最近调这部分，我想通过TM4C把以太网数据转换为串口，然后送给FPGA。.不需要什么协议栈lwip，就纯粹倒一下数据，当作一个PHY。看了一下没有头绪啊，求一份参考例程
哈哈，你太幸运了，我之前刚刚拿到一份TI DESIGN的文档。
就是用129设计的以太网转UART的设计。
Serial communications (RS-232/422/485) have traditionally been used in industrial automation to connect
various instruments such as sensors and data loggers to stand alone monitoring stations such as
computers. The limitations of serial communications, such as distance, accessibility, and the amount of
data transferred at any one time and speed, has led to a demand for a more flexible means of
communicating. When a legacy product contains only a serial port for a configuration or control interface,
continuing to access the legacy product through the serial interface can become challenging over time.
Newer computers, especially laptops, do not necessarily have serial ports, and a serial connection is
limited by cable length (typically 10 m). Using Ethernet in place of the serial port provides many benefits.
Although slow to catch up with IT infrastructure in commercial environments, Ethernet is increasingly
regarded as the defacto standard of communications in industrial markets. However, the sheer volume of
existing serial-based products and the low cost and ease of integrating these ‘legacy’ protocols means
that serial communication is strong in many areas of industry. Due to the minimal processing power
required, the ruggedness and reliability of connectors, even relatively new products such as GPS
receivers continue to adopt RS-232 and RS-485.
RS-485 has been the PHY protocol for industrial networks since Modbus was launched by Modicon in the
1970s. Other manufacturers followed Modicon and used protocols such as PROFIBUS DP and
INTERBUS. Contemporary systems are Ethernet-based to allow individual "islands of automation" to
share data captured throughout the plant and the company, "top floor to shop floor", and in some cases,
the world. To enable legacy serial based hardware to take advantage of Ethernet, Serial-to-Ethernet
device converters were designed.
Ethernet is a more common interface available on computing equipment today:
• The legacy product can be shared more easily (instead of changing a cable connection, a new
connection over the existing network is made).
• 10-m cable length is no longer an issue (subject to tolerance of the increased transmission delay if the
two pieces of equipment are separated by several routers or are located on a heavily loaded network
segment).
详细的资料如以下设计文档：
