PIC18C242 MICROCHIP [Microchip Technology], PIC18C242 Datasheet - Page 20

• Manufacturer Part Number: PIC18C242
• Description: High-Performance Microcontrollers with 10-Bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18CXX2
If the main oscillator is configured for HS-PLL mode, an
oscillator startup time (T
timeout (T
ms and allows the PLL to lock to the main oscillator fre-
FIGURE 2-10: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS WITH PLL)
If the main oscillator is configured in the RC, RCIO, EC
or ECIO modes, there is no oscillator startup timeout.
Operation will resume after eight cycles of the main
oscillator have been counted. A timing diagram indicat-
FIGURE 2-11: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)
DS39026B-page 20
Program Counter
Internal System
Program Counter
Note 1: T
(OSCCON<0>)
Note 1: RC oscillator mode assumed.
Internal System
(OSCCON<0>)
PLL Clock
T1OSI
OSC1
OSC2
T1OSI
Clock
OSC1
OSC2
Input
Clock
PLL
SCS
SCS
OST
) will occur. The PLL timeout is typically 2
= 1024T
PC
Q4
Q3
OSC
Q1
OST
T
(drawing not to scale).
OST
) plus an additional PLL
PC
Q4
T
PLL
Q1
Preliminary
PC + 2
T
OSC
1
T
1
OSC
T
T
2
1
quency. A timing diagram indicating the transition from
the Timer1 oscillator to the main oscillator for HS-PLL
mode is shown in Figure 2-10.
ing the transition from the Timer1 oscillator to the main
oscillator for RC, RCIO, EC and ECIO modes is shown
in Figure 2-11.
2
P
3
3
PC + 2
T
SCS
4
T
4
T
T
1
SCS
P
5
5
6
6
7
7
Q1 Q2 Q3 Q4
8
8
Q1 Q2 Q3
7/99 Microchip Technology Inc.
Q4 Q1 Q2 Q3
Q1 Q2
PC + 4
PC + 4
Q3
Q4
Q4