Field Programmable Gate Array - What is it? 2D array of logic blocks - PowerPoint PPT Presentation

Field Programmable Gate Array - What is it? ◮ 2D array of logic blocks surrounded by a interconnection matrix and I/O Fundamental Structure Altera Cyclone IV ◮ Programmable, but not in the usual sense ◮ Programmed with a bit file loaded into SRAM ◮ Internal SRAM holds the configuration for logic and interconnect ◮ Schematics are rarely used, HDLs mostly

FPGAs as compared to ASICs - Usage models ◮ ASIC ◮ Application Specific - does one thing - fixed circuit ◮ MPEG Decoder, Dolby Noise Reduction, MRI Image Processor ◮ Very cheap in very large volumes ◮ FPGA ◮ Extremely Flexible - can do many things - infinitely changeable ◮ uC, MPEG Decoder, digital signal processor,... ◮ Relatively expensive in even fairly large volumes

FPGAs as compared to ASICs - Architecture ◮ ASIC ◮ About 200 Predesigned (standard) cells: NOR, NAND, XOR ◮ Each cell chosen and sized by synthesis ◮ Very dense, very optimized design ◮ Full mask set needed, diffusion, contacts, wells,...everything ◮ Requires test circuitry insertion, test vector generation ◮ FPGA ◮ Combo logic via Logic Elements (LE) - SRAM memory lookup ◮ Prefabricated PLL, Embedded Memory, Embedded Multipliers ◮ Prefabricated interconnect fabric, clock trees, and I/O cells ◮ Fully tested at manufacture

FPGAs as compared to ASICs - Time and Cost ◮ ASIC ◮ Full mask set 1M $ (90nm) to 2M $ (40nm) dollars ◮ NRE 50-250K $ ◮ Sign-off to 1st article 2-3 months ◮ Re-spin, 2-3 months total, 100’s of K $ , loss of market window ◮ Expensive tool-set; Takes a minimum of 1M $ to play the game ◮ 1 seat of DC shell is about 150-200K $ ◮ FPGA ◮ Parts are prefabricated, no NRE ◮ Respin in one day or less ◮ Tool-set, couple of K $ at most, many are free ◮ No test insertion or vectors, fully tested at manufacture

FPGA Relative advantages/disadvantages ◮ FPGA Advantages ◮ Time to market (TTM): 1 month ≈ 10% market share ◮ Flexibility: one part reused for many projects ◮ Risk: Bugs are easier to find, simple and fast to fix ◮ Capacity of parts continues to increase quickly ◮ FPGA disadvantages ◮ 40x the area of ASIC ◮ 3-4x the delay of ASIC ◮ 12x the power of ASIC (Kuon and Rose, FPGA 2006)