Fault Mitigation in Reconfigurable NoC Routers with Thin Design Rules

2.1. Causes of Faults and Failures

Main types of errors are (ITRS,2013; Reyneri et al., 2010; Pignol, 2010):

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  Transient faults (soft errors);

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  Permanent faults (hard errors).

The existing functionality of a SoC could be restored after a soft error. The hard error occurs as a result of an irreparable damage.

Soft errors are (ITRS, 2013; Reyneri et al., 2010; Pignol, 2010):

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  Single event upset (SEU) – change of a value stored in a flip-flop (SRAM cell) to an opposite value;

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  Multiple cell upset (MCU) – change of values in several neighboring memory cells;

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  Single event transient (SET) – occurrence of a glitch at a transistor output;

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  Single event functional interrupt (SEFI) – a soft error in a component that has an impact on functionality of a whole system; for example, an error that occurred in the processor program counter.

Hard errors are (ITRS, 2013; Reyneri et al., 2010; Pignol, 2010):

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  Stuck at fault (‘0’, ‘1’) – when value in one point of a circuit has the constant value “0” or “1”. It happens due to a physical destruction of a floorplan such as the gap lane;

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  Single event latch-up (SEL) – dramatic increase of the leakage current;