- Jun 1, 2006
PSA: Beware of cosmic rays
As if rollovers, suicidal deer, and thieves who break in with laptop computers weren't enough to worry about, now there's a new menace on the roadways - high-energy neutrons from cosmic rays.
Let's back up a moment. The increasing complexities and decreased time-to-market demands for automotive electronics has caused some manufacturers to migrate from microcontrollers and ASICs to field-programmable logic arrays (FPGAs). Devices based on volatile SRAM are the most common and also the most economical, but they rely on successfully loading and maintaining the device configuration into RAM upon each power-up.
Corruption of SRAM - where a stray cosmic ray disrupts the electron charge of a memory cell - has been a known phenomenon in the PC world for quite some time, but typically does not put the user at risk of a safety-critical failure. The story isn't the same in an automobile, where SRAM corruption can potentially cause a malfunction, or even the complete shut-down of a powertrain or safety system device. As annoying as PC crashes may be, it figures that a similar event in an ECM, ESP, or airbag module would be far worse.
It's highly unlikely that we'll ever see a recall that advises owners to minimize exposing their vehicles to cosmic radiation, but this issue does provide a sliver of insight into the challenges faced by those who design today's ever-more-complex vehicles.
[Source: Automotive Design Line via EE Times]