Logic Design for Array-Based Circuitsby Donnamaie E. WhiteCopyright © 1996, 2001, 2002 Donnamaie E. White |
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IntroductionLast Edit July 22, 2001 SelectionThe choice between full-custom, semi-custom, fixed or simple gate-level custom is based on several factors. These include: architectural requirements, interface technology requirements, size restrictions, speed (maximum worst-case operating frequency), power limitations, power supply options, manufacturing cycle time, cost, packaging options, and design time. Figure 1-3 characterizes the problem. Basis for DiscussionThe discussion in this text will refer primarily to Applied Micro Circuits Corporation arrays for examples of current technology. These include: Bipolar arrays: the Q5000, and the Q20000 Series; and BiCMOS arrays: the Q14000 and Q24000 Series. However, the design methodology; can be applied to any arrays from any vendor for any array technology and to any future arrays developed by AMCC and the other array vendors.
WHERE DO YOU START?Figure 1-3 The Selection Problem ![]() Note:Later chapters in this text refer to engineering workstations (EWS) and the methodology for their use in the design process. Workstations that are specifically referred to are: the Mentor Graphics System on Apollo and the Valid on SUN. Simulators referenced include Verilog on SUN4 and Lasar 6 on the VAX under VMS. The basic tools required for a design remain the same regardless of the workstation, platform, framework or mainframe used. Circuit ArchitectureA fixed-instruction set microprocessor or sequencer has a predefined architecture and instruction set. A bit-slice solution places some constraints on the designer in terms of architecture but leaves most of the definition to the user by way of the selected interconnections between bit-slice modules and the microprogram control. An SSI/MSI implementation allows the designer the specify in complete, exact detail the architecture desired. The SSI/MSI design can be implemented in full custom or semi-custom VLSI. Bit-slice modules can be emulated on arrays. The ASIC arrays are big enough to support a complex ALU module but not yet large enough for one array to replace a full microprocessor.
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Copyright @ 2001,
2002 Donnamaie E. White, White
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