参数资料
型号: ST72C334N4B3XXX
厂商: STMICROELECTRONICS
元件分类: 微控制器/微处理器
英文描述: 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDIP56
封装: 0.600 INCH, PLASTIC, SDIP-56
文件页数: 78/153页
文件大小: 2235K
代理商: ST72C334N4B3XXX
ST72334J/N, ST72314J/N, ST72124J
30/153
9.3 MULTI-OSCILLATOR (MO)
The main clock of the ST7 can be generated by
four different source types coming from the multi-
oscillator block:
s
an external source
s
4 crystal or ceramic resonator oscillators
s
an external RC oscillator
s
an internal high frequency RC oscillator
Each oscillator is optimized for a given frequency
range in terms of consumption and is selectable
through the option byte. The associated hardware
configuration are shown in Table 3. Refer to the
electrical characteristics section for more details.
External Clock Source
In this external clock mode, a clock signal (square,
sinus or triangle) with ~50% duty cycle has to drive
the OSC1 pin while the OSC2 pin is tied to ground.
Crystal/Ceramic Oscillators
This family of oscillators has the advantage of pro-
ducing a very accurate rate on the main clock of
the ST7. The selection within a list of 4 oscillators
with different frequency ranges has to be done by
option byte in order to reduce consumption. In this
mode of the multi-oscillator, the resonator and the
load capacitors have to be placed as close as pos-
sible to the oscillator pins in order to minimize out-
put distortion and start-up stabilization time. The
loading capacitance values must be adjusted ac-
cording to the selected oscillator.
These oscillators are not stopped during the
RESET phase to avoid losing time in the oscillator
start-up phase.
External RC Oscillator
This oscillator allows a low cost solution for the
main clock of the ST7 using only an external resis-
tor and an external capacitor. The frequency of the
external RC oscillator (in the range of some MHz.)
is fixed by the resistor and the capacitor values.
Consequently in this MO mode, the accuracy of
the clock is directly linked to the accuracy of the
discrete components. The corresponding formula
is fOSC=4/(REXCEX)
Internal RC Oscillator
The internal RC oscillator mode is based on the
same principle as the external RC oscillator includ-
ing the resistance and the capacitance of the de-
vice. This mode is the most cost effective one with
the drawback of a lower frequency accuracy. Its
frequency is in the range of several MHz.
In this mode, the two oscillator pins have to be tied
to ground.
Table 3. ST7 Clock Sources
Hardware Configuration
Ex
terna
l
Cloc
k
Cr
ystal/
Ceram
ic
Re
sona
tors
Ex
ternal
RC
O
scilla
tor
Inte
rnal
R
C
Os
cillato
r
OSC1
OSC2
EXTERNAL
ST7
SOURCE
OSC1
OSC2
LOAD
CAPACITORS
ST7
CL2
CL1
OSC1
OSC2
ST7
CEX
REX
OSC1
OSC2
ST7
相关PDF资料
PDF描述
ST72321BAR6T7/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP64
ST72321BR6T7/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP64
ST72321BAR7TC/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP64
ST72321BJ6T3/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
ST72321BJ6T6/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
相关代理商/技术参数
参数描述
ST72C334N4B6 功能描述:8位微控制器 -MCU Flash 16K SPI/SCI RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72C334N4T3 功能描述:8位微控制器 -MCU Flash 16K SPI/SCI RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72C334N4T6 功能描述:8位微控制器 -MCU Flash 16K SPI/SCI RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72C334N4T6TR 制造商:STMicroelectronics 功能描述:MCU 8BIT ST7 CISC 16KB FLASH 3.3V/5V 64TQFP - Tape and Reel
ST72C8F64-A05AS 制造商:STEC Inc 功能描述:512MB,ECC,UB,PC3200 - Bulk