3.5 Static RAM – Components 4.2, 4.3, and 5

Purpose of the test: Detect stuck bits and coupling faults in SRAM and on the data bus, as well as any addressing problems.

The internal SRAM is used for volatile storage of data and any faults related to this can be catastrophic for the appliance control.

Acceptable measures for Fault detection include periodic testing and/or data redundancy, e.g. parity bits. The latter is cumbersome without hardware implementation specific for this purpose, leaving periodic testing with, e.g. March algorithms as the best choice.

If the entire SRAM cannot be tested in one go, the tested memory sections must have some overlap to allow for detection of coupling faults.