberr by 4?
To multiply a number by 4, do a left shift twice. If the number is in the accumulator, do...
RAL
RAL
XRI 0FCH
How stack pointer registers are involved in the execution of push and pop instruction?
If the stack is empty assume the stack pointer has a value of P. when you push something on the stack you increment P. when you pull something from stack you decrement P.
Calculate t states of an instruction?
For calculating the T states of the any instruction ,you should know how many machine cycles does the instruction contains and the number of T states in each of the machine cycles
for example,
In a 8085 microprocessor set ,the instr. JMP contains three machine cycles
- opcode fetch which is of 4T or 6T states
- memory read which is of 3T states
- another memory read which is again of 3T states
Therefore , the instr. JMP has a total of 10T states
Mention any one byte call instruction and the address to which it is points to?
RST 2 is one example of a one byte call instruction. It points to 0010H.
In computing, an autovector is an interrupt vector representing a priority level, from which the processor determines the target address.
Write a program find maximum number from given three number in 8085 micro processor?
This code find s the largest and the smallest number in an array terminated with a zero. It's not exactely a perfect match for the question but I dion't believe in answering question papers. It's always good to let the student do some work. There's enough example here to cut it down to provide an answer to the question.
CODE SEGMENT
MOV AX,DATA
MOV DS,AX ; initialize DS
MOV DI, OFFSET ARRAY ; DI points to the array
MOV AX, [DI] ; AX contains the first element
MOV LARGEST, AX ; initialize largest
MOV SMALLEST, AX ; initialize smallest
MOV CX,6 ; loop counter
Al: MOV AX, [DI] ; get array value
CMP AX, SMALLEST ; [DI] = smallest?
JGE A2 ; yes : skip
MOV SMALLEST, AX ; no : move [DI] to smallest
JMP A3 ; as it is smallest, thus no need
; to compare it with the largest . i
A2: CMP AX,LARGEST ; [DI] = largest
JLE A3 ; yes : skip
MOV LARGEST, AX ; no : mov [Dl] to largest
A3: ADD DI,2 ; point to next number
LOOP A1 ; repeat the loop until CX = 0
MOV AX, 4C00h
INT 21h ; halt, return to DOS
CODE ENDS
DATA SEGMENT
ARRAY DW -1, 2000, -4000, 32767, 500, 0
LARGEST DW ?
SMALLEST DW ?
DATA ENDS
END.
What are Temporary registers w and z in 8085?
it is used as a temporary variable when the command XCHG is used, here two register values are xchanged with the help of this wz 16 bit register, this is not programmable.
What is a supervisor call interrupt?
SVC (supervisor-call): A request from the user-program to the kernel (or supervisor), to do something like open a file, allocate memory, create a new process etc.
In x86 platform SVCs are executed via "INT nn" machine instruction, that's what Intel calls 'software interrupt'.
Describe the function purpose and participants in the grand jury?
A jury of 12 to 23 persons convened in private session to evaluate accusations against persons charged with crime and to determine whether the evidence warrants a bill of indictment.
Source: Answers.com
Which instruction consume the maximum T state in its execution?
for 8085 microprocessor CALL [32-bit address] which is (unconditional ) consumes maximum(18) T states.
Why i can't enable and disable interrupts of my AVR for several times?
It's impossible :o) You can disable and enable any interrupt source by setting or clearing corresponding bit in proper control register. Show me your code - we will see what can be done wrong.
Asar
fotousa@interia.pl
You can set bit I on SREG by 1 to enable global interrupt or by 0 to disable it.
in c programming you can write
#asm ("sei") //to enable global interupt
#asm ("cli") //to disable global interupt
M. Wicaksono A.
Why data and address buses are tristated in 8085?
In the general case, a bus is tristated to allow more than one source to drive it. This can be the simple case of a bi-directional bus, or the more complex case of a multi-master bus configuration.
In the 8085, the address bus is tristated when a HOLD/HLDA sequence is in process, allowing another bus master to control the bus. The data bus is tristated for the same reason, and also to allow bi-directional data flow (read vs write) to occur.
