<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[msephd的专栏]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/msephd</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; msephd]]></copyright><item><title><![CDATA[TTL和CMOS电平总结(回答了什么是TTL和CMOS电平)]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/8076311</link><guid>https://blog.youkuaiyun.com/msephd/article/details/8076311</guid><author>msephd</author><pubDate>Tue, 16 Oct 2012 11:25:17 +0800</pubDate><description><![CDATA[注:鉴于很多电子初学者对什么是TTL电平,什么是CMOS电平不清楚.也不能了解CMOS电平与TTL电平的区别.特别在网上找到这篇TTL和CMOS电平总结.感谢作者的工作.

1，TTL电平(什么是TTL电平)： 
输出高电平>2.4V,输出低电平=2.0V，输入低电平<=0.8V，噪声容限是0.4V。

2，CMOS电平： 
1逻辑电平电压接近于电源电压，0逻辑电平接近于0V。而且具有]]></description><category></category></item><item><title><![CDATA[Ethernet  PHY and MAC]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7962554</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7962554</guid><author>msephd</author><pubDate>Mon, 10 Sep 2012 11:06:19 +0800</pubDate><description><![CDATA[以太网PHY和MAC对应OSI模型的两个层——物理层和数据链路层。
物理层定义了数据传送与接收所需要的电与光信号、线路状态、时钟基准、数据编码和电路等，并向数据链路层设备提供标准接口（RGMII / GMII / MII）。
数据链路层则提供寻址机构、数据帧的构建、数据差错检查、传送控制、向网络层提供标准的数据接口等功能。

问：以太网PHY是什么？ 
答：PHY是物理接口收发器，它实现]]></description><category></category></item><item><title><![CDATA[带眼镜的一定要看！一个眼镜批发商的话]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7907514</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7907514</guid><author>msephd</author><pubDate>Sat, 25 Aug 2012 19:39:44 +0800</pubDate><description><![CDATA[本人误入眼镜这行有十年了，从小零售商做到小批发商也有5年了，近来看到有人在网上搞宣传为自己开的网店骗人，因此想站出来揭发一下。


眼镜批发这行分眼镜片，眼镜框，隐形眼镜片，隐形眼镜药水四大类。


一，隐形眼镜药水的生产成本最低，整体利润最大，生产成本基本上都是包装的价格，里面的药水可能比生理盐水贵不了许多，你见过40元一瓶的生理盐水吗。但是这其中没有算上专利费用，检测费用，报批时的]]></description><category></category></item><item><title><![CDATA[extern usage of C language]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7859249</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7859249</guid><author>msephd</author><pubDate>Mon, 13 Aug 2012 11:08:01 +0800</pubDate><description><![CDATA[C支持4种存储类型说明符：
       extern  static register auto 
这些说明符告诉编译程序应该怎样保存有关变量。存储类型说明符放在其修饰的变量生明之前，其一般形式是：
    ① storage_specifiertype var_name;
*注* C89和C99均规定，typedef从造句方便上讲是存储类型说明符，而从通常的术语上讲不是存储类型说明符。]]></description><category></category></item><item><title><![CDATA[The Detailed explanation of __initdata macro in linux kernel]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7859233</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7859233</guid><author>msephd</author><pubDate>Mon, 13 Aug 2012 11:05:45 +0800</pubDate><description><![CDATA[The __init and __exit declarations are special kernel macrosdesigned to tell the kernel to flag these functions for special handling incases where they are compiled in statically rather than included]]></description><category></category></item><item><title><![CDATA[The Detailed explanation of __setup macro in linux kernel]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7859227</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7859227</guid><author>msephd</author><pubDate>Mon, 13 Aug 2012 11:03:37 +0800</pubDate><description><![CDATA[内核组件用__setup宏来注册关键字及相关联的处理函数，__setup宏在include/linux/init.h中定义，其原型如下：
__setup(string,function_handler)
#define __setup(str, fn)                             
\
       __setup_param(str, fn, fn, 0)]]></description><category></category></item><item><title><![CDATA[The flag analysis of struct termios]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7859204</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7859204</guid><author>msephd</author><pubDate>Mon, 13 Aug 2012 11:00:02 +0800</pubDate><description><![CDATA[struct termios {
       tcflag_t c_iflag;             /*input mode flags */
       tcflag_t c_oflag;            /*output mode flags */
       tcflag_tc_cflag;            /*control mode flags */]]></description><category></category></item><item><title><![CDATA[How to close firewall in Fedora]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7700069</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7700069</guid><author>msephd</author><pubDate>Thu, 28 Jun 2012 17:08:23 +0800</pubDate><description><![CDATA[valid atfer restart 
open： chkconfig iptables on 
close： chkconfig iptables off   or  /sbin/chkconfig --level 2345 iptables off

