PIC17C75X
6.3
Peripheral Interrupt Request
Register1 (PIR1) and Register2 (PIR2)
Note: These bits will be set by the specified con-
dition, even if the corresponding interrupt
enable bit is cleared (interrupt disabled), or
the GLINTD bit is set (all interrupts dis-
abled). Before enabling an interrupt, the
user may wish to clear the interrupt flag to
ensure that the program does not immedi-
ately branch to the peripheral interrupt ser-
vice routine.
These registers contains the individual flag bits for the
peripheral interrupts.
FIGURE 6-5: PIR1 REGISTER (ADDRESS: 16h, BANK 1)
R/W - 0 R/W - 0 R/W - 0 R/W - 0 R/W - 0 R/W - 0 R - 1 R - 0
R = Readable bit
W = Writable bit
-n = Value at POR reset
RBIF TMR3IF TMR2IF TMR1IF CA2IF
CA1IF TX1IF RC1IF
bit7
bit0
bit 7:
bit 6:
RBIF: PORTB Interrupt on Change Flag bit
1 = One of the PORTB inputs changed (software must end the mismatch condition)
0 = None of the PORTB inputs have changed
TMR3IF: TMR3 Interrupt Flag bit
If Capture1 is enabled (CA1/PR3 = 1)
1 = TMR3 overflowed
0 = TMR3 did not overflow
If Capture1 is disabled (CA1/PR3 = 0)
1 = TMR3 value has rolled over to 0000h from equalling the period register (PR3H:PR3L) value
0 = TMR3 value has not rolled over to 0000h from equalling the period register (PR3H:PR3L) value
bit 5:
bit 4:
TMR2IF: TMR2 Interrupt Flag bit
1 = TMR2 value has rolled over to 0000h from equalling the period register (PR2) value
0 = TMR2 value has not rolled over to 0000h from equalling the period register (PR2) value
TMR1IF: TMR1 Interrupt Flag bit
If TMR1 is in 8-bit mode (T16 = 0)
1 = TMR1 value has rolled over to 0000h from equalling the period register (PR1) value
0 = TMR1 value has not rolled over to 0000h from equalling the period register (PR1) value
If Timer1 is in 16-bit mode (T16 = 1)
1 = TMR2:TMR1 value has rolled over to 0000h from equalling the period register (PR2:PR1) value
0 = TMR2:TMR1 value has not rolled over to 0000h from equalling the period register (PR2:PR1) value
bit 3:
bit 2:
bit 1:
bit 0:
CA2IF: Capture2 Interrupt Flag bit
1 = Capture event occurred on RB1/CAP2 pin
0 = Capture event did not occur on RB1/CAP2 pin
CA1IF: Capture1 Interrupt Flag bit
1 = Capture event occurred on RB0/CAP1 pin
0 = Capture event did not occur on RB0/CAP1 pin
TX1IF: USART1 Transmit Interrupt Flag bit (State controlled by hardware)
1 = USART1 Transmit buffer is empty
0 = USART1 Transmit buffer is full
RC1IF: USART1 Receive Interrupt Flag bit (State controlled by hardware)
1 = USART1 Receive buffer is full
0 = USART1 Receive buffer is empty
1997 Microchip Technology Inc.
Preliminary
DS30264A-page 33
MICROCHIP [ MICROCHIP ]
