PIC18F2331-E/ML MICROCHIP [Microchip Technology], PIC18F2331-E/ML Datasheet - Page 31

• Manufacturer Part Number: PIC18F2331-E/ML
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
• Manufacturer: MICROCHIP [Microchip Technology]

3.4
The EC and ECIO Oscillator modes require 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 EC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic.
Oscillator mode.
FIGURE 3-4:
The ECIO Oscillator mode functions like the EC mode,
except that the OSC2 pin becomes an additional
general purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6).
for the ECIO Oscillator mode.
FIGURE 3-5:
 2010 Microchip Technology Inc.
Clock from
Ext. System
Clock from
Ext. System
Figure 3-4
External Clock Input
F
OSC
RA6
Figure 3-5
shows the pin connections for the EC
/4
EXTERNAL CLOCK INPUT
OPERATION
(EC CONFIGURATION)
EXTERNAL CLOCK INPUT
OPERATION
(ECIO CONFIGURATION)
shows the pin connections
OSC1/CLKI
OSC2/CLKO
OSC1/CLKI
I/O (OSC2)
PIC18FXXXX
PIC18FXXXX
PIC18F2331/2431/4331/4431
3.5
For timing-insensitive applications, the “RC” and “RCIO”
device options offer additional cost savings. The actual
oscillator frequency is a function of several factors:
• Supply voltage
• Values of the external resistor (R
• Operating temperature
Given the same device, operating voltage and tempera-
ture, and component values, there will also be unit-to-unit
frequency variations. These are due to factors, such as:
• Normal manufacturing variation
• Difference in lead frame capacitance between
• Variations within the tolerance of limits of R
In the RC Oscillator mode
frequency divided by 4 is available on the OSC2 pin.
This signal may be used for test purposes or to
synchronize other logic.
FIGURE 3-6:
The RCIO Oscillator mode
the RC mode, except that the OSC2 pin becomes an
additional general purpose I/O pin. The I/O pin
becomes bit 6 of PORTA (RA6).
FIGURE 3-7:
Recommended values: 3 k  R
Recommended values: 3 k  R
(C
package types (especially for low C
and C
C
C
V
V
R
R
EXT
EXT
SS
SS
EXT
EXT
EXT
V
V
)
EXT
DD
DD
RC Oscillator
RA6
F
OSC
/4
RC OSCILLATOR MODE
RCIO OSCILLATOR MODE
OSC1
C
OSC1
C
OSC2/CLKO
I/O (OSC2)
EXT
EXT
(Figure
(Figure
> 20 pF
> 20 pF
EXT
EXT
EXT
 100 k
 100 k
3-6), the oscillator
3-7) functions like
DS39616D-page 31
PIC18FXXXX
EXT
PIC18FXXXX
) and capacitor
values)
Internal
Internal
Clock
Clock
EXT