FPGA Architectures,CPLD's

[harry_madaan]

1)can anybdy tell me abt the differnt architectures of FPGA's?

2) Wats the exact differnce b/w CPLD's and FPGA's in terms of their architecture, their usage, and others trade-offs.

links and pdf files will b hlpful

thnxs
harry

 

[s2c97]

1) the best way to get the different FPGA architecture is to refer to the chip manufacturer's website and get the chip datasheet. You can go to Xilinx, Altera,... websites and you will get all the info you are looking for on the different FPGA architectures.

2)

you can make a search in this forum or just google it.

 

[steven_arnold_85]

CPLDs - Complex Programmable Logic Devices
FPGAs - Field Programmable Gate Arrays

XILINX XC4000 FPGA Structure:

• An array of programmable
blocks of logic called
configurable logic blocks
(CLBs)
• Input to and output from the
array is handled by
input/output blocks (IOBs)
along the edges of the array
• Interconnection of CLBs and
IOBs are made by different
length wire segments and
programmable switch
matrices (PSMs)

• FPGA segmented interconnection structure consists of matrix of metal
segments joined by switch matrices. The number of segments and
switch matrices required to interconnect signals is neither constant nor
predictable giving rise to variable and unpredictable delays

However, as the person above said, it is best to consult manufacturers web pages for exact specs.

As for CPLD's give me a little bit of time to post reply

 

[steven_arnold_85]

•Complex PLDs (CPLDs) consist
of multiple PAL-like blocks on a
single chip

•FPGAs have a much larger number of individual logic blocks than CPLDs, and a
large distributed interconnection structure
–each logic block is much simpler than a PLD

CPLD: small number of large, complex logic blocks
FPGA: large number of small, simple logic blocks

•“Field programmable” means that the devices are configured by a designer
rather than the device manufacturer
•Simplest type of logic block is a lookup table (LUT)
–implemented here using multiplexers and one-bit storage cells (0/1)
•Inputs x1 and x2 drive select inputs on multiplexers
•Any 2-input logic function can be built by programming LUT with appropriate bits
•Easily extended to 3-inputs, 4-inputs, …



Hope this helps