FONT SIZE : AAA
One of the main contributors towards system flexibility is the physical arrangement of the boards themselves. For example, there are commercial boards on the market which have 20 or more FPGAs mounted on a single board. If you need close to 20 FPGAs for your design, then such a monster board might look attractive. On the other hand, if you need considerably fewer FPGAs for this project but possibly more for the next one, then such a board may not be very efficient. A modular system that allows for expansion or the distribution of the number of FPGAs can yield greater return on investment because it is more likely that the boards will be reused over multiple projects. For example, an eight-FPGA prototype might fit well onto a ten-FPGA board (allowing room for those mid-project enhancements) but using a modular system of two four-FPGA boards would also work assuming extra boards can be added. The latter approach would allow a smaller follow-on project to use each of the four-FPGA boards autonomously and separately whereas attempting to reuse the former ten-FPGA board would be far less efficient.
This exact same approach is pertinent for the IO and peripherals present in the prototype. Just because a design has four USB channels, the board choice should not be limited only to boards that supply that number of channels. A flexible platform will be able to supply any number up to four and beyond. That also includes zero i.e., the base board should probably not include any USB or other specific interfaces but should readily allow these to be added. The reason for this is that loading the base-board with a cornucopia of peripheral functions not only wastes money and board area, most importantly it ties up FPGA pins which are dedicated to those peripherals, whether or not they are used.
In particular, modular add-ons are often the only way to support IP cores because either the RTL is not available or because a sensitive PHY component is required. These could obviously not be provided on a baseboard so either the IP vendor or the board vendor must support this in another way. In the case of Synopsys ® , where boards and IP are supplied by the same vendor, some advantage can be passed on to the end user because the IP is pre-tested and available for a modular board system. In addition, as IP evolves to meet next-generation standards, designers may substitute a new add-on IP daughter card for the new standards without having to throw away the rest of the board.
An important differentiator between FPGA boards, therefore, is the breadth of available add-on peripheral functions and ease of their supply and use. An example of a library of peripheral boards can be seen at the online store of daughter cards supplied by Synopsys to support FPGA baseboards. The online store can be seen at www.synopsys.com/apps/haps/index .
In general, end-users should avoid a one-size-fits-all approach to selecting an FPGA-based prototyping vendor because in the large majority of cases, this will involve design, project and commercial compromise. Customers should expect their vendors to offer a number of sizes and types of board; for example, different numbers of FPGAs, different IO interfaces etc. but it is important that they should be as cross-compatible as possible so that choosing a certain board does not preclude the addition of other resources later. The approach also requires that modules are readily available from the vendor’s inventory, as the advantage of modularity can be lost if it takes too long to obtain the modules with which to build your platform.
A critical issue with such a modular approach is the potential for loss of performance as signals cross between the various components and indeed, whether or not the components may even be linked together with enough signals. We should therefore now look closely at the interconnect issues involved in maintaining flexibility and performance.
Manufacturer:Xilinx
Product Categories: Memory - Configuration Proms for FPGA's
Lifecycle:Obsolete -
RoHS: No RoHS
Manufacturer:Xilinx
Product Categories: Programmable logic array
Lifecycle:Active Active
RoHS: No RoHS
Manufacturer:Xilinx
Product Categories: Programmable logic array
Lifecycle:Active Active
RoHS: No RoHS
Manufacturer:Xilinx
Product Categories: CPLDs
Lifecycle:Active Active
RoHS:
Manufacturer:Xilinx
Product Categories: Embedded - FPGAs (Field Programmable Gate Array)
Lifecycle:Active Active
RoHS:
Support
