27-06-2012, 04:09 PM
FPGA: The chip that flip-flops
fpga.ppt (Size: 1,008.5 KB / Downloads: 164)
What are Programmable Chips?
As compared to hard-wired chips, programmable chips can be customized as per needs of the user by programming
This convenience, coupled with the option of re-programming in case of problems, makes the programmable chips very attractive
Other benefits include instant turnaround, low starting cost and low risk
What are Programmable Chips?
As compared to programmable chips, ASIC (Application Specific Integrated Circuit) has a longer design cycle and costlier ECO (Engineering Change Order)
Still, ASIC has its own market due to the added benefit of faster performance and lower cost if produced in high volume
Programmable chips are good for medium to low volume products. If you need more than 10,000 chips, go for ASIC or hard copy
What is Available?
PLA (Programmable Logic Array) is a simple field programmable chip that has an AND plane followed by an OR plane. It is based on the fact that any logical function can be written in SOP (Sum of Products) form thus any function can be implemented by AND gates generating products which feed to an OR gate that sums them up
Lookup Table
A LUT (Lookup table) is a one bit wide memory array
A 4-input AND gate is replaced by a LUT that has four address inputs and one single bit output with 16 one bit locations
Location 15 would have a logic value ‘1’ stored, all others would be zero
LUT’s can be programmed and reprogrammed to change the logical function implemented
FPGA Design Cycle
Define a new project and enter the design using VHDL or Verilog languages. Design can also be entered using Schematic diagrams that can be translated to any HDL
Compile and simulate the design. Find and fix timing violations. Get power consumption estimates and perform synthesis
Download the design to FPGA using a programmer board