
PIC17C4X
DS30412B-page 22
1996 Microchip Technology Inc.
5.1
Interrupt Status Register (INTSTA)
The Interrupt Status/Control register (INTSTA) records
the individual interrupt requests in flag bits, and con-
tains the individual interrupt enable bits (not for the
peripherals).
The PEIF bit is a read only, bit wise OR of all the periph-
eral flag bits in the PIR register (Figure 5-4).
Note:
T0IF, INTF, T0CKIF, or PEIF will be set by
the specified condition, even if the corre-
sponding interrupt enable bit is cleared
(interrupt disabled) or the GLINTD bit is set
(all interrupts disabled).
FIGURE 5-2: INTSTA REGISTER (ADDRESS: 07h, UNBANKED)
R - 0
PEIF
bit7
R/W - 0 R/W - 0 R/W - 0
T0CKIF
T0IF
R/W - 0
PEIE
R/W - 0
T0CKIE
R/W - 0
T0IE
R/W - 0
INTE
INTF
R = Readable bit
W = Writable bit
- n = Value at POR reset
bit0
bit 7:
PEIF
This bit is the OR of all peripheral interrupt flag bits AND’ed with their corresponding enable bits.
1 =A peripheral interrupt is pending
0 =No peripheral interrupt is pending
T0CKIF
: External Interrupt on T0CKI Pin Flag bit
This bit is cleared by hardware, when the interrupt logic forces program execution to vector (18h).
1 =The software specified edge occurred on the RA1/T0CKI pin
0 =The software specified edge did not occur on the RA1/T0CKI pin
T0IF
: TMR0 Overflow Interrupt Flag bit
This bit is cleared by hardware, when the interrupt logic forces program execution to vector (10h).
1 =TMR0 overflowed
0 =TMR0 did not overflow
INTF
: External Interrupt on INT Pin Flag bit
This bit is cleared by hardware, when the interrupt logic forces program execution to vector (08h).
1 =The software specified edge occurred on the RA0/INT pin
0 =The software specified edge did not occur on the RA0/INT pin
PEIE
: Peripheral Interrupt Enable bit
This bit enables all peripheral interrupts that have their corresponding enable bits set.
1 =Enable peripheral interrupts
0 =Disable peripheral interrupts
T0CKIE
: External Interrupt on T0CKI Pin Enable bit
1 =Enable software specified edge interrupt on the RA1/T0CKI pin
0 =Disable interrupt on the RA1/T0CKI pin
T0IE
: TMR0 Overflow Interrupt Enable bit
1 =Enable TMR0 overflow interrupt
0 =Disable TMR0 overflow interrupt
INTE
: External Interrupt on RA0/INT Pin Enable bit
1 =Enable software specified edge interrupt on the RA0/INT pin
0 =Disable software specified edge interrupt on the RA0/INT pin
: Peripheral Interrupt Flag bit
bit 6:
bit 5:
bit 4:
bit 3:
bit 2:
bit 1:
bit 0: