PIC16C63A/65B/73B/74B
FIGURE 13-1:
CRYSTAL/CERAMIC
RESONATOROPERATION
(HS, XT OR LP
13.2 Oscillator Configurations
13.2.1 OSCILLATOR TYPES
OSC CONFIGURATION)
The PIC16CXX can be operated in four different oscil-
lator modes. The user can program two configuration
bits (FOSC1 and FOSC0) to select one of these four
modes:
OSC1
To internal
logic
C1
C2
• LP
• XT
• HS
• RC
Low Power Crystal
XTAL
OSC2
SLEEP
PIC16CXX
RF
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
RS
(Note 1)
13.2.2
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
See Table 13-1 and Table 13-2 for recommended values of C1
and C2.
Note 1: A series resistor may be required for AT strip cut crystals.
In XT, LP, or HS modes, a crystal or ceramic resonator
is connected to the OSC1/CLKIN and OSC2/CLKOUT
pins to establish oscillation (Figure 13-1). The
PIC16CXX oscillator design requires the use of a par-
allel cut crystal. Use of a series cut crystal may give a
frequency out of the crystal manufacturers specifica-
tions. When in XT, LP or HS modes, the device can
have an external clock source to drive the OSC1/
CLKIN pin (Figure 13-2). See the PICmicro™ Mid-
Range MCU Reference Manual (DS33023) for details
on building an external oscillator.
FIGURE 13-2:
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR
LP OSC CONFIGURATION)
OSC1
Clock from
ext. system
PIC16CXX
OSC2
Open
DS30605C-page 86
2000 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
