PIC16F737-I/SP Microchip Technology Inc., PIC16F737-I/SP Datasheet - Page 37

• Manufacturer Part Number: PIC16F737-I/SP
• Description: 28 PIN, 7 KB FLASH, 368 RAM, 25 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F737-I/SP

• A/d Inputs: 5-Channel, 8-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 25
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 7K Bytes
• Ram Size: 192 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

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
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 package types will also
affect the oscillation frequency, especially for low C
values. The user also needs to take into account varia-
tion 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
R
C
V
R
C
V
SS
EXT
EXT
SS
EXT
EXT
V
V
RC Oscillator
DD
DD
RA6
EXT
F
OSC
) and capacitor (C
/4
RC OSCILLATOR MODE
RCIO OSCILLATOR MODE
OSC1
OSC1
OSC2/CLKO
C
I/O (OSC2)
C
EXT
EXT
> 20 pF
> 20 pF
R
R
EXT
EXT
EXT
PIC16F7X7
PIC16F7X7
100 k
100 k
) values and the
Internal
Internal
Clock
Clock
EXT
4.5
The PIC16F7X7 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 six 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
• Two-Speed Start-up
• Fail-Safe Clock Monitor
These features are discussed in greater detail in
Section 15.0 “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 (page 38).
Note:
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).
PIC16F7X7
DS30498C-page 35