Asynchronous Logic Automata Analog Logic Automata David Dalrymple

Logic CA AND OR XOR NAND Each processor a bit, each bit a processor.

Asynchronous Logic • Clocking keeps data in sync – Sometimes we care exactly when

Asynchronous Logic • Traditional architectures have very complex data dependencies • Most asynchronous logic

Consequences of ALA • Power savings from • Active elements – Clocking everywhere –

Analog Logic Automata (Work of Kailiang Chen)

Soft Computation using Analog Logic Digital domain Analog domain – each binary variable –

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Asynchronous Logic Automata Analog Logic Automata David Dalrymple April 17, 2008

Asynchronous Logic Automata

Supercomputer

Supercomputer Code

Architecture

Cellular Microcode Each cell a bit

Logic CA AND OR XOR NAND Each processor a bit, each bit a processor.

Architecture is software.

Logic CA is synchronous T=0 T=1 T=2 T=3

Asynchronous Logic • Clocking keeps data in sync – Sometimes we care exactly when data is ready • Clocking everything wastes energy, time – Sometimes we don't care • Don't need clocks to synchronize – Asynchronous is just clever synchronization • Look at data dependencies

Asynchronous Logic • Traditional architectures have very complex data dependencies • Most asynchronous logic design has lived with these • “Globally asynchronous, locally synchronous”

Data dependencies local

Allow Inaction (0, 1, X)

Charge conservation

Consequences of ALA • Power savings from • Active elements – Clocking everywhere – Charge conservation • Flexible interconnect • Fan-out, fan-in free • No impedance issues • Propagate at gate delay – cm/10 ns

ALA Simulator

Analog Logic Automata (Work of Kailiang Chen)

Soft Computation using Analog Logic Digital domain Analog domain – each binary variable – random variable {0/1} Px (X=0) & Px (X=1)

Example 2 -- Xor

3 x 3 Array Layout