PIC12F683 has got one external interrupt pin (GP2, pin 5) which is edge-triggered:
- rising edge if INTEDG bit in OPTION register is SET,or
- falling edge if INTEDG bit in OPTION register is CLEAR
In this experiment we are going to simulate an external interrupt event by a tact switch which when pressed gives a falling edge (5->0V) to external interrupt pin. When a valid edge appears on GP2/INT pin, the INTF bit (INTCON<1>) is set. This interrupt can be disabled by clearing INTE control bit (INTCON<4>). While exiting from the Interrupt Service Routine, INTF flag must be cleared to re-enable the interrupt again. ANSEL and CMCON0 must be initialized to configure GPIO as digital I/Os.
On the arrival of an interrupt, the new value of counter will increase by 1 and is displayed as no. of interrupts serviced.
Experimental Setup:
External interrupt will be simulated by a tact switch on the board.
So connect SW1 to GP2 with a jumper wire. For display purpose we will again use a hyperterminal window on a PC.
