12F508 Microchip Technology, 12F508 Datasheet - Page 43

• Manufacturer Part Number: 12F508
• Description: Search -----> PIC12F508
• Manufacturer: Microchip Technology

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7.2
7.2.1
The PIC12F508/509/16F505 devices can be operated
in up to six different oscillator modes. The user can
program up to three configuration bits (FOSC<1:0>
[PIC12F508/509], FOSC<2:0> [PIC16F505]). To select
one of these modes:
• LP:
• XT:
• HS:
• INTRC: Internal 4 MHz Oscillator
• EXTRC: External Resistor/Capacitor
• EC:
7.2.2
In HS (PIC16F505), XT or LP modes, a crystal or
ceramic resonator is connected to the (GP5/RB5)/
OSC1/(CLKIN) and (GP4/RB4)/OSC2/(CLKOUT) pins
to establish oscillation (Figure 7-1). The PIC12F508/
509/16F505 oscillator designs require the use of a
parallel cut crystal. Use of a series cut crystal may give
a frequency out of the crystal manufacturers
specifications. When in HS (PIC16F505), XT or LP
modes, the device can have an external clock source
drive the (GP5/RB5)/OSC1/CLKIN pin (Figure 7-2).
© 2005 Microchip Technology Inc.
Note 1: This device has been designed to per-
2: The user should verify that the device
Oscillator Configurations
Crystal/Resonator
(PIC16F505 only)
External High-Speed Clock Input
(PIC16F505 only)
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
Low-Power Crystal
High-Speed Crystal/Resonator
OSCILLATOR TYPES
form to the parameters of its data sheet.
It has been tested to an electrical
specification designed to determine its
conformance with these parameters.
Due to process differences in the
manufacture of this device, this device
may have different performance charac-
teristics than its earlier version. These
differences may cause this device to
perform differently in your application
than the earlier version of this device.
oscillator
expected. Adjusting the loading capacitor
values and/or the Oscillator mode may
be required.
starts
and
performs
as
Preliminary
PIC12F508/509/16F505
FIGURE 7-1:
FIGURE 7-2:
TABLE 7-1:
Note 1:
Clock from
ext. system
Note 1:
HS
Type
Osc
XT
(2)
2:
C2
C1
2:
3:
(1)
(1)
Resonator
These values are for design guidance
only. Since each resonator has its own
characteristics, the user should consult
the resonator manufacturer for
appropriate values of external
components.
PIC16F505 only.
4.0 MHz
See Capacitor Selection tables for
recommended values of C1 and C2.
A series resistor (RS) may be required for AT
strip cut crystals.
RF approx. value = 10 M .
16 MHz
Freq.
Open
RS
XTAL
(2)
CAPACITOR SELECTION FOR
CERAMIC RESONATORS –
PIC12F508/509/16F505
OSC2
OSC1
CRYSTAL OPERATION
(OR CERAMIC
RESONATOR)
(HS, XT OR LP OSC
CONFIGURATION)
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR
LP OSC
CONFIGURATION)
Cap. Range
10-47 pF
30 pF
OSC2
OSC1
C1
RF
(3)
PIC12F508/509
DS41236B-page 41
PIC16F505
PIC12F508/509
PIC16F505
Cap. Range
10-47 pF
To internal
Sleep
30 pF
(1)
C2
logic