标签: lan

KOYUELEC光与电子提供AMAZINGIC晶焱科技IP Camera LAN Port ESD/Lightning保护方案 AMAZINGIC晶焱科技电话0755-82574660、82542001 电子通信产品在设计之初，就要事先考虑因ESD/Lightning引发损坏电子元器件的问题。由于从设计到终端客户手中，通常会执行静电放电（ESD）和雷击（Lightning）验证，Lightning可能对芯片造成严重破坏，从而会给厂商带来比较大的损失。因而，研发人员的设计对Lightning的等防护设计需要更加重视。 在一些学校、银行特殊场所，为了保证所在环境师生的安全、记录金融系统的实时画面，绝大多数都会安装IPC（IP Camera）设备。IPC是结合传统摄像机与网络技术所产生的新一代摄像机，它可以将影像通过Internet传到某一位置的远端设备，且远端用户在不需要其它软件的情况下，通过网络浏览器即可实时监控其影音；授权用户还可以控制摄像机云台镜头的动作和系统配置。IPC产品如果因ESD或Lightning的设计不佳，不仅影响设备生产企业的产品合格率，而且也造成终端客户的使用感受，这些问题直接影响产品在市场的品牌形象和地位，所以ESD和Lightning防护设计是电子产品设计中不忽视的环节。 一、ESD会带来哪些危害 摩尔于上世纪60年代发表的杂志中提出，随着时间的推进半导体芯片上所集成的晶体管的数量以指数增长；我们所见的产品演变过程是最好的例子，比如电脑从台式机演变成笔记本型电脑，手持大哥大也演变成6英寸的智能手机终端，不仅是个头上的差异，而且功能和产品性能不知提升了多少；受益于先进的光刻设备带动芯片制造行业，厂家可以在同等大小的晶圆上设计更多的晶体管。IC制程越先进，意味着晶体管极间的距离越小，当然受ESD的抗扰度也会越弱。当设备受到外界ESD脉冲的干扰，如果进入敏感电路则会引起设备出现信息读取错误造成电路故障。 二、现有ESD防护方案中的不足 目前现有的ESD防护设计方案中，也存在其它不足。除了ESD的防护设计，也要注意EOS（Electrical Over Stress 电气过应力）；为了便于接线，室外IPC设备大多通过POE供电，其网络和电源一同铺设在网线槽中；户外设备除了自然界的雷击（Lightning）会造成EOS，市电的波动所形成EOS也会对设备产生影响。ESD和EOS的测试标准分别对应IEC61000-4-2和IEC61000-4-5,相较于ESD的测试波形，EOS测试波形具有持续时间长、破坏能力强的特点（图1），所以在同样电压条件下EOS对芯片的损坏更为严重，再者IPC设备大多数存在于户外，这也是为什么IPC设计会模拟雷击浪涌测试的原因。 图1. ESD和EOS差异 三、LAN 口ESD和Lightning的防护 在IPC产品中LAN为常用性外设接口，选用TVS器件需要了解Lightning参数IPP (Peak Pulse Current) (tp=8/20ms)。针对RJ45二次侧的TVS应用，晶焱科技推出了 AZ1513-04S 针对Line-GND共模抑制方案，该产品为为SOT23-6L封装，集成了4路的IO和1路电源的保护，同时具有ESD和EOS低钳位电压特点（图3）；针对Line-Line 差模抑制方案，推出了SOT23-6L封装产品 AZ1603-02S ，在PCB Layout时轻松匹配差分对的阻抗。10/100/1000M网络的信号传输测试过程中，同样对TVS器件的寄生电容要求极高， AZ1513-04S 和 AZ1603-02S 超低寄生电容参数如附表1，兼顾不同IPC设备与主机间长缆线通信对于寄生容值的冗余要求。 图2. LAN口防护方案 图3. AZ1513-04S 浪涌和TLP测试 LAN口的防雷击设计对PCB 布局要求非常高，除了满足网络变压器一次侧与二次侧间的间距要求、差分对阻抗要求，在TVS的PCB Layout需要注意信号线走向先要经过TVS，且线路越短越好，这样，当外界的ESD和EOS突波来临时能更快速启动TVS，以达到泄放电流的目的。 总结，通常IPC产品在网络变压器一次侧会安装大电流的防雷击器件，但存在钳位电压太高的问题，其中一部分能量通过初级与次级的分布电容耦合到后级电路，从而造成产品损坏；当差分线间形成差模电压时，能量是会通过网络变压器的初级线圈耦合到次级，如不通过TVS泄放多余电流，会造成PHY芯片的损坏，网络变压器二次侧的防护显得更为重要。目前可以看到IPC厂商常规测试标准有±6kV CM（共模测试电压） / ±3.5kV DM（差模测试电压），模拟雷击实验以满足产品在特定场所抵抗雷击能力，降低环境因素造成的产品故，从而节约维修成本且更好的维护品牌口碑。 Parts No. Package Capacitance(pF) Vrwm(V) Channel Vcl_ESD@8kV(V) Vcl_EOS@Ipp(V) Ipp(A) AZ1513-04S SOT23-6L 2 3.3 4 7.5 10 30 AZ1603-02S SOT23-6L 0.9 3.3 4 10 11 18 附表1

