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Exam Questions Papers - Engineering

Q1:

In 8085 microprocessor system, what will be the total delay provided by the following loop.
MVI A, 11H
LXI B, 12FFH
Delay: DCX B
XTHL
NOP
XRA B
JNZ Delay
where system clock is operating at 3 MHz.

A 3.154 msec

B 3.514 msec

C 2.644 msec

D 3.166 msec

ANS:A - 3.154 msec

8085 T-States MVI A, 11H 7 LX1 B, 12FFH 10 Delay: DCX B 6 XTHL 16 NOP 4 XRA B 4 JNZ Delay 10/7 Total T states = 7 + 10 + 255(6 + 16 + 4 + 4 + 7) + 10 = 9462 Therefore total delay introduced = = 3.154 m sec.