PIC16F872-I/SS Microchip Technology, PIC16F872-I/SS Datasheet - Page 41

• Manufacturer Part Number: PIC16F872-I/SS
• Description: IC MCU FLASH 2KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F872-I/SS

• Core Size: 8-Bit
• Program Memory Size: 3.5KB (2K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 64Byte
• Ram Memory Size: 128Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: I2C, SPI, SSP
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 3 bit
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details

2.3.5
1997 Microchip Technology Inc.
External Crystal Oscillator Circuit for Device Clock
Sometimes more than one device needs to be clocked from a single crystal. Since Microchip
does not recommend connecting other logic to the PICmicro’s internal oscillator circuit, an exter-
nal crystal oscillator circuit is recommended. Each device will then have an external clock source,
and the number of devices that can be driven will depend on the buffer drive capability. This circuit
is also useful when more than one device (PICmicro) needs to operate synchronously to each
other.
Either a prepackaged oscillator can be used or a simple oscillator circuit with TTL gates can be
built. Prepackaged oscillators provide a wide operating range and better stability. A well-designed
crystal oscillator will provide good performance with TTL gates. Two types of crystal oscillator cir-
cuits can be used; one with series resonance, or one with parallel resonance.
Figure 2-4
designed to use the fundamental frequency of the crystal. The 74AS04 inverter performs the
180-degree phase shift that a parallel oscillator requires. The 4.7 k resistor provides the nega-
tive feedback for stability. The 10 k potentiometer biases the 74AS04 in the linear region.
Figure 2-4: External Parallel Resonant Crystal Oscillator Circuit
Figure 2-5
the fundamental frequency of the crystal. The inverter performs a 180-degree phase shift in a
series resonant oscillator circuit. The 330 k resistors provide the negative feedback to bias the
inverters in their linear region.
Figure 2-5: External Series Resonant Crystal Oscillator Circuit
When the device is clocked from an external clock source (as in
the microcontroller’s oscillator must be configured for LP, XT or HS mode
shows an external series resonant oscillator circuit. This circuit is also designed to use
shows implementation of an external parallel resonant oscillator circuit. The circuit is
74AS04
330 k
10 k
+5V
20 pF
10k
0.1 F
XTAL
74AS04
XTAL
4.7 k
Section 2. Oscillator
20 pF
74AS04
330 k
10 k
74AS04
74AS04
To Other
Devices
To Other
Devices
PIC16CXXX
CLKIN
Figure 2-4
PIC16CXXX
CLKIN
(Figure
DS31002A-page 2-11
or
Figure
2-3).
2-5) then
2