2. What is an Interrupt?
• It means interrupting the normal
execution of the microprocessor.
3. Steps whenever there is an interrupt?
current
PC PC contents are
stored in stack
100
101
102
103
104
103
103
STACK
SP
4. 4
Interrupts in 8085
Main routine
Interrupt
Save
program
counter
Disable
interrupts
Send out
interupt
acknowledge
Service routine
Go to
service
routine
Get
original
program
counter
Go back
EI
RET
11. The addresses to which program control goes:
NAME VECTOR
ADDRESSES
RST 7.5 003CH(7.5 X 0008H)
RST 6.5 0034H(6.5 X 0008H)
RST 5.5 002CH(5.5 X 0008H)
TRAP 0024H(4.5 X 0008H)
Absolute address is calculated by multiplying the RST value
with 0008H.