PIC16C432T-I/SS Microchip Technology, PIC16C432T-I/SS Datasheet - Page 48

• Manufacturer Part Number: PIC16C432T-I/SS
• Description: IC MCU CMOS 8BIT 20MHZ 2K 20SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C432T-I/SS

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: LIN (Local Interconnect Network)
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: OTP
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SSOP
• For Use With: AC164029 - MODULE SKT PROMATEII 20DIP/SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

PIC16C432
9.2.3
Either a prepackaged oscillator can be used, or a sim-
ple oscillator circuit with TTL gates can be built. Pre-
packaged 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 circuits can be used: one with
series resonance, or one with parallel resonance.
Figure 9-3 shows implementation of a parallel resonant
oscillator circuit. The circuit is designed to use the
fundamental frequency of the crystal. The 74AS04
inverter performs the 180 phase shift that a parallel
oscillator requires. The 4.7 k
negative
potentiometers bias the 74AS04 in the linear region.
This could be used for external oscillator designs.
FIGURE 9-3:
Figure 9-4 shows a series resonant oscillator circuit.
This circuit is also designed to use the fundamental
frequency of the crystal. The inverter performs a 180
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 9-4:
DS41140B-page 46
74AS04
330
10k
+5V
20 pF
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
feedback
10k
0.1 mF
XTAL
74AS04
XTAL
4.7k
74AS04
20 pF
330
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
for
10k
74AS04
stability.
74AS04
resistor provides the
To Other
Devices
To other
Devices
PIC16C432
The
CLKIN
PIC16C432
CLKIN
10 k
Preliminary
9.2.4
For timing insensitive applications, the “RC” device
option offers 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
process
difference in lead frame capacitance between package
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 9-5 shows how the
R/C combination is connected to the PIC16C432. For
R
become unstable, or stop completely. For very high
R
sensitive to noise, humidity and leakage. Thus, it is
recommended to keep R
Although the oscillator will operate with no external
capacitor (C
above 20 pF for noise and stability reasons. With no or
small external capacitance, the oscillation frequency
can vary dramatically due to changes in external
capacitances, such as PCB trace capacitance, or
package lead frame capacitance.
The variation is larger for larger R (since leakage cur-
rent variation will affect RC frequency more for large R)
and for smaller C (since variation of input capacitance
will affect RC frequency more).
See Section 2.0 for variation of oscillator frequency due
to V
frequency variation due to operating temperature for
given R, C, and V
The oscillator frequency, divided by 4, is available on
the OSC2/CLKOUT pin and can be used for test pur-
poses, or to synchronize other logic (see Figure 4-2 for
waveform).
FIGURE 9-5:
EXT
EXT
C
R
V
EXT
EXT
DD
DD
values below 2.2 k , the oscillator operation may
V
values (i.e., 1 M ), the oscillator becomes
DD
for given R
parameter
EXT
RC OSCILLATOR
EXT
) and capacitor (C
F
= 0 pF), we recommend using values
OSC
DD
EXT
/4
values.
EXT
RC OSCILLATOR MODE
OSC1
variation.
values. The user also needs to
OSC2/CLKOUT
EXT
/C
2002 Microchip Technology Inc.
between 3 k and 100 k .
EXT
PIC16C432
EXT
values, as well as
Furthermore,
) values, and the
Internal Clock
the