![]() ![]() There is some arithmetic IP of design ware from synopsys, which can’t be implemented in FPGA directly with no performance reduced. ![]() Also it could be implemented by FPGA structure, which cost more area. In FPGA design, vendor support some pre-define special arithmetic block, but it is limited. Specialization arithmetic IP in ASIC design has advanced structure used gate-level or transits-level model optimized. There should take balance strategy in speed and area. So the HDL architecture substitution is necessary. When adapting ASIC code for FPGA, it important to replace all gate-level memory functions with Core Generated ones, in this way, an efficient implementation of memory in FPGA is assured.Īnother important issue when adapting ASIC for FPGA, the asynchronous memory can’t be implemented in FPGA when Core Generator involved. This is quit different with ASIC for which RAM is synthesized from generic NAND. VirtexII FPGA can provided Block RAM, it also supports distributed RAM, which means the four-input LUTs can be used to implement a variety of memory type, including synchronous RAM, ROM, Dual ports, and FIFOs. While in ASIC implement, on chip memory is based on fabrication vendor’s standard memory cell, standard library, which is more flexible. Block-memory on chip should be instantiated as FSM, FIFO, LUT etc. In FPGA implement, memory should be replaced by pre-define internal memory. Replace them with Xilinx instantiated HDL components. When adapting a design to a Xilinx FPGA series, be sure to remove any ASIC-specific code associated with global reset, set and three-state operation. GSR(Global Set/Reset) feature and GTS(Global Three-State) control are dedicated net to Xilinx FPGA series. Sometimes it should be replicated same net in design for big driver capability. For globe driver signal, clock, reset, big fan-out nets should assign to use internal big fan-out buffer. Pre-define internal logic cell have limited fan-out capability of FPGA associated with FPGA vendor’s process. Adding pipeline registers if timing is hard to meet. Another disadvantage, while in high switch speed, the latch became pure combination logic, causing timing confusion. At low switching speed, there will import a new clock in one clock domain. Unlike ASIC, internal latch of FPGA will cause some confusion. It can be used the gating signal as enable signal (CE) of flip-flop by two input MUX, one is Q feedback, the other is data signal. In XXX project there take 3 sub-system partitions, so does FPGA.īecause clock single in FPGA is too sensitive to be affected production some signal jitter, skew, glitch and noise, it should be avoided to use gated control clock. In order to keep similar with ASIC structure, FPGA should take the same partition strategy as ASIC. It's part of my thesis: descript ASIC to FPGA code comvert items. Standard ICs such as NAND, NOR, NOT gates etc found in 74-series. Programmable ASICs such as FPGAs, CPLDs, SPLDs etc.Ĥ. Semi-Custom ASIC such as Cell-based, Standard Cells, Channel/Channel-Less SOGs or MPGAs.ģ. Full Custom ASIC such as Analog ICs, for example ADCs, Mixer, Amplifier.Ģ. My knowledge is based on what I know and what I read, especially from some popular textbooks written by (1) Michael Sebestian Smith, (2) Weste & Eshraghian, and (3) Jan Rabaey.ĪSIC is a general terminology to classify ICs built for application-specific, for a chip that only performs Turbo-Coding, Radix-4 FFT or etc.įPGA is a type of ASIC but more oftenly called programmable ASIC that also grouped PLDs such as SPLDs and CPLDs.ĪSIC, to be strictly called, is actually classified into several domains.ġ. There was a period of time, when I was student, my lecturer told me that he got confused too because during the 60s to 90s, too many jargons in digital ICs emerged during the ASIC boom. I guess many people are misunderstood, not just you. ![]()
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