PIC18F4550-I/P Microchip Technology Inc., PIC18F4550-I/P Datasheet - Page 27

• Manufacturer Part Number: PIC18F4550-I/P
• Description: 40 PIN, 32 KB FLASH, 2048 RAM, FS-USB 2.0
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F4550-I/P

• A/d Inputs: 13-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 12 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 34
• Interface: I2C/SPI/UART/USART/USB
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 40-pin PDIP
• Programmable Memory: 32K Bytes
• Ram Size: 2K Bytes
• Speed: 48 MHz
• Timers: 1-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

2.2.2
In HS, HSPLL, XT and XTPLL Oscillator modes, a
crystal or ceramic resonator is connected to the OSC1
and OSC2 pins to establish oscillation. Figure 2-2
shows the pin connections.
The oscillator design requires the use of a parallel cut
crystal.
FIGURE 2-2:
TABLE 2-1:
© 2006 Microchip Technology Inc.
Capacitor values are for design guidance only.
These capacitors were tested with the resonators
listed below for basic start-up and operation. These
values are 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 Table 2-2 for additional
information.
Note 1: See Table 2-1 and Table 2-2 for initial values of
Note:
DD
Mode
HS
XT
and temperature range for the application.
C1
C2
2: A series resistor (R
3: R
(1)
(1)
Typical Capacitor Values Used:
C1 and C2.
strip cut crystals.
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
Use of a series cut crystal may give a fre-
quency out of the crystal manufacturer’s
specifications.
F
16.0 MHz
varies with the oscillator mode chosen.
XTAL
R
4.0 MHz
8.0 MHz
S
Freq
(2)
Resonators Used:
OSC2
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
OSC1
16.0 MHz
CRYSTAL/CERAMIC
RESONATOR OPERATION
(XT, HS OR HSPLL
CONFIGURATION)
4.0 MHz
8.0 MHz
S
) may be required for AT
OSC1
33 pF
27 pF
22 pF
R
F
(3)
PIC18FXXXX
Sleep
OSC2
33 pF
27 pF
22 pF
PIC18F2455/2550/4455/4550
To
Internal
Logic
Preliminary
TABLE 2-2:
An internal postscaler allows users to select a clock
frequency other than that of the crystal or resonator.
Frequency division is determined by the CPUDIV
Configuration bits. Users may select a clock frequency
of the oscillator frequency, or 1/2, 1/3 or 1/4 of the
frequency.
An external clock may also be used when the micro-
controller is in HS Oscillator mode. In this case, the
OSC2/CLKO pin is left open (Figure 2-3).
Capacitor values are for design guidance only.
These capacitors were tested with the crystals listed
below for basic start-up and operation. These values
are 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.
Osc Type
DD
Note 1: Higher capacitance increases the stability
HS
XT
and temperature range for the application.
2: When operating below 3V V
3: Since each resonator/crystal has its own
4: Rs may be required to avoid overdriving
5: Always verify oscillator performance over
of oscillator but also increases the
start-up time.
using certain ceramic resonators at any
voltage, it may be necessary to use the
HS mode or switch to a crystal oscillator.
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate
components.
crystals with low drive level specification.
the V
expected for the application.
20 MHz
Crystal
4 MHz
4 MHz
8 MHz
Freq
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
DD
Crystals Used:
and temperature range that is
20 MHz
4 MHz
8 MHz
Typical Capacitor Values
values
27 pF
27 pF
22 pF
15 pF
C1
Tested:
DS39632C-page 25
of
DD
, or when
27 pF
27 pF
22 pF
15 pF
external
C2