Correct Answer - Option 4 : 5
Explanation:
An interrupt is an event that occurs randomly in the continuation of something depending upon call priority, you decide whether to neglect or attend it.
8051 architecture handles 5 interrupt sources, out of which two are internal (Timer interrupts), two are external and one is a serial interrupt. Each of their interrupts has its vector address.
The highest interrupt priority upon reset in 8051 is external interrupt 0.
|
Priority
|
Interrupt source
|
Interrupt Bit / flag
|
|
1
|
External Interrupt 0
|
INT 0
|
|
2
|
Timer Interrupt 0
|
TF 0
|
|
3
|
External Interrupt 1
|
INT 1
|
|
4
|
Timer Interrupt 1
|
TF 1
|
|
5
|
Serial Interrupt
|
TI / RI
|
Hence option (4) is the correct answer.
As per 8051 interrupt priority, the lowest priority interrupts are not served until the microcontroller is finished with higher priority interrupts.