Today's fiber-optic connectors have the amazing mechanical precision that allows low-loss mated pairs, especially considering that single-mode fiber has an optical core of about 9 microns in diameter. Two of these cores, from opposing fibers, must be aligned with almost-perfect mechanical precision to affect the least amount of optical loss.   Positive contact and angled polish keep losses and reflections to a minimum. Of course, this small core size means that the slightest speck of dust on the single-mode core can introduce disastrously high levels of loss, so absolute cleanliness (cleaning the end faces of the connector ferrules) is a must every time a connection is made.     It was not always this good. Quite a few years ago, optical fiber networking was becoming mainstream in the LAN arena. At that time, 50/125, 100/140, and later, 62.5/125 (core and cladding diameter in microns), multimode optical fiber sizes were the short-distance LAN choices. The large diameter core allowed optical launch using LEDs, rather than more costly and finicky lasers.   The 906 SMA optical connector was one of the first popular optical connectors, but it had a few annoyances. For example, a "Delrin sleeve" (hollow plastic cylinder) was required to mechanically align the ferrules of a mated pair, precisely enough that the loss should remain under 3 dB. Being detachable, these Delrin sleeves had a habit of falling on the floor and rolling under anything that prevented someone from ever finding them again.   Compared to today's connectors, with losses of a fraction of a dB, this 3dB loss spec was atrocious. But it was a fact of life, and we had to live with it.   One day, our lab technician was setting up the optical portion of our corporate network and ran into difficulty. He came to me for help because he was getting unexplained bit errors over all the optical links. We had just started manufacturing an Ethernet 10Base-T and FOIRL (Fiber Optic Inter Repeater Link) hub, but he was trying to use Cabletron optical transceivers at the desktop ends. Plus, he had set up an optical patch panel that added an extra mated pair per patch cord.   I had designed the optical cards for our own product. In spite of much complaining from production, I insisted on tweaks to ensure that the green "Link Good" indicator LED would not turn on unless the incoming optical signal level was sufficient to ensure a bit error rate of better than 10 -9 . This was a requirement of the FOIRL Specification.   The Cabletron folks did not want expensive tweaks, so they designed their gear with a "Link Good" indicator LED that turned on with the slightest optical input -- never mind that it was so weak that the bit error rate made the link unusable -- thus, their gear was not FOIRL compliant.   Our lab technician was fooled by the Cabletron desktop transceivers "Link Good" LEDs. I showed him, with my optical power meter, that the link was not good, and that the Cabletron LEDs were lying to him. Then I told him the only solution was to rearrange his patch panel to eliminate one of the two optical couplings -- use cord and splice bushing only, rather than splice bushing to patch cords to another splice bushing. This eliminated 2 dB to 3 dB of loss and the links worked.   Note: 3 dB of optical loss is equivalent to 6 dB of electrical loss.   Glen Chenier Engineer

One of the many astonishing aspects of today's fiber-optic connectors is the mechanical precision that allows low-loss mated pairs, especially considering that single-mode fiber has an optical core of about 9 microns in diameter. Two of these cores, from opposing fibers, must be aligned with almost-perfect mechanical precision to affect the least amount of optical loss.   Positive contact and angled polish keep losses and reflections to a minimum. Of course, this small core size means that the slightest speck of dust on the single-mode core can introduce disastrously high levels of loss, so absolute cleanliness (cleaning the end faces of the connector ferrules) is a must every time a connection is made.     It was not always this good. Quite a few years ago, optical fiber networking was becoming mainstream in the LAN arena. At that time, 50/125, 100/140, and later, 62.5/125 (core and cladding diameter in microns), multimode optical fiber sizes were the short-distance LAN choices. The large diameter core allowed optical launch using LEDs, rather than more costly and finicky lasers.   The 906 SMA optical connector was one of the first popular optical connectors, but it had a few annoyances. For example, a "Delrin sleeve" (hollow plastic cylinder) was required to mechanically align the ferrules of a mated pair, precisely enough that the loss should remain under 3 dB. Being detachable, these Delrin sleeves had a habit of falling on the floor and rolling under anything that prevented someone from ever finding them again.   Compared to today's connectors, with losses of a fraction of a dB, this 3dB loss spec was atrocious. But it was a fact of life, and we had to live with it.   One day, our lab technician was setting up the optical portion of our corporate network and ran into difficulty. He came to me for help because he was getting unexplained bit errors over all the optical links. We had just started manufacturing an Ethernet 10Base-T and FOIRL (Fiber Optic Inter Repeater Link) hub, but he was trying to use Cabletron optical transceivers at the desktop ends. Plus, he had set up an optical patch panel that added an extra mated pair per patch cord.   I had designed the optical cards for our own product. In spite of much complaining from production, I insisted on tweaks to ensure that the green "Link Good" indicator LED would not turn on unless the incoming optical signal level was sufficient to ensure a bit error rate of better than 10 -9 . This was a requirement of the FOIRL Specification.   The Cabletron folks did not want expensive tweaks, so they designed their gear with a "Link Good" indicator LED that turned on with the slightest optical input -- never mind that it was so weak that the bit error rate made the link unusable -- thus, their gear was not FOIRL compliant.   Our lab technician was fooled by the Cabletron desktop transceivers "Link Good" LEDs. I showed him, with my optical power meter, that the link was not good, and that the Cabletron LEDs were lying to him. Then I told him the only solution was to rearrange his patch panel to eliminate one of the two optical couplings -- use cord and splice bushing only, rather than splice bushing to patch cords to another splice bushing. This eliminated 2 dB to 3 dB of loss and the links worked.   Note: 3 dB of optical loss is equivalent to 6 dB of electrical loss.   Glen Chenier Engineer

