Enabling Gigabit IP for Embedded Systems

Author: Nicholas Tsakiris

Tsakiris, Nicholas, 2009 Enabling Gigabit IP for Embedded Systems, Flinders University, School of Computer Science, Engineering and Mathematics

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Abstract

For any practical implementation of chip design, there needs to be a hardware platform available for the purpose of prototyping and implementation of FPGA-based programs, whether they are written in VHDL or Verilog. Communication between the platform and a computer is a useful feature of many hardware solutions as it allows for the capability of regular data transmission between the two devices. Furthermore, the ability to communicate between the platform and a computer at high-speeds requires a specially constructed interface, one that can be modified by the designer at their choosing. There are a number of commercial packages which provide a hardware platform to perform this task, however there are drawbacks to many of the available options. Some may require special hardware to connect to a computer using proprietary connectors or boards, which increases the cost and reduces the flexibility of any solution. Other options may have limited access to the internal structure of the interface, limiting the ability of the developer to modify the interface to suit their needs. There may be an extra cost to provide the code to the interface, separate from the board, which can also tax design budgets. This dissertation provides a solution in the form of a Gigabit Ethernet connection with a custom IP/network layer written in VHDL to facilitate the connection. With an increasing number of IP-enabled devices available such as IPTV and set top boxes, the ability to link hardware using Ethernet is very useful and so the development of a lean and capable network layer was considered a suitable focus for the project. The overall goal has been to provide an interface which is cheap, open, robust and efficient, retaining the flexibility a developer might require to modify the code to their needs. After covering some basic background information about the project, the dissertation looks at the requirements of the board and interface, as well as the alternative interface solutions which were looked at before deciding on Gigabit Ethernet. The protocols used in Ethernet are then covered, with both an explanation of the structure of each and their relevance to the implementation. The Finite State Machines which control operation of the interface are covered in depth, with an explanation of their inter-connectivity to each other and how they fit in the data-flow between the computer and the board. Error correction and reliability is discussed, as well as any remaining components critical to the operation of the interface. Pipelining, the method of design which provides the speed required for Gigabit Ethernet, is covered along with the extra speed optimisation techniques used in the design such as RAM swinging buffers. Testing and synthesis are covered which ensure the design is as robust as possible, both in simulations and in real-world applications. The final design was implemented on a Xilinx Spartan 3 FPGA (XC3S5000-5FG900C) and capable of a maximum speed of 128.287 MHz, which is more than enough to satisfy the requirements of Gigabit Ethernet under a variety of network conditions. The interface code occupies 1,166 slices of logic on the FPGA (3% of the total amount of logic available), making it sufficiently compact to run large projects on the same chip. The core was tested on physical hardware and performed correctly at real line Gigabit speeds. Configuration of the computer along with the method of connecting to the board and transferring data is mentioned, with explanation of the code run on the computer to make this possible. Finally, the dissertation provides an example application through the use of JPEG2000 image compression/decompression.

Keywords: VHDL,FPGA,embedded,gigabit,ethernet,network,TCP,IP,UDP,ICMP
Subject: Computer Science thesis

Thesis type: Masters
Completed: 2009
School: School of Computer Science, Engineering and Mathematics
Supervisor: Professor Greg Knowles