PIC16F818-I/P Microchip Technology, PIC16F818-I/P Datasheet - Page 37

• Manufacturer Part Number: PIC16F818-I/P
• Description: IC MCU FLASH 1KX14 18-DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F818-I/P

• Program Memory Type: FLASH
• Program Memory Size: 1.75KB (1K x 14)
• Package / Case: 18-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• 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: 16
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ACICE0202 - ADAPTER MPLABICE 18P 300 MILAC164010 - MODULE SKT PROMATEII DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4.4
For timing insensitive applications, the “RC” and
“RCIO” device options offer additional cost savings.
The RC oscillator frequency is a function of the supply
voltage, the resistor (R
values and the operating temperature. In addition to
this, the oscillator frequency will vary from unit to unit
due to normal manufacturing variation. Furthermore,
the difference in lead frame capacitance between pack-
age types will also affect the oscillation frequency,
especially for low C
take into account variation due to tolerance of external
R and C components used. Figure 4-4 shows how the
R/C combination is connected.
In the RC 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.
FIGURE 4-4:
The RCIO Oscillator mode (Figure 4-5) functions like
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 4-5:
 2004 Microchip Technology Inc.
Recommended values: 3 k
Recommended values: 3 k
C
C
V
V
R
R
EXT
EXT
SS
SS
EXT
EXT
V
V
DD
DD
RC Oscillator
RA6
F
OSC
EXT
/4
RC OSCILLATOR MODE
RCIO OSCILLATOR MODE
values. The user also needs to
C
C
OSC1
OSC1
OSC2/CLKO
I/O (OSC2)
EXT
EXT
EXT
> 20 pF
> 20 pF
) and capacitor (C
R
R
EXT
EXT
100 k
100 k
PIC16F818/819
PIC16F818/819
Internal
Internal
Clock
Clock
EXT
)
4.5
The PIC16F818/819 devices include an internal
oscillator block which generates two different clock
signals; either can be used as the system’s clock
source. This can eliminate the need for external
oscillator circuits on the OSC1 and/or OSC2 pins.
The main output (INTOSC) is an 8 MHz clock source
which can be used to directly drive the system clock. It
also drives the INTOSC postscaler which can provide a
range of clock frequencies from 125 kHz to 4 MHz.
The other clock source is the internal RC oscillator
(INTRC) which provides a 31.25 kHz (32 s nominal
period) output. The INTRC oscillator is enabled by
selecting the INTRC as the system clock source or
when any of the following are enabled:
• Power-up Timer
• Watchdog Timer
These features are discussed in greater detail in
Section 12.0 “Special Features of the CPU”.
The clock source frequency (INTOSC direct, INTRC
direct or INTOSC postscaler) is selected by configuring
the IRCF bits of the OSCCON register (Register 4-2).
4.5.1
Using the internal oscillator as the clock source can
eliminate the need for up to two external oscillator pins,
which can then be used for digital I/O. Two distinct
configurations are available:
• In INTIO1 mode, the OSC2 pin outputs F
• In INTIO2 mode, OSC1 functions as RA7 and
Note:
while OSC1 functions as RA7 for digital input and
output.
OSC2 functions as RA6, both for digital input and
output.
Internal Oscillator Block
Throughout this data sheet, when referring
specifically to a generic clock source, the
term “INTRC” may also be used to refer to
the clock modes using the internal
oscillator block. This is regardless of
whether the actual frequency used is
INTOSC (8 MHz), the INTOSC postscaler
or INTRC (31.25 kHz).
INTRC MODES
PIC16F818/819
DS39598E-page 35
OSC
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