參數(shù)資料
型號： PIC16C56A-20I/JW
元件分類： 微控制器/微處理器
英文描述： 8-BIT, UVPROM, 20 MHz, RISC MICROCONTROLLER, CDIP18
封裝： 0.300 INCH, WINDOWED, CERDIP-18
文件頁數(shù)： 87/158頁
文件大小： 1194K
代理商： PIC16C56A-20I/JW
PIC16C5X
DS30453C-page 34
Preliminary
2000 Microchip Technology Inc.
7.2.3
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
Either a prepackaged oscillator or a simple oscillator
circuit with TTL gates can be used as an external crys-
tal oscillator circuit. Prepackaged oscillators provide a
wide
operating
range
and
better
stability.
A
well-designed crystal oscillator will provide good perfor-
mance with TTL gates. Two types of crystal oscillator
circuits can be used: one with parallel resonance or
one with series resonance.
Figure 7-5 shows implementation of a parallel resonant
oscillator circuit. The circuit is designed to use the fun-
damental frequency of the crystal. The 74AS04 inverter
performs the 180-degree phase shift that a parallel
oscillator requires. The 4.7 k
resistor provides the
negative feedback for stability. The 10 k
potentiome-
ters bias the 74AS04 in the linear region. This circuit
could be used for external oscillator designs.
FIGURE 7-5:
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
(USING XT, HS OR LP
OSCILLATOR MODE)
This circuit is also designed to use the fundamental fre-
quency of the crystal. The inverter performs a
180-degree phase shift in a series resonant oscillator
circuit. The 330
resistors provide the negative feed-
back to bias the inverters in their linear region.
Note:
If you change from one device to another
device, please verify oscillator characteris-
tics in your application.
20 pF
+5V
20 pF
10k
4.7k
10k
74AS04
XTAL
10k
74AS04
PIC16C5X
OSC1
To Other
Devices
OSC2
100k
FIGURE 7-6:
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
(USING XT, HS OR LP
OSCILLATOR MODE)
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 resis-
tor (REXT) and capacitor (CEXT) values, and the operat-
ing temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal pro-
cess parameter variation. Furthermore, the 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 compo-
nents used.
Figure 7-7 shows how the R/C combination is con-
nected to the PIC16C5X. 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
) the oscillator becomes sensitive to noise,
humidity and leakage. Thus, we recommend keeping
REXT between 3 k
and 100 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 pack-
age lead frame capacitance.
Note:
If you change from one device to another
device, please verify oscillator characteris-
tics in your application.
330
74AS04
PIC16C5X
OSC1
To Other
Devices
XTAL
330
74AS04
0.1
F
OSC2
100k
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參數(shù)描述
PIC16C56A20SO 制造商:MICROCHIP 功能描述:New
PIC16C56A-40/P 功能描述:8位微控制器 -MCU 1.5KB 25 RAM 12 I/O 40MHz PDIP18 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(fēng)格:SMD/SMT
PIC16C56A-40/SO 功能描述:8位微控制器 -MCU 1.5KB 25 RAM 12 I/O 40MHz SOIC18 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(fēng)格:SMD/SMT
PIC16C56A-40/SS 功能描述:8位微控制器 -MCU 1.5KB 25 RAM 12 I/O 40MHz SSOP20 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(fēng)格:SMD/SMT
PIC16C56AT-04/SO 功能描述:8位微控制器 -MCU 1.5KB 25 RAM 12 I/O 4 MHz SOIC18 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(fēng)格:SMD/SMT
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