Specifications

Chapter 2 - Microcontroller PIC16F84

bit 0 RBIF (RB Port Change Interrupt Flag bit) Bit which informs about changes on pins 4, 5, 6 and 7

of port B.

1=at least one pin has changed its status

0=no change occured on any of the pins

bit 1 INTF (INT External Interrupt Flag bit) External interrupt occured.

1=interrupt occured

0=interrupt did not occur

If a rising or falling edge was detected on pin RB0/INT, (which is defined with bit INTEDG in OPTION

interrupt.

bit 2 T0IF (TMR0 Overflow Interrupt Flag bit) Overflow of counter TMR0.

1= counter changed its status from FFh to 00h

0=overflow did not occur

Bit must be cleared in program in order for an interrupt to be detected.

bit 3 RBIE (RB port change Interrupt Enable bit) Enables interrupts to occur at the change of status

of pins 4, 5, 6, and 7 of port B.

1= enables interrupts at the change of status

0=interrupts disabled at the change of status

If RBIE and RBIF were simultaneously set, an interrupt would occur.

bit 4 INTE (INT External Interrupt Enable bit) Bit which enables external interrupt from pin RB0/INT.

1=external interrupt enabled

0=external interrupt disabled

If INTE and INTF were set simultaneously, an interrupt would occur.

bit 5 T0IE (TMR0 Overflow Interrupt Enable bit) Bit which enables interrupts during counter TMR0

overflow.

1=interrupt enabled

0=interrupt disabled

If T0IE and T0IF were set simultaneously, interrupt would occur.

Bit 6 EEIE (EEPROM Write Complete Interrupt Enable bit) Bit which enables an interrupt at the end

of a writing routine to EEPROM

1=interrupt enabled

0=interrupt disabled

If EEIE and EEIF (which is in EECON1 register) were set simultaneously , an interrupt would occur.

Bit 7 GIE (Global Interrupt Enable bit) Bit which enables or disables all interrupts.

1=all interrupts are enabled

0=all interrupts are disabled

PIC16F84 has four interrupt sources:

1. Termination of writing data to EEPROM

2. TMR0 interrupt caused by timer overflow

3. Interrupt during alteration on RB4, RB5, RB6 and RB7 pins of port B.

4. External interrupt from RB0/INT pin of microcontroller

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