R2E 1st Combined Workshop & School Days, 2-3 June 2009

"SEU Tolerance in the ELMB", H.Boterenbrood

Key messages
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The ELMB is composed of standard COTS components,
no special rad-tolerant or rad-hard components were used.

A lot of effort and preparation goes into radiation tests
on a hardware module plus its software, such as the ELMB,
which -in fact- is actually a fairly simple module,
and still only part of a larger system.

Changing a component in the design or a change of
technology by the component manufacturer may have
a large impact on the SEU sensitivity of a module design,
so radiation tests should be repeated
(example: change of processor type on the ELMB).

In the SEU tests of the ELMB we found that SEUs occur in SRAM
and device registers. The software has been written
with a number of adaptations to take this into account,
such as a majority voting scheme, register refresh, and others.

In the SEU tests of the ELMB we did not find any SEUs
in EEPROM or FLASH memory. The software has been adapted
to take advantage of this fact by using the EEPROM
as a kind of 'SEU-free' extension to the SRAM
for storing long-lived variables.

The extra precautions taken in writing the ELMB software
have contributed to mitigate the effects of SEUs in the module
and increase the overall tolerance of the ELMB to SEUs.