PIC18F87J10 FAMILY
DS39663F-page 30
2009 Microchip Technology Inc.
2.6
External Oscillator Pins
Many microcontrollers have options for at least two
oscillators: a high-frequency primary oscillator and a
low-frequency
secondary
oscillator
(refer
to
The oscillator circuit should be placed on the same
side of the board as the device. Place the oscillator
circuit close to the respective oscillator pins with no
more than 0.5 inch (12 mm) between the circuit
components and the pins. The load capacitors should
be placed next to the oscillator itself, on the same side
of the board.
Use a grounded copper pour around the oscillator
circuit to isolate it from surrounding circuits. The
grounded copper pour should be routed directly to the
MCU ground. Do not run any signal traces or power
traces inside the ground pour. Also, if using a
two-sided board, avoid any traces on the other side of
the board where the crystal is placed. A suggested
layout is shown in Figure 2-4.
For additional information and design guidance on
oscillator circuits, please refer to these Microchip
Application Notes, available at the corporate web site
(www.microchip.com):
AN826, “Crystal Oscillator Basics and Crystal
Selection for rfPIC and PICmicro Devices”
AN849, “Basic PICmicro Oscillator Design”
AN943, “Practical PICmicro Oscillator Analysis
and Design”
AN949, “Making Your Oscillator Work”
FIGURE 2-4:
SUGGESTED PLACEMENT
OF THE OSCILLATOR
CIRCUIT
2.7
Unused I/Os
Unused I/O pins should be configured as outputs and
driven to a logic low state. Alternatively, connect a 1 k
to 10 k resistor to VSS on unused pins and drive the
output to logic low.
13
Main Oscillator
Guard Ring
Guard Trace
Secondary
Oscillator
14
15
16
17
18
19
20
相关PDF资料
PIC24FV32KA302-I/SO MCU 32KB FLASH 2KB RAM 28-SOIC
PIC24HJ64GP204-I/ML IC PIC MCU FLASH 64K 44-QFN
SFW27R-2STE1 SFW27R-2STE1-FFC/FPC CONN
PIC24F16KA302-I/SP MCU 16KB FLASH 2KB RAM 28-SPDIP
PIC18LF45J11-I/ML IC PIC MCU FLASH 32K 2V 44-QFN
PIC24F32KA302-I/SO MCU 32KB FLASH 2KB RAM 28-SOIC
PIC32MX120F032D-I/TL IC MCU 32BIT 32KB FLASH 44-VTLA
PIC18F45J11-I/ML IC PIC MCU FLASH 32K 2V 44-QFN
相关代理商/技术参数
PIC18F66J15T-I/PT 功能描述:8位微控制器 -MCU 96 KB FL 4 KB RAM 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
PIC18F66J16-I/PT 功能描述:8位微控制器 -MCU 96KB FL 3936b RAM 10 MIPS 51 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
PIC18F66J16T-I/PT 功能描述:8位微控制器 -MCU 96KB Flash 3936 bytesRAM 51I/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
PIC18F66J50-I/PT 功能描述:8位微控制器 -MCU 64KB FLSH 3936Bs RAM USB 2.0 nanoWatt 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
PIC18F66J50T-I/PT 功能描述:8位微控制器 -MCU 64KB FLSH 3936Bs RAM USB 2.0 nanoWatt 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
PIC18F66J55-I/PT 功能描述:8位微控制器 -MCU 96KB FLSH 3936Bs RAM USB 2.0 nanoWatt 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
PIC18F66J55T-I/PT 功能描述:8位微控制器 -MCU 96KB FLSH 3936Bs RAM USB 2.0 nanoWatt 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
PIC18F66J60-I/PT 功能描述:8位微控制器 -MCU 64KB FL 12KB RAM 10BASE-T 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