基于MCU的嵌入式设计预算以太网

　　基于MCU的嵌入式设计预算以太网

　　嵌入式设备的连接是一个必须具备的，因为我们进入一个普遍的物联网（物联网）世界。无线连接似乎是主要的趋势，但大多数无线设备最终需要找到一个有线互联网连接，增加带宽和可靠性。我们的好朋友，传统的有线以太网连接还是需要的枢纽，聚合、桥、存储和应用服务器的嵌入式节点。低成本的传感器也可以使用有线以太网，而不是无线解决方案时，成本，带宽，方便性或可靠性的问题排除了无线方法。幸运的是，许多低成本单片机的家庭现在提供有线以太网支持传感器，廉价的桥梁和连接聚合可没有“破”预算银行。

　　本文将提供廉价的MCU，支持有线以太网连接类型的概述。一些常见的嵌入式应用程序，将需要有线连接的例子将演示如何关键MCU的功能和功能相匹配的重要应用需求。

　　Ethernet connectivity in the embedded world

　　Ethernet is such a pervasive element in embedded systems we usually do not give it much thought -- it’s just the “ether” over which computers communicate. Since its initial standardization in 1985 Ethernet has grown and evolved from the original 3 Mbit/s data transfer rate to 100 Gbit/s and has spawned a variety of different media and connection topologies. The flexibility of the multi-layer OSI model and the underlying message structure supported the evolution and optimization that has allowed Ethernet to survive and prosper over several decades.

　　Embedded devices use Ethernet connectivity to send and receive data and control information. More advanced embedded systems can use Ethernet to transmit and receive code updates to add new features and to fix bugs or security weaknesses that can be exploited by hackers to steal confidential information. These updates must be protected from security exploits， or hackers can use the update facility to fully compromise the system and use it as an entry point to attack other portions of the network. Even low-cost embedded systems may make use of the convenience of remote updates， so some level of security must be considered even when the design is done “on a budget.”