The USB (Universal Serial Bus) specification requires a connected USB device to present a load to the host or hub of no greater than 10 µF in parallel with 44Ω, including the effects of any bypass capacitance visible through the device’s voltage regu…

The popular USB interface can charge a portable device while transferring data. But for high-capacity batteries, the 500-mA output current of USB hosts and powered hubs greatly extends the charging time. (Unpowered USB hubs supply no more than 100 mA…

LDO current regulator for power LED Challenge You've got a power LED? Great! Build a flash light! What does the spec say? "Voltage: 3.6 .. 3.8 V, power 3 W." Okay. This means that it draws some 800 mA. Three mignon cells give 4.5 V for at least…

Power OFF and ON USB device in linux (ubuntu) http://loginroot.com/power-off-and-on-usb-device-in-linux-ubuntu/ There are two methods of doing this. So first method is for kernels after 2.6.32, and second for older ones. To view kernel version, simpl…

参考: http://www.siongboon.com/projects/2013-07-08_raspberry_pi/index.html Raspberry Pi         Get started with Raspberry Pi (RPi), a step by step approach to get your Raspberry Pi with low level electronics hardware control. Make simple, step by step…

In my previous blog on "How to evaluate a transimpedance amplifier, part 1", we looked at the OPA857 performance, but didn’t go in depth in explaining how those measurements were taken.  Now that we’ve have established a reference, let’s work th…

norflash 烧写 (7) Nor Flash指令 Nor Flash 的命令经常用于烧写数据到Nor Flash . flinfo  打印Flash存储器的信息,并列出所有Sector. flinfo  N 单独打Flash存储器N Block的信息.(在有多块Nor Flash时使用) 使用范例: [u-boot@MINI2440]# flinfo Bank # 1: SST: 1x SST39VF1601 (2MB) Size: 2 MB in 32 Sectors Sector St…

About this project This project was developed after I had to find out that controlling my RGB ambient light with the normal infrared remote control was complicated and not reliable. Within a few months I build this solution that enabled controlling m…

Transistor Tutorial Summary Transistor Tutorial Summary Bipolar Junction Transistor Tutorial We can summarise this transistors tutorial section as follows: The Bipolar Junction Transistor (BJT) is a three layer device constructed form two semiconduct…

ARM上的linux如何实现无线网卡的冷插拔和热插拔 fulinux 凌云实验室 1. 冷插拔 如果在系统上电之前就将RT2070/RT3070芯片的无线网卡(以下简称wlan)插上,即冷插拔.我们通过分析系统启动流程过程中的运行的脚本,将启动wlan的脚本加入其中,就可以实现自动运行wlan.. 系统启动后的第一个进程/sbin/init.init进程最主要的功能就是准备软件执行的环境,包括系统的主机名.网络配置.语系处理.文件系统格式以及其他服务的启动等.而所有的操作都会通过init的配置文…

SB2.0是在1.0的基础上于2000年提出来的,在1.0的基础上曾加了480Mbps的数据传输率.USB2.0具有以下的优点: 1.每个USB系统中有一个主机,通过级联的方式连接多个外部设备,最多可以支持127个设备,且支持设备同时操作. 2.支持热插拔 3.应用广泛,可支持多种低速,全速,高速设备 Low speed data rate:1.5Mbps Full speed data rate:12Mbps High speed data rate:480Mbps USB OTG标准在完全兼…

(8) USB 操作指令 指令 功能 usb reset 初始化USB控制器 usb stop [f] 关闭USB控制器 usb tree 已连接的USB设备树 usb info [dev] 显示USB设备[dev]的信息 usb storage 显示已连接的USB存储设备 usb dev [dev] 显示和设置当前USB存储设备 usb part [dev] 显示USB存储设备[dev]的分区信息 usb read addr blk# cnt 读取USB存储设备数据 在所有的命令使用前,必须先…

A Multi-Position Joint Particle Filtering Method for Vehicle Localization in Urban Area 城市车辆定位的多位置联合粒子滤波方法 Shuxia Gu, Zhiyu Xiang*, Yi Zhang and Qi Qian 张宁 Abstract—Robust localization is a prerequisite for autonomous vehicles. Traditional visual loc…

A transition between the states only occurs on the rising edge of TCK, and each state has a different name. The two vertical columns with seven states each represent the Instruction Path and the Data Path. The data registers operate in the states who…

建议看本文档时结合nginx源代码. 1.1   什么是内存池?为什么要引入内存池? 内存池实质上是接替OS进行内存管理.应用程序申请内存时不再与OS打交道.而是从内存池中申请内存或者释放内存到内存池.因此.内存池在实现的过程中,必定有一部分操作时从OS中申请内存.或者释放内存到OS.例如以下图所看到的: 图1 内存池的引入可有效解决两个问题: (1) 减少应用程序与OS之间进行频繁内存和释放的系统调用,进而减少程序执行期间在两个空间的切换,提升了程序执行效率: (2)内存池可依据应用特性组织内…

备注 考虑到 Heap 的特性,很容易想到将其用作排序的用处,为了提高效率需要适当的改进一下,如:in place remove 和 in place move down. 代码 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace DataStuctureStudy.Sorts { class He…

