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The INTCON Register

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
GIE EEIE T0IE INTE RBIE T0IF INTF RBIF

 

The INTCON register is a readable and writable register which contains the various enable bits for all interrupt sources.

The meaning of INTCON might be (though this is only me thinking) INTurrpt CONtrol register. I have serached the net for the source of this acronym with no avail; if you find it please e-mail me.

Anyway, interrupt flag bits get set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global enable bit, GIE (INTCON<7>).

 

This register is used to configure the interrupt control logic circuitry. Bits 0 to 6 are used to configure the interrupt enable/disable statuses and the interrupt flags for the four interrupt sources. No interrupt to the CPU will result unless the GIE bit is set. The GIE bit is the bit INTCON<7> and when set, enables all un-masked interrupts.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x
GIE EEIE T0IE INTE RBIE T0IF INTF RBIF
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

R = Readable bit

W= Writable bit

U = Unimplemented bit, read as ‘0’

-n= Value at POR reset

 

bit 7:

GIE: Global Interrupt Enable bit
1 = Enables all un-masked interrupts
0 = Disables all interrupts

bit 6

EEIE: EE Write Complete Interrupt Enable bit
1 = Enables the EE write complete interrupt
0 = Disables the EE write complete interrupt

 

bit 5

T0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 interrupt
0 = Disables the TMR0 interrupt

 

bit 4:

INTE: RB0/INT Interrupt Enable bit
1 = Enables the RB0/INT interrupt
0 = Disables the RB0/INT interrupt
 

bit 3:

RBIE: RB Port Change Interrupt Enable bit
1 = Enables the RB port change interrupt
0 = Disables the RB port change interrupt

 

bit 2:

T0IF: TMR0 overflow interrupt flag bit
1 = TMR0 has overflowed (must be cleared in software)
0 = TMR0 did not overflow

 

bit 1:

INTF: RB0/INT Interrupt Flag bit
1 = The RB0/INT interrupt occurred
0 = The RB0/INT interrupt did not occur

 

BIT 0:

RBIF: RB Port Change Interrupt Flag bit
1 = When at least one of the RB7:RB4 pins changed state (must be cleared in software)
0 = None of the RB7:RB4 pins have changed state