PIC12C672T-04I/SM Microchip Technology, PIC12C672T-04I/SM Datasheet - Page 55

• Manufacturer Part Number: PIC12C672T-04I/SM
• Description: IC MCU OTP 2KX14 A/D 8-SOIJ
• Manufacturer: Microchip Technology
• Series: PIC® 12Cr

Specifications of PIC12C672T-04I/SM

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 5
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: OTP
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 4x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (5.3mm Width), 8-SOP, 8-SOEIAJ
• For Use With: XLT08SO-1 - SOCKET TRANSITION 8SOIC 150/208AC164312 - MODULE SKT FOR PM3 16SOIC309-1048 - ADAPTER 8-SOIC TO 8-DIP309-1047 - ADAPTER 8-SOIC TO 8-DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

9.2.3
Either a pre-packaged oscillator or a simple oscillator
circuit with TTL gates can be used as an external
crystal oscillator circuit. 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 parallel
resonance or one with series resonance.
Figure 9-3
resonant oscillator circuit. The circuit is 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
provides the negative feedback for stability. The 10 k
potentiometers bias the 74AS04 in the linear region.
This circuit 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-
degree phase shift in a series resonant oscillator
circuit. The 330
feedback to bias the inverters in their linear region.
FIGURE 9-4:
1999 Microchip Technology Inc.
74AS04
330
10k
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
+5V
20 pF
shows implementation
10k
0.1 F
XTAL
74AS04
XTAL
4.7k
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
74AS04
20 pF
330
resistors provide the negative
10k
74AS04
74AS04
To Other
Devices
To Other
Devices
of
PIC12C67X
CLKIN
PIC12C67X
CLKIN
a parallel
resistor
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 PIC12C67X. For R
2.2 k , the oscillator operation may become unstable
or stop completely. For very high R
(i.e., 1 M ), the oscillator becomes sensitive to noise,
humidity and leakage. Thus, we recommend keeping
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
current variation will affect RC frequency more for
large R) and for smaller C (since variation of input
capacitance will affect RC frequency more).
FIGURE 9-5:
EXT
C
V
R
EXT
SS
EXT
between 3 k and 100 k .
V
DD
F
EXTERNAL RC OSCILLATOR
OSC
parameter
EXT
EXT
/4
) and capacitor (C
= 0 pF), we recommend using values
EXTERNAL RC OSCILLATOR
MODE
EXT
variation.
values. The user also needs to
PIC12C67X
OSC1
OSC2/CLKOUT
N
EXT
Furthermore,
) values, and the
DS30561B-page 55
EXT
PIC12C67X
values below
EXT
Internal
clock
values
the