PIC18F6620 Microchip, PIC18F6620 Datasheet - Page 29

• Manufacturer Part Number: PIC18F6620
• Description: Microcontroller
• Manufacturer: Microchip

If the main oscillator is configured for HS-PLL mode, an
oscillator start-up time (T
time-out (T
2 ms and allows the PLL to lock to the main oscillator
FIGURE 2-10:
If the main oscillator is configured in the RC, RCIO, EC
or ECIO modes, there is no oscillator start-up time-out.
Operation will resume after eight cycles of the main
oscillator have been counted. A timing diagram,
FIGURE 2-11:
 2004 Microchip Technology Inc.
Program Counter
Note 1: T
Internal System
Note 1: RC Oscillator mode assumed.
(OSCCON<0>)
Internal System
(OSCCON<0>)
PLL Clock
Program
Counter
OST
T1OSI
OSC1
OSC2
Clock
T1OSI
PLL
OSC1
OSC2
SCS
Clock
Input
SCS
= 1024 T
), will occur. The PLL time-out is typically
PIC18F6520/8520/6620/8620/6720/8720
OSC
Q4
PC
Q3
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS WITH PLL)
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)
(drawing not to scale).
OST
Q1
), plus an additional PLL
T
OST
PC
Q4
T
PLL
Q1
T
PC + 2
OSC
T
1
1
OSC
T
frequency. A timing diagram, indicating the transition
from the Timer1 oscillator to the main oscillator for
HS-PLL mode, is shown in Figure 2-10.
indicating the transition from the Timer1 oscillator to the
main oscillator for RC, RCIO, EC and ECIO modes, is
shown in Figure 2-11.
T
1
2
P
2
3
3
PC + 2
4
T
SCS
T
T
4
SCS
T
1
5
P
5
6
6
7
7
8
Q1 Q2 Q3 Q4
8
Q1 Q2 Q3
Q4 Q1 Q2 Q3
DS39609B-page 27
Q1 Q2
PC + 4
PC + 4
Q3
Q4
Q4