16F84A Microchip Technology, 16F84A Datasheet - Page 22

• Manufacturer Part Number: 16F84A
• Description: 18-pin Enhanced Flash/EEPROM 8-Bit Microcontroller
• Manufacturer: Microchip Technology

PIC16F84A
6.2
6.2.1
The PIC16F84A can be operated in four different
oscillator
configuration bits (FOSC1 and FOSC0) to select one of
these four modes:
• LP
• XT
• HS
• RC
6.2.2
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 6-2).
FIGURE 6-2:
The PIC16F84A oscillator design requires 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 XT, LP or HS modes, the device
can have an external clock source to drive the
OSC1/CLKIN pin (Figure 6-3).
FIGURE 6-3:
DS35007A-page 22
Note1:
Clock from
ext. system
2:
3:
C1
C2
Oscillator Configurations
CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
OSCILLATOR TYPES
(1)
(1)
modes. The
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
See Table 6-1 for recommended values of
C1 and C2.
A series resistor (RS) may be required for
AT strip cut crystals.
RF varies with the crystal chosen.
XTAL
RS
Open
(2)
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP OSC
CONFIGURATION)
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
OSC1
OSC2
user
OSC1
OSC2
RF
(3)
can
PIC16FXX
SLEEP
program
PIC16FXX
To
internal
logic
Preliminary
two
TABLE 6-1
TABLE 6-2
Ranges Tested:
Note :
Resonators Tested:
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
10.0 MHz
Note :
Crystals Tested:
32.768 kHz Epson C-001R32.768K-A
100 kHz
200 kHz
1.0 MHz
2.0 MHz
4.0 MHz
10.0 MHz
Mode
HS
XT
LP
Mode
HS
XT
None of the resonators had built-in capacitors.
Recommended values of C1 and C2 are identical to
the ranges tested table.
Higher capacitance increases the stability of the
oscillator but also increases the start-up time.
These values are for design guidance only. Since
each resonator has its own characteristics, the user
should consult the resonator manufacturer for the
appropriate values of external components.
Higher capacitance increases the stability of
oscillator but also increases the start-up time.
These values are for design guidance only. Rs may
be required in HS mode as well as XT mode to
avoid overdriving crystals with low drive level spec-
ification. Since each crystal has its own characteris-
tics, the user should consult the crystal
manufacturer for appropriate values of external
components.
For V
200 kHz
100 kHz
DD
10 MHz
32 kHz
2 MHz
4 MHz
4 MHz
Panasonic EFO-A455K04B
Murata Erie CSA2.00MG
Murata Erie CSA4.00MG
Murata Erie CSA8.00MT
Murata Erie CSA10.00MTZ
Epson C-2 100.00 KC-P
STD XTL 200.000 KHz
ECS ECS-10-13-2
ECS ECS-20-S-2
ECS ECS-40-S-4
ECS ECS-100-S-4
Freq
10.0 MHz
> 4.5V, C1 = C2
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
Freq
CAPACITOR SELECTION
FOR CERAMIC RESONATORS
CAPACITOR SELECTION
FOR CRYSTAL OSCILLATOR
100 - 150 pF
68 - 100 pF
1998 Microchip Technology Inc.
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
OSC1/C1
47 - 100 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
OSC1/C1
30 pF is recommended.
100 - 150 pF
68 - 100 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
47 - 100 pF
OSC2/C2
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
OSC2/C2
20 PPM
20 PPM
20 PPM
50 PPM
50 PPM
50 PPM
50 PPM
0.3%
0.5%
0.5%
0.5%
0.5%