Tips to Choose the Right FPGA

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Field Programmable Gate Arrays (FPGAs) have found their implementation in various platforms. Its first success was established when Application Specific ICs (ASICs) like programmable general purpose processors and digital receivers were replaced with FPGA. As technology has progressed, every generation has got better FPGA devices that have improved density, faster speeds, and larger memory resources. It is a challenge for the embedded system board vendors because every customer has a different requirement while selecting the FPGA component. So, here are some of the best features that will help to choose the right FPGA for your needs:


Virtex-4 Family

The first step towards selecting the right FPGA is understanding the resources that are available. The Xilinx Virtex-4 family is an amazingly advanced system with Xilinx splitting the Virtex-4 into seventeen different products that are categorized into three device groups. This is quite outstanding because the Virtex-II Pro family was not capable of such a diverse categorization.

The working of the Virtex-4 family is pretty simple. The logic resources have a Boolean logic block, multiplexers, adder/subtractor, and a look-up-table that are all arranged in slices. One of the surprising elements of this family is that it allows access to the user to its combinatorial logic, sequential circuits, controllers, and state machines.

In addition to all these features, the distributed memory of the Virtex-4 family is often used for FIFOs, shift registers, and a lot of other functions where the memory plays a vital role. This family also comes with dual port RAMs, deep caches, and large circular delay memory buffers.


Active Termination

If you are looking to choose the right FPGA, you must pay special attention to active termination. The connections should provide a wide range of external hardware that can be connected to multiple devices. The XCITE active termination feature is the latest addition to the to the Virtex-4 family. One of the reasons why this feature has attracted the attention of the users is that it offers both termination of the program within the FPGA and also adjusts the termination impedance so that it can track the various changes in the drive levels that may have been caused due to device variations and temperature changes.

The active termination also acts allows the source-synchronous interfaces to include the serializer and the deserializer blocks that help to match the faster data rates that go up to as much as 1 GHz. The interfaces that are linked to the fast external memory devices such as QDR and DDR have been made easier so that you can hold time requirements and also match different complex setups.


Xtreme DSP

Probably, one of the striking features that will help to choose the appropriate FPGA is the slice of Xtreme DSP. The predecessor of the Virtex-4 family did not have a structure that could support powerful signal processing. However, with the introduction of Xtreme DSP, that part has been settled. It comes with a tight and dedicated logic that can operate 24 x 7 at a speed of up to 500 MHz. This is a dream come true for many users because they have literally demanded better signal processing structures right from the time when Virtex-II Pro family was introduced. A unique thing about the Xtreme DSP feature is that it has a 48-bit path that supports fixed-point hardware and fast transfer to all the rival floating point engines with the help of a 36-bit multiplier output.

Another reason why most of the users will be benefited with this version of DSP is that it has 40 arithmetic and logical modes that are dynamically controlled. Strangely enough, they now support the change in modes during the time without having to recompile the same FPGA. This feature was not present in any of the previous versions and it is expected that the users will be able to choose the right FPGA after considering these points.


Allocating Resources

Resource allocation has always been a significant challenge every time there has been a new FPGA model in the radar. However, the Virtex-4 has completely changed that view because you can now allocate the above-mentioned resources in three different groups. The first group will have an on-board IBM 405 PowerPC processor. This is one of the most powerful processors around and you can easily use them as local microcontrollers. It will help you eliminate the requirement of an extra CPU in order to access supervisory functions at the highest level.

In the second resource, you can allocate sets of serial gigabit transceivers. These can be supported by the age-old serializer/deserializer logic that makes it easier to handle bit rates ranging to 10 GHz. The best thing about allocating the system into different resources is that you can configure different interfaces with the help of IP cores. The ideal FPGA will support switched serial fabrics and high-speed serial standards that include a host of items like SATA, FibreChannel, SONET, Serial RapidIO, and many others.

Lastly, you get an option to allocate the 802.3 compliant Ethernet with media access controllers. That is a cool feature that everyone was waiting for and it will help to make you choose the right FPGA so easily. They have the ability to support tons of Base-x transmit/receive interfaces that are connected to the main system peripherals. These will be ultimately embedded to the PowerPC processors so that you can build a communication link and connect it with the outside world.

Choosing the right FPGA has become much simpler than before. You can take a look at the exclusive features of the Xilinx Virtex-4 family before deciding the appropriate FPGA. The impressive features that this family has will definitely excite you to look for diverse functions. Once everything is up and running, you won’t feel any problem with any kind of communication. Honestly, the Xtreme DSP has been the game changer this time around. As an avid user of FPGA, you should pay more attention to the slices of DSP that you get so that the module works to perfection.


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