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Extension of Asynchronous Design Automation Tools. Michael Boyer Advisor: Cherrice Traver Steinmetz Symposium 2005. Introduction. Synchronous (clocked) Clock skew Asynchronous (self-timed). Advantages of Asynchronous. No clock skew problem Increased power efficiency
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Extension of Asynchronous Design Automation Tools Michael Boyer Advisor: Cherrice Traver Steinmetz Symposium 2005
Introduction • Synchronous (clocked) • Clock skew • Asynchronous (self-timed)
Advantages of Asynchronous • No clock skew problem • Increased power efficiency • Increased performance • Greater tolerance of variation in operating conditions • Greater frequency distribution of electromagnetic noise • Component modularity
Real-World Examples • Amulet 1, 2e, 3, 3i • Oticon DigiFocus hearing aid • Philips 80C51 microcontroller • Intel RAPPID Project
E E O E O O Phased Logic (PL) • Automated translation • Two phase LEDR signaling E
Liveness and Safety • PL synthesis algorithm • Guarantees liveness and safety • Token abstraction
Coarse-Grained PL • Wrap logic blocks with PL circuitry • Logic blocks: • Barrier blocks • Through blocks • Speed-up techniques: • Time borrowing • Early evaluation
VHDL Modeling • New models: • Wrapper models • Environment models • Assumptions • Testing
ATACS • Automatic Timed Asynchronous Circuit Synthesis (ATACS) • Automated verification: • Hazard checking
100-200 ps Verification Example
Results Wrapper for Through Blocks with Time Borrowing: min(D1, D2, D3, D4) + min(D5) ≥ max(C1) + max(xorG) + max(D-latch) – min(C2) – min(xorC) – min(DFF) min(D1, D2, D3, D4) + min(D5) ≥ max(compute) + max(D-latch) – min(C2) – min(xorC) – min(DFF) Wrapper for Through Blocks without Time Borrowing: min(D1, D2, D3, D4) ≥ max(compute) + max(D-latch) – min(nC2) – min(DFF) – min(nC1) Wrapper for Barrier Blocks without Early Evaluation: min(D1, D2, D3, D4) ≥ max(compute) + max(Data DFF setup time) – min(nC)
Future Work • Include results in mapping tool • Use mapping tool to compare PL to synchronous • Implement PL in hardware
Acknowledgements • Cherrice Traver, Union College • Chris Myers, University of Utah • Bob Reese, Mississippi State University • IBM/SRC