PIC16F819 Microchip Technology Inc., PIC16F819 Datasheet - Page 36

• Manufacturer Part Number: PIC16F819
• Description: 18/20-pin Enhanced Flash Microcontrollers With Nanowatt Technology
• Manufacturer: Microchip Technology Inc.

PIC16F818/819
FIGURE 4-2:
TABLE 4-2:
DS39598E-page 34
Capacitor values are for design guidance only.
These capacitors were tested with the resonators
listed below for basic start-up and operation. These
values were not optimized.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
V
See the notes following this table for additional
information.
Note 1: See Table 4-2 for typical values of C1 and C2.
DD
Note:
Mode
HS
XT
and temperature range for the application.
2: A series resistor (R
3: R
C1
C2
Typical Capacitor Values Used:
(1)
(1)
between 2 M
When using resonators with frequencies
above 3.5 MHz, the use of HS mode rather
than XT mode is recommended. HS mode
may be used at any V
controller is rated. If HS is selected, it is
possible that the gain of the oscillator will
overdrive the resonator. Therefore, a
series resistor should be placed between
the OSC2 pin and the resonator. As a
good starting point, the recommended
value of R
F
16.0 MHz
2.0 MHz
4.0 MHz
8.0 MHz
varies with the resonator chosen (typically
455 kHz
R
RES
Freq
S (2)
CERAMIC RESONATORS (FOR
DESIGN GUIDANCE ONLY)
OSC1
OSC2
S
CERAMIC RESONATOR
OPERATION (HS OR XT
OSC CONFIGURATION)
is 330
to 10 M
S
) may be required.
R
OSC1
56 pF
47 pF
33 pF
27 pF
22 pF
F (3)
.
DD
PIC16F818/819
for which the
To Internal
Logic
Sleep
OSC2
56 pF
47 pF
33 pF
27 pF
22 pF
4.3
The ECIO Oscillator mode requires an external clock
source to be connected to the OSC1 pin. There is no
oscillator start-up time required after a Power-on Reset
or after an exit from Sleep mode.
In the ECIO Oscillator mode, the OSC2 pin becomes
an additional general purpose I/O pin. The I/O pin
becomes bit 6 of PORTA (RA6). Figure 4-3 shows the
pin connections for the ECIO Oscillator mode.
FIGURE 4-3:
Clock from
Ext. System
External Clock Input
RA6
EXTERNAL CLOCK INPUT
OPERATION
(ECIO CONFIGURATION)
 2004 Microchip Technology Inc.
OSC1/CLKI
I/O (OSC2)
PIC16F818/819