PIC18F2450/4450
DS39760A-page 90
Advance Information
2006 Microchip Technology Inc.
8.3
PIR Registers
The PIR registers contain the individual flag bits for the
peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Request (Flag) registers (PIR1 and PIR2).
Note 1: Interrupt flag bits are set when an interrupt
condition occurs regardless of the state of
its corresponding enable bit or the Global
Interrupt Enable bit, GIE (INTCON<7>).
2: User
software
should
ensure
the
appropriate interrupt flag bits are cleared
prior to enabling an interrupt and after
servicing that interrupt.
REGISTER 8-4:
PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
U-0
R/W-0
R-0
U-0
R/W-0
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
bit 7
Unimplemented: Read as ‘0’
bit 6
ADIF: A/D Converter Interrupt Flag bit
1
= An A/D conversion completed (must be cleared in software)
0
= The A/D conversion is not complete
bit 5
RCIF: EUSART Receive Interrupt Flag bit
1
= The EUSART receive buffer, RCREG, is full (cleared when RCREG is read)
0
= The EUSART receive buffer is empty
bit 4
TXIF: EUSART Transmit Interrupt Flag bit
1
= The EUSART transmit buffer, TXREG, is empty (cleared when TXREG is written)
0
= The EUSART transmit buffer is full
bit 3
Unimplemented: Read as ‘0’
bit 2
CCP1IF: CCP1 Interrupt Flag bit
Capture mode:
1
= A TMR1 register capture occurred (must be cleared in software)
0
= No TMR1 register capture occurred
Compare mode:
1
= A TMR1 register compare match occurred (must be cleared in software)
0
= No TMR1 register compare match occurred
PWM mode:
Unused in this mode.
bit 1
TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1
= TMR2 to PR2 match occurred (must be cleared in software)
0
= No TMR2 to PR2 match occurred
bit 0
TMR1IF: TMR1 Overflow Interrupt Flag bit
1
= TMR1 register overflowed (must be cleared in software)
0
= TMR1 register did not overflow