PIC12F609/615/12HV609/615
3.3.3
LP, XT, HS MODES
Note 1: Quartz crystal characteristics vary according
The LP, XT and HS modes support the use of quartz
crystal resonators or ceramic resonators connected to
OSC1 and OSC2 (Figure 3-3). The mode selects a low,
medium or high gain setting of the internal
inverter-amplifier to support various resonator types
and speed.
to type, package and manufacturer. The
user should consult the manufacturer data
sheets for specifications and recommended
application.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
LP Oscillator mode selects the lowest gain setting of
the internal inverter-amplifier. LP mode current
consumption is the least of the three modes. This mode
is designed to drive only 32.768 kHz tuning-fork type
crystals (watch crystals).
3: For oscillator design assistance, reference
the following Microchip Applications Notes:
• AN826, “Crystal Oscillator Basics and
Crystal Selection for rfPIC® and PIC®
Devices” (DS00826)
• AN849, “Basic PIC® Oscillator Design”
(DS00849)
• AN943, “Practical PIC® Oscillator
XT Oscillator mode selects the intermediate gain
setting of the internal inverter-amplifier. XT mode
current consumption is the medium of the three modes.
This mode is best suited to drive resonators with a
medium drive level specification.
Analysis and Design” (DS00943)
HS Oscillator mode selects the highest gain setting of
the internal inverter-amplifier. HS mode current
consumption is the highest of the three modes. This
mode is best suited for resonators that require a high
drive setting.
• AN949, “Making Your Oscillator Work”
(DS00949)
FIGURE 3-4:
CERAMIC RESONATOR
OPERATION
Figure 3-3 and Figure 3-4 show typical circuits for
quartz crystal and ceramic resonators, respectively.
(XT OR HS MODE)
PIC® MCU
FIGURE 3-3:
QUARTZ CRYSTAL
OPERATION (LP, XT OR
HS MODE)
OSC1/CLKIN
C1
To Internal
Logic
PIC® MCU
(3)
(2)
RP
RF
Sleep
OSC1/CLKIN
C1
To Internal
Logic
OSC2/CLKOUT
(1)
C2
RS
Ceramic
Quartz
Crystal
(2)
Resonator
Sleep
RF
Note 1: A series resistor (RS) may be required for
ceramic resonators with low drive level.
OSC2/CLKOUT
(1)
C2
RS
2: The value of RF varies with the Oscillator mode
selected (typically between 2 MΩ to 10 MΩ).
Note 1: A series resistor (RS) may be required for
3: An additional parallel feedback resistor (RP)
may be required for proper ceramic resonator
operation.
quartz crystals with low drive level.
2: The value of RF varies with the Oscillator mode
selected (typically between 2 MΩ to 10 MΩ).
© 2006 Microchip Technology Inc.
Preliminary
DS41302A-page 27
MICROCHIP [ MICROCHIP ]
