參數(shù)資料
型號: PIC16C556
廠商: Microchip Technology Inc.
英文描述: EPROM-Based 8-Bit CMOS Microcontroller(每個I/O口有25mA驅(qū)動/吸收電流,微控制器)
中文描述: 存儲器為基礎(chǔ)的8位CMOS微控制器(每個的I / O口有25毫安驅(qū)動/吸收電流,微控制器)
文件頁數(shù): 36/104頁
文件大?。?/td> 697K
代理商: PIC16C556
PIC16C55X
DS40143A-page 36
Preliminary
1996 Microchip Technology Inc.
7.2.3
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
Either a pre-packaged oscillator can be used or a sim-
ple 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 circuits can be
used; one with series resonance, or one with parallel
resonance.
Figure 7-4 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
feedback
for
potentiometers bias the 74AS04 in the linear region.
This could be used for external oscillator designs.
stability.
resistor provides the
The
10 k
FIGURE 7-4:
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
Figure 7-5 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
resistors provide the negative feedback to bias
the inverters in their linear region.
°
FIGURE 7-5:
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
20 pF
+5V
20 pF
10k
4.7k
10k
74AS04
XTAL
10k
74AS04
PIC16C55X
CLK
IN
To other
Devices
330
74AS04
74AS04
PIC16C55X
CLK
IN
To other
Devices
XTAL
330
74AS04
0.1
μ
F
7.2.4
RC OSCILLATOR
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 (Rext) and capacitor (Cext) values, and the
operating temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal
process
parameter
variation.
difference in lead frame capacitance between package
types will also affect the oscillation frequency,
especially for low Cext values. The user also needs to
take into account variation due to tolerance of external
R and C components used. Figure 7-6 shows how the
R/C combination is connected to the PIC16C55X. For
Rext values below 2.2 k
, the oscillator operation may
become unstable, or stop completely. For very high
Rext values (e.g., 1 M
sensitive to noise, humidity and leakage. Thus, we
recommend to keep Rext between 3 k
Although the oscillator will operate with no external
capacitor (Cext = 0 pF), we recommend using values
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 oscillator frequency, divided by 4, is available on
the OSC2/CLKOUT pin, and can be used for test
purposes or to synchronize other logic (Figure 3-2 for
waveform).
Furthermore,
the
), the oscillator becomes
and 100 k
.
FIGURE 7-6:
RC OSCILLATOR MODE
OSC2/CLKOUT
Cext
Rext
V
DD
PIC16C55X
OSC1
Fosc/4
Internal Clock
V
DD
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PIC16C558/JW 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16C558-04/P 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16C558-04/P 制造商:Microchip Technology Inc 功能描述:IC 8-BIT CMOS MCU
PIC16C558-04/SO 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
PIC16C558-04/SS 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT