PIC16HV785 Microchip Technology Inc., PIC16HV785 Datasheet - Page 27

• Manufacturer Part Number: PIC16HV785
• Description: 20-pin Flash-based 8-bit Cmos Microcontroller
• Manufacturer: Microchip Technology Inc.

3.3.3
The LP, XT and HS modes support the use of quartz
crystal resonators or ceramic resonators connected to
the OSC1 and OSC2 pins (Figure 3-1). The mode
selects a low, medium or high gain setting of the inter-
nal inverter-amplifier to support various resonator
types and speed.
LP Oscillator mode selects the lowest gain setting of
the internal inverter-amplifier. LP mode current con-
sumption is the least of the three modes. This mode is
best suited to drive resonators with a low drive level
specification, for example, tuning fork type crystals.
XT Oscillator mode selects the intermediate gain set-
ting 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, for example, AT-cut quartz
crystal resonators.
HS Oscillator mode selects the highest gain setting of
the internal inverter-amplifier. HS mode current con-
sumption is the highest of the three modes. This mode
is best suited for resonators that require a high drive
setting, for example, AT-cut quartz crystal resonators or
ceramic resonators.
Figure 3-3 and Figure 3-4 show typical circuits for
quartz crystal and ceramic resonators, respectively.
FIGURE 3-3:
© 2006 Microchip Technology Inc.
Note 1: Quartz
Note 1: A series resistor (R
2: Always verify oscillator performance over
C1
2: The value of R
C2
LP, XT, HS MODES
according to type, package and manufac-
turer. The user should consult the manu-
facturer data sheets for specifications
and recommended application.
the V
expected for the application.
quartz crystals with low drive level.
mode selected (typically between 2 M
10 M
Quartz
Crystal
R
DD
S
.
(1)
OSC1
OSC2
and temperature range that is
crystal
QUARTZ CRYSTAL
OPERATION (LP, XT OR
HS MODE)
F
varies with the Oscillator
R
S
F
characteristics
PIC16F785/HV785
(2)
) may be required for
To Internal
Logic
Sleep
vary
to
Preliminary
FIGURE 3-4:
TABLE 3-2:
XT
HS
Note:
Mode
Note 1: A series resistor (R
C1
PIC16F785/HV785
C2 Ceramic
2: The value of R
3: An additional parallel feedback resistor (R
Resonator
These values are for design guidance
only. See notes following this table.
ceramic resonators with low drive level.
mode selected (typically between 2 M
10 M
may be required for proper ceramic resonator
operation (typical value 1 M ).
16.0 MHz
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
Freq.
CERAMIC RESONATORS
R
.
P (3)
R
OSC1
OSC2
S (1)
CERAMIC RESONATOR
OPERATION
(XT OR HS MODE)
OSC1 (C1)
68-100 pF
F
15-68 pF
10-68 pF
15-68 pF
10-22 pF
varies with the Oscillator
R
PIC16F785/HV785
S
F (2)
) may be required for
DS41249D-page 25
OSC2 (C2)
68-100 pF
To Internal
Logic
15-68 pF
10-68 pF
15-68 pF
10-22 pF
Sleep
P
to
)