
PIC16C71X
DS30272A-page 32
1997 Microchip Technology Inc.
FIGURE 6-3:
TIMER0 TIMING: INTERNAL CLOCK/PRESCALE 1:2
FIGURE 6-4:
TIMER0 INTERRUPT TIMING
PC+6
PC-1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
PC
(Program
Counter)
Instruction
Fetch
TMR0
PC
PC+1
PC+2
PC+3
PC+4
PC+5
PC+6
T0
NT0+1
MOVWF TMR0
MOVF TMR0,W
Write TMR0
executed
Read TMR0
reads NT0
Read TMR0
reads NT0
Read TMR0
reads NT0
Read TMR0
reads NT0
Read TMR0
reads NT0 + 1
T0+1
NT0
Instruction
Execute
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
Q2
Q1
Q3
Q4
1
OSC1
CLKOUT(3)
Timer0
T0IF bit
(INTCON<2>)
FEh
GIE bit
(INTCON<7>)
INSTRUCTION
PC
Instruction
fetched
PC
PC +1
0004h
0005h
Instruction
executed
Inst (PC)
Inst (PC-1)
Inst (PC+1)
Inst (PC)
Inst (0004h)
Inst (0005h)
Inst (0004h)
Dummy cycle
FFh
00h
01h
02h
Note 1: Interrupt ag bit T0IF is sampled here (every Q1).
2: Interrupt latency = 4Tcy where Tcy = instruction cycle time.
3: CLKOUT is available only in RC oscillator mode.
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