•- Five
interrupt sources in order of polling
(priority) sequence are:
• External Interrupt 0
•
Timer 0
•
External Interrupt 1
•
Timer 1
•
Serial Port
-The polling sequence
is fixed but each interrupt type can be programmed to one of two priority levels.
-If two interrupts of same priority occur simultaneously
then polling sequence will determine which is
serviced first.
•- External
interrupts can be programmed for edge
or level sensitivity.
-- Each interrupt type has a separate vector address.
-- All interrupts
are disabled after a system reset and enabled individually by software.