PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 27

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

If the main oscillator is configured for HS4 (PLL) mode,
an oscillator start-up time (T
time-out (T
2 ms and allows the PLL to lock to the main oscillator
frequency. A timing diagram indicating the transition
from the Timer1 oscillator to the main oscillator for HS4
mode is shown in Figure 2-9.
FIGURE 2-9:
FIGURE 2-10: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)
 2000 Microchip Technology Inc.
Program Counter
Note 1:
Note 1:
Program Counter
Internal System
(OSCCON<0>)
(OSCCON<0>)
Internal System
PLL Clock
T1OSI
T1OSI
OSC1
OSC2
OSC1
OSC2
Clock
PLL
Clock
Input
SCS
SCS
T
RC oscillator mode assumed.
OST
) will occur. The PLL time-out is typically
= 1024T
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS WITH PLL)
Q4
PC
Q3
OSC
(drawing not to scale).
Q1
OST
T
OST
) plus an additional PLL
PC
Q4
T
PLL
Advanced Information
Q1
PC + 2
T
OSC
1
T
1
OSC
T
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 indicat-
ing the transition from the Timer1 oscillator to the main
oscillator for RC, RCIO, EC and ECIO modes is shown
in Figure 2-10.
T
1
2
2
P
3
3
PC + 2
T
4
SCS
T
4
T
T
SCS
1
5
P
5
6
6
7
7
Q1 Q2 Q3 Q4
8
8
PIC18CXX8
Q1 Q2 Q3
Q4 Q1 Q2 Q3
DS30475A-page 27
Q1 Q2
PC + 4
PC + 4
Q3
Q4
Q4