参数资料
型号: PIC18F2431-E/MM
厂商: Microchip Technology
文件页数: 46/119页
文件大小: 0K
描述: IC MCU FLASH 8KX16 28QFN
标准包装: 61
系列: PIC® 18F
核心处理器: PIC
芯体尺寸: 8-位
速度: 40MHz
连通性: I²C,SPI,UART/USART
外围设备: 欠压检测/复位,LVD,电源控制 PWM,QEI,POR,PWM,WDT
输入/输出数: 24
程序存储器容量: 16KB(8K x 16)
程序存储器类型: 闪存
EEPROM 大小: 256 x 8
RAM 容量: 768 x 8
电压 - 电源 (Vcc/Vdd): 4.2 V ~ 5.5 V
数据转换器: A/D 5x10b
振荡器型: 内部
工作温度: -40°C ~ 125°C
封装/外壳: 28-VQFN 裸露焊盘
包装: 管件
其它名称: PIC18F2431-E/ML
PIC18F2431-E/ML-ND
PIC18F2331/2431/4331/4431
DS39616D-page 32
2010 Microchip Technology Inc.
3.6
Internal Oscillator Block
The PIC18F2331/2431/4331/4431 devices include an
internal oscillator block, which generates two different
clock signals; either can be used as the system’s clock
source. This can eliminate the need for external
oscillator circuits on the OSC1 and/or OSC2 pins.
The main output (INTOSC) is an 8 MHz clock source,
which can be used to directly drive the system clock. It
also drives a postscaler, which can provide a range of
clock frequencies from 125 kHz to 4 MHz. The
INTOSC output is enabled when a system clock
frequency from 125 kHz to 8 MHz is selected.
The other clock source is the internal RC oscillator
(INTRC), which provides a 31 kHz output. The INTRC
oscillator is enabled by selecting the internal oscillator
block as the system clock source, or when any of the
following are enabled:
Power-up Timer
Fail-Safe Clock Monitor
Watchdog Timer
Two-Speed Start-up
These features are discussed in greater detail in
The clock source frequency (INTOSC direct, INTRC
direct or INTOSC postscaler) is selected by configuring
the IRCF bits of the OSCCON register (Register 3-2).
3.6.1
INTIO MODES
Using the internal oscillator as the clock source can
eliminate the need for up to two external oscillator pins,
which can then be used for digital I/O. Two distinct
configurations are available:
In INTIO1 mode, the OSC2 pin outputs FOSC/4,
while OSC1 functions as RA7 for digital input and
output.
In INTIO2 mode, OSC1 functions as RA7 and
OSC2 functions as RA6, both for digital input and
output.
3.6.2
INTRC OUTPUT FREQUENCY
The internal oscillator block is calibrated at the factory
to produce an INTOSC output frequency of 8.0 MHz.
This changes the frequency of the INTRC source from
its nominal 31.25 kHz. Peripherals and features that
depend on the INTRC source will be affected by this
shift in frequency.
3.6.3
OSCTUNE REGISTER
The internal oscillator’s output has been calibrated at the
factory, but can be adjusted in the user’s application.
This is done by writing to the OSCTUNE register
(Register 3-1). Each increment may adjust the FRC
frequency by varying amounts and may not be mono-
tonic. The next closest frequency may be multiple steps
apart.
When the OSCTUNE register is modified, the INTOSC
and INTRC frequencies will begin shifting to the new
frequency. Code execution continues during this shift.
There is no indication that the shift has occurred. Oper-
ation of features that depend on the INTRC clock
source frequency, such as the WDT, Fail-Safe Clock
Monitor and peripherals, will also be affected by the
change in frequency.
3.6.4
INTOSC FREQUENCY DRIFT
The factory calibrates the internal oscillator block out-
put (INTOSC) for 8 MHz. This frequency, however, may
drift as the VDD or temperature changes, which can
affect the controller operation in a variety of ways.
The INTOSC frequency can be adjusted by modifying
the value in the OSCTUNE register. This has no effect
on the INTRC clock source frequency.
Tuning the INTOSC source requires knowing when to
make an adjustment, in which direction it should be
made, and in some cases, how large a change is
needed. Three compensation techniques are discussed
in
, but other techniques
may be used.
相关PDF资料
PDF描述
DSPIC33FJ16GS504-E/PT IC DSPIC MCU/DSP 16K 44-TQFP
DSPIC30F3011-20E/P IC DSPIC MCU/DSP 24K 40DIP
PIC16F74-E/P IC MCU FLASH 4KX14 A/D 40DIP
PIC16LC71-04I/P IC MCU OTP 1KX14 A/D 18DIP
PIC16C621T-20/SS IC MCU OTP 1KX14 COMP 20SSOP
相关代理商/技术参数
参数描述
PIC18F2431-I/ML 功能描述:8位微控制器 -MCU 16KB 768 RAM 22 I/O 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
PIC18F2431-I/MM 功能描述:8位微控制器 -MCU 16 KB FL 768 RAM 22 I/O 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
PIC18F2431-I/SO 功能描述:8位微控制器 -MCU 16KB 768 RAM 22 I/O 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
PIC18F2431-I/SO 制造商:Microchip Technology Inc 功能描述:IC 8BIT FLASH MCU 18F2431 SOIC28
PIC18F2431-I/SP 功能描述:8位微控制器 -MCU 16KB 768 RAM 22 I/O 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