背景 Heap 可以用来实现优先级队列,也可以用来做堆排序,本文简单的做个介绍. Heap 规则 是一个完全二叉树,隐含的意思是:他是平衡的.使用数组进行存储也是连续的. 给定的任意节点,该节点小于等于其父亲节点,大于他们的孩子节点. 基础知识 对于一个完全二叉树,如果将其存储到数组中,给定父节点的索引为:x,则: left child's index is:2*x + 1. right child's index is:2*x + 2. root's index is:0. 说明:上面的公式很…

The classic LM317 adjustable-output linear voltage regulator offers a relatively high, if package-dependent, current-handling capability. In addition, the LM317 features current limiting and thermal-overload protection. With the addition of a few com…

You've probably heard the baleful reports. The number of college students majoring in the humanities is plummeting, according to a big study released last month by the American Academy of Arts & Sciences. The news has provoked a flood of high-minded…

转:http://www.360doc.com/content/10/0827/13/496343_49168699.shtml 获取帮助环境变量与相关指令U-boot的使用网络命令Nand Flash操作指令内存/寄存器操作指令Nor Flash指令USB 操作指令SD卡(MMC)指令FAT文件系统指令系统引导指令EEPROM 读写指令设置和读取RTC指令脚本运行指令系统重启指令下载与烧写 1) 通过SD卡烧入Nand Flash: 2) 通过U盘烧入Nor Flash 3) 通过TFTP服务…

内存池的目的就是管理内存,使回收内存可以自动化一些. ngx_palloc.h /* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_PALLOC_H_INCLUDED_ #define _NGX_PALLOC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> // 内存池界定小内存与大内存的边界值的最大值. /* * N…

Abstract Semantic word spaces have been very useful but cannot express the meaning of longer phrases in a principled way. 语义词空间是非常有用的,但它不能有原则地表达较长短语的意义. Further progress towards understanding compositionality in tasks such as sentiment detection requ…

不知道ZSet(有序集合)的看官们,可以翻阅我的上一篇文章: 小白也能看懂的REDIS教学基础篇--朋友面试被SKIPLIST跳跃表拦住了 书接上回,话说我朋友小A童鞋,终于面世通过加入了一家公司.这个公司待遇比较丰厚,而且离小A住的地方也比较近,最让小A中意还是有个肯带他的大佬.小A对这份工作非常满意.时间一天一天过去,某个周末,小A来找我家吃蹭饭.在饭桌上小A给我分享了他上星期的一次事故经历. 上个星期,他们公司出了比较严重的一个事故,一个导出报表的后台服务拖垮了报表数据服务,导致很多查询该…

The difference between the request time and the current time is too large. 阿里云oss上传图片的时候报错如上, 解决办法,把系统时间自动同步成对应的时区的时间.…

解决:efi usb device has been blocked by the current security policy 问题描述:U盘装系统或者其他操作时,是因为BIOS安全策略,出现上述错误无法进入后续步骤. 解决方法:按F2(Fn+F2)进入BIOS,在secure Boot 中security选择disable.解决! 延伸(可不读): 黑苹果安装过程中选择UEFI+GPT格式问题! (1)选择了UEFI启动的出现上述问题,可以按以上解决. (2)安装黑苹果过程中磁盘管理抹盘过…

昨天,在测试新的数据库时,迁移表遇到了这个问题.现在记录一下解决方案. 1.在配置文件中添加关闭严格模式的配置:sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 2.在配置文件中添加使用独立表空间的配置:innodb_file_per_table=1 3.在数据库中执行:SHOW GLOBAL VARIABLES LIKE '%innodb_file%'; +--------------------------+-----------+ |…

catalogue . 引言 . Device Class Definition for Human Interface Devices (HID) . USB HID Report Descriptors . arduino USB Keyboard definition . USB Host Shield for Arduino分类 . USB Host Shield for Arduino datasheet . USB Host Library Rev.2.0 . USB Keyboar…

Linux就这个范儿 第15章 七种武器  linux 同步IO: sync.fsync与fdatasync   Linux中的内存大页面huge page/large page  David Cutler  Linux读写内存数据的三种方式 台湾作家林清玄在接受记者采访的时候,如此评价自己30多年写作生涯:“第一个十年我才华横溢,‘贼光闪现’,令周边黯然失色:第二个十年,我终于‘宝光现形’,不再去抢风头,反而与身边的美丽相得益彰:进入第三个十年,繁华落尽见真醇,我进入了‘醇光初现’的阶段,真正…

Bypass the China Firewall Methods November 16th, 2012Posted in , Tech With their assortment of techniques to prohibit access to websites they do not like, China is probably the country where the “Site not found” errors are most common, with the possi…

http://www.circuitsathome.com/mcu/pic_vpp_limiter VOUT = 2.5V * ( 1 + 24/10 ) = 2.5 * 3.4 = 8.5V Newer PIC18s, such as my current favorite – PIC18F26K20, don’t like to be programmed with 12V. The datasheet maximum is 9V. Older Microchip programmers/d…