PIC18F6621-I/PT Microchip Technology Inc., PIC18F6621-I/PT Datasheet - Page 23

• Manufacturer Part Number: PIC18F6621-I/PT
• Description: 64 PIN, 64 KB FLASH, 3840 RAM, 52 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F6621-I/PT

• A/d Inputs: 12-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 1024 Bytes
• Input Output: 54
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 64-pin TQFP
• Programmable Memory: 64K Bytes
• Ram Size: 3.8K Bytes
• Speed: 40 MHz
• Timers: 2-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

2.0
2.1
The PIC18F6525/6621/8525/8621 devices can be
operated in twelve different oscillator modes. The user
can program four configuration bits (FOSC3, FOSC2,
FOSC1 and FOSC0) to select one of these eight
modes:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. ECIO+PLL
11. HS+SPLL
12. RCIO
2.2
In XT, LP, HS, HS+PLL or HS+SPLL Oscillator modes, a
crystal or ceramic resonator is connected to the OSC1
and OSC2 pins to establish oscillation. Figure 2-1 shows
the pin connections.
The PIC18F6525/6621/8525/8621 oscillator design
requires the use of a parallel cut crystal.
 2005 Microchip Technology Inc.
Note:
LP
XT
HS
RC
EC
ECIO
HS+PLL
RCIO
ECIO+SPLL External Clock with software
OSCILLATOR
CONFIGURATIONS
Oscillator Types
Crystal Oscillator/Ceramic
Resonators
Use of a series cut crystal may give a
frequency out of the crystal manufacturers
specifications.
enabled
with PLL enabled
pin enabled
with software control
Low-Power Crystal
Crystal/Resonator
High-Speed Crystal/Resonator
External Resistor/Capacitor
External Clock
External Clock with I/O pin
High-Speed Crystal/Resonator
External Resistor/Capacitor with
I/O pin enabled
controlled PLL
External Clock with PLL and I/O
High-Speed Crystal/Resonator
External Resistor/Capacitor with
I/O pin enabled
PIC18F6525/6621/8525/8621
FIGURE 2-1:
TABLE 2-1:
These values are for design guidance only.
See notes following this table.
Note 1:
Mode
Note 1: Higher capacitance increases the stability
HS
XT
C1
C2
2:
3:
2: When operating below 3V V
3: Since each resonator/crystal has its own
4 MHz
2 kHz
(1)
(1)
of the oscillator but also increases the
start-up time.
using certain ceramic resonators at any
voltage, it may be necessary to use high
gain HS mode, try a lower frequency
resonator or switch to a crystal oscillator.
characteristics, the user should consult the
resonator/crystal manufacturer for appro-
priate values of external components or
verify oscillator performance.
See Table 2-1 and Table 2-2 for
recommended values of C1 and C2.
A series resistor (R
AT strip cut crystals.
R
16.0 MHz
XTAL
R
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
F
S
Freq
varies with the oscillator mode chosen.
(2)
Resonators Used:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
OSC2
OSC1
Ranges Tested:
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
CONFIGURATION)
68-100 pF
15-68 pF
15-68 pF
10-68 pF
10-22 pF
PIC18F6X2X/8X2X
S
R
) may be required for
C1
F
(3)
16 MHz
DS39612B-page 21
8 MHz
Sleep
DD
68-100 pF
15-68 pF
15-68 pF
10-68 pF
10-22 pF
, or when
To
Internal
Logic
C2