Emulation system having multiple emulated clock cycles per emulator clock cycle and improved signal routing

• US 5,923,865 A
• Filed: 06/28/1995
• Issued: 07/13/1999
• Est. Priority Date: 06/28/1995
• Status: Expired due to Term

• Current Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Original Assignee: Quickturn Design Systems Incorporated (Cadence Group)
• Inventors: Schaefer, Ingo, Chilton, John, Sarno, Tony
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): McNair, Herbert
• Application Number:
  US08/496,239
• Time in Patent Office: 1,476 Days
• Field of Search: 395/500, 395/578, 395/183, 395/183.1, 364/488-491
• US Class Current: 703/23
• CPC Class Codes: G06F 11/261 by simulating additional hardware, e.g. fault simulation
• CPC Class Codes: G06F 30/331 with hardware acceleration, e.g. by using field programmable gate array [FPGA] or emulation

Abstract

A logic emulation system for emulating the operation of a circuit. A uniform routing architecture is provided where a first set of selectors (multiplexers) is coupled to a set of shift registers that are in turn coupled to a second set of selectors. The outputs of the second set of selectors are coupled to the inputs of the logic processors. The arrangement of first selectors coupled to shift registers coupled to second selectors coupled to logic processors ensures that uniform routing exists among all of the logic processors in the emulation system. This, in turn, provides a flat programming model so that compilation steps including technology mapping and scheduling are independent of each other, resulting in faster compile times.

Claims

1. An emulation system for emulating a circuit design, wherein the emulation system includes a logic processor for solving equations to emulate the circuit design, wherein the logic processor includes logic processor inputs and logic processor outputs, the emulation system comprising:

a first selector having first selector inputs and first selector outputs, wherein one or more outputs from the logic processor are coupled to the first selector inputs wherein the first selector selects a subset of signals at the first selector inputs and applies the selected signals to the first selector outputs;

a register having register inputs and register outputs, wherein the register inputs are coupled to the outputs of the first selectors, wherein the register stores the signals received from the selectors;

a second selector having second selector inputs and second selector outputs, wherein the second selector inputs are coupled to the register outputs for selectively applying the register outputs to the second selector outputs;

wherein the inputs of the logic processor are coupled to the outputs of the second selectors;

wherein the first selector includes 256 48;

1 multiplexers;

wherein the register includes 256 shift registers, each having an input and an output, wherein the outputs from the 48;

1 multiplexers in the first selector are coupled to the shift registers one-to-one, wherein the shift registers each have 64 stages and 64 bits of parallel output lines for a total of 64×

256=16,384 shift register parallel output lines;

wherein the second selector includes 128 1024;

1 multiplexers coupled to the shift register parallel output lines so that groups of 8 1024;

1 selectors receive the same 1024 outputs from a group of 16 shift registers; and

Wherein the logic processor includes 8 processors, wherein each processor includes 16 inputs, wherein the processor inputs are coupled to the outputs of the 128 1024;

1 multiplexers so that the 128 1024;

1 multiplexers are coupled to processors according to an assignment modulo 16.