
PIC18F1230/1330
2009 Microchip Technology Inc.
DS39758D-page 127
FIGURE 14-6:
PWM TIME BASE INTERRUPT TIMING, SINGLE-SHOT MODE
FIGURE 14-7:
PWM TIME BASE INTERRUPTS, CONTINUOUS UP/DOWN COUNT MODE
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
1
FOSC/4
PTMR
FFEh
FFFh
000h
1
PTIF bit
2
Note 1:
Interrupt flag bit, PTIF, is sampled here (every Q1).
2:
PWM Time Base Period register, PTPER, is loaded with the value FFFh for this example.
Qc
1
PTMR
FFEh
FFFh
000h
1
2
A: PRESCALER = 1:1
B: PRESCALER = 1:4
PTMR_INT_REQ
Q4
PTIF bit
PTMR_INT_REQ
000h
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
FOSC/4
PTMR
002h
001h
000h
001h
002h
Note 1:
Interrupt flag bit, PTIF, is sampled here (every Q1).
Qc
1
PTMR
002h
001h
002h
1
PTDIR bit
1
PRESCALER = 1:1
PRESCALER = 1:4
PTIF bit
PTMR_INT_REQ
PTDIR bit
Q4
PTIF bit
PTMR_INT_REQ
1
000h