此视频简单地介绍了一些关于路由器的接口和安装，希望对大家有所帮助！嫌它太初级的兄台们可以直接无视~O(∩_∩)O~ --------------------------   WIZnet 专注全硬件 TCP/IP 协议栈，面向嵌入式开发应用，为物联网的发展助力！ 官方博客： blog.iwiznet.cn   官方网站： www.iwiznet.cn 欢迎联系我们提供宝贵意见！

W5200 Power Down Mode Application Note     W5200 和W7200 都有提供两种很吸引性的功能, 就好像有掉电模式和LAN叫醒功能. 但是这两种功能不可以同一个时间一齐使用. 如果已经启动掉电模式, 芯片中的PHY 会关闭和停止它的功能. 所以如果在掉电模式的情况下, 它是不可以使用LAN叫醒功能,因为这个功能是通过LAN来接收魔术数据包来叫醒的. 一般来说, 掉电模式是一个可以控制PHY 开关的功能来控制使用的电量. LAN叫醒功能是控制MCU 来转换MCU的模式是睡觉模式或正常模式. 当 W5200 接收到魔术数据包, LAN叫醒功能 就会通过W5200打断MCU的程序给MCU进入睡觉模式.       1. 连接图 2. W5200E01-M3_PWDN的示例代码 if (strcmp(choice,”7″)== 0) { bTreat = (bool)SET; if((IINCHIP_READ(PHY)0×08) == 0×00){ SerialPutString(“\r\nEnabling…\r\n”); GPIO_SetBits(GPIOB, WIZ_PWDN); Delay_ms(500); if((IINCHIP_READ(PHY)0×08) == 0×08) SerialPutString(“\r\nEnabled PHY Power Down!!!\r\n”); } else{ SerialPutString(“\r\nAlready Enabled!!!\r\n”); } }   当你已经选择7号这个功能, 如果代表PHY 的寄存器是没有启动掉电模式(0×00), GPIO会启动为掉电模式. 如果已经启动,串口就会打印出掉电模式已经启动.   if (strcmp(choice,”8″)== 0) { bTreat = (bool)SET; if((IINCHIP_READ(PHY)0×08) == 0×08){ SerialPutString(“\r\nDisabling…\r\n”); GPIO_ResetBits(GPIOB, WIZ_PWDN); Delay_ms(3000); if((IINCHIP_READ(PHY)0×08) == 0×00) SerialPutString(“\r\nDisabled PHY Power Down!!!\r\n”); } else{ SerialPutString(“\r\nAlready Disabled!!!\r\n”); } } 当你已经选择8号这个功能, 如果代表PHY 的寄存器是启动掉电模式(0×00), GPIO会关闭掉电模式. 如果已经关闭,串口就会打印出掉电模式已经关闭.   3. 配置 IAR Embedded Workbench Type.h   如果你使用的是W5200E01-M3, W7200的定义就要关闭. #define __DEF_W5200__ //#define __DEF_W7200__ 如果你使用的是iMCU7200EVB, W5200的定义就要关闭. //#define __DEF_W5200__ #define __DEF_W7200__ Flash Loader Demonstrator 启动”Flash Loader Demo software”编程程序到 iMCU7200EVB或 W5200E01-M3. 如下是编程步骤:   PC1 是需要使用静态IP 在串口终端程序 在 W5200E01-M3_PWDN 的程序中, PHY的掉电模式已经默认为关闭. PHY 的掉电的意思是代表控制PHY. 所以, 掉电模式是启动代表不可以传送和接收任何数据包.   4. 设置网络设置 5. 启用PHY掉电 6. 禁用PHY掉电 7. Ping测试 PC 1 ping 到 iMCU7200EVB(192.168.11.254). 如果 PC1 使用串口终端程序去改变 W7200 到功能8. 关闭PHY 的掉电模式之后再开到 启用PHY掉电模式, PC 1 就不可以ping 到 iMCU7200EVB 和 会打印出信息 “Request timed out”. 如果 PC1 使用串口终端程序改W5200到功能7来启用PHY掉电模式之后改到关闭PHY 的掉电模式, PC 1 就可以Ping iMCU7200EVB .     Written By: Ron, HK member W5200 Power Down Mode Application Note