2)  valid immediately and invalide after restart 
 by service 
op]]></description><category></category></item><item><title><![CDATA[linux shell command usage]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7598961</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7598961</guid><author>msephd</author><pubDate>Thu, 24 May 2012 16:26:52 +0800</pubDate><description><![CDATA[1） 在linux下，如何比较两个目录下的文件（目录比较命令） 

     diff -r dir1 dir2 

2）source命令的作用
分类： bash 2006-04-21 15:32 6234人阅读 评论(2) 收藏 举报
source命令的作用就是用来执行一个脚本，那么：
source a.sh 同直接执行 ./a.sh 有什么不同呢，比如你在一个脚本里export]]></description><category></category></item><item><title><![CDATA[打工是最愚蠢的投资——李嘉诚在大梅沙的演讲~（讲的太给力了）]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7593744</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7593744</guid><author>msephd</author><pubDate>Wed, 23 May 2012 10:37:04 +0800</pubDate><description><![CDATA[很多人会认为打工并不是投资，强烈反对这种观念。其实打工才是最大最愚蠢的投资。 人生最宝贵的是什么？除了我们的青春还有什么更宝贵？很多人都抱怨我穷，我没钱想做生意又找不到资金。多么的可笑！其实在你身上就有着一座金山(无形资产)，只是你不敢承认。宁可埋没也不敢利用。宁可委委屈屈地帮人打工，把你的资产双手拱让给了你的老板。我们试想一下，有谁生下来上天就会送给他一大堆金钱的？问问李嘉诚吧。 我曾经问过我的]]></description><category></category></item><item><title><![CDATA[ARINC 653]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7546981</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7546981</guid><author>msephd</author><pubDate>Tue, 08 May 2012 17:06:07 +0800</pubDate><description><![CDATA[ARINC 653 is a standard Real Time Operating System (RTOS) interface for partitioning of computer resources in the time and space domains. The standard also specifies Appliation Program Interfaces (API]]></description><category></category></item><item><title><![CDATA[ASM  is A  kind of Sharp Knife for hacker]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7498310</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7498310</guid><author>msephd</author><pubDate>Wed, 25 Apr 2012 15:54:33 +0800</pubDate><description><![CDATA[------------------------------------------------------------------------------------]]></description><category></category></item><item><title><![CDATA[Introducing to The Study of Embeded Development from Ten Years Experiences]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7498117</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7498117</guid><author>msephd</author><pubDate>Wed, 25 Apr 2012 15:17:54 +0800</pubDate><description><![CDATA[一、嵌入式系统的概念  
     
     着重理解“嵌入”的概念    
主要从三个方面上来理解。  
     1、从硬件上，将基于CPU的处围器件，整合到CPU芯片内部，比如早期基于X86体系结构下的计算机，CPU只是有运算器和累加器的功能，一切芯片要造外部桥路来扩展实现，象串口之类的都是靠外部的16C550/2的串口控制器芯片实现，而目前的这种串口控制器芯片早已集成到CPU内部]]></description><category></category></item><item><title><![CDATA[There are only 900 months of all your life]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7497981</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7497981</guid><author>msephd</author><pubDate>Wed, 25 Apr 2012 14:47:20 +0800</pubDate><description><![CDATA[人生只有900个月 从未意识到 人生可以短暂到如此精确 事实上 你可以画一个30x30的表格 一张A4纸足够 每过一个月 就在一个格子里打钩 你全部的人生就在这张纸上…]]></description><category></category></item><item><title><![CDATA[How to Include ASM File and to Highlight Display in Source Insight]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7490098</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7490098</guid><author>msephd</author><pubDate>Mon, 23 Apr 2012 16:14:56 +0800</pubDate><description><![CDATA[做ARM嵌入式开发时，有时得整汇编代码，但在SIS里建立PROJECT并ADD TREE的时候，根据默认设置并不会把该TREE里面所有汇编文件都包含进来，默认只加了.inc和.asm后缀的， .s后缀的没有。而且用SIS打开.s的文件时，一片黑白没有色彩, 感觉回到DOS的EDIT时代里了。
      解决方法是在Options->Document Options里面，点左上的Document]]></description><category></category></item><item><title><![CDATA[The distinct interpretation of the $(),${} between make and shell]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7410498</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7410498</guid><author>msephd</author><pubDate>Fri, 30 Mar 2012 11:14:19 +0800</pubDate><description><![CDATA[1)  In make $() = ${}

    To substitute a variable's value, write a dolar sign followed by the name of the variable in parentheses or braces:

    either '$(foo)' or '${foo}' is a valid reference]]></description><category></category></item><item><title><![CDATA[Linux系统下Shell命令行快捷键实用技巧]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7403007</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7403007</guid><author>msephd</author><pubDate>Wed, 28 Mar 2012 15:09:09 +0800</pubDate><description><![CDATA[[摘要] 下文具体介绍了Linux系统下Shell命令行快捷键实用技巧.
        [关键字] Linux Shell 快捷键 实用技巧 　　
        # Ctrl + A - Go to the beginning of the line you are currently typing on

　　# Ctrl + E - Go to the end of the lin]]></description><category></category></item><item><title><![CDATA[华清远见教材目录]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7402784</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7402784</guid><author>msephd</author><pubDate>Wed, 28 Mar 2012 14:15:18 +0800</pubDate><description><![CDATA[http://www.farsight.com.cn/FarsightBooks/home.html]]></description><category></category></item><item><title><![CDATA[diff 命令输出格式说明]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7398488</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7398488</guid><author>msephd</author><pubDate>Tue, 27 Mar 2012 13:12:12 +0800</pubDate><description><![CDATA[diff 的输出格式：

change-command


---
> to-file-line
> to-file-line…

diff 命令的格式的使用方式如下：
diff from-file to-fille

如果按照输出的 change-command 去修改 from-file 则可以得到和 to-file 相同的档案内容

lar exmaple: 8a]]></description><category></category></item><item><title><![CDATA[How to uncompress files with suffix tar.xz]]></title><link>https://blog.youkuaiyun.com/msephd/article/details/7384047</link><guid>https://blog.youkuaiyun.com/msephd/article/details/7384047</guid><author>msephd</author><pubDate>Thu, 22 Mar 2012 17:22:39 +0800</pubDate><description><![CDATA[$xz -d ***.tar.xz
$tar -xvf  ***.tar]]></description><category></category></item></channel></rss>