Silicon Chip – July 2019

siliconchip.com.au Australia’s electronics magazine July 2019 21

tween 100 and 10,000 times less than
the emissions from the sole of a typi-
cal shoe.

4. Voting error in Belgium: In 2003
   in Schaerbeek, Belgium, there was
   electronic voting for an election, and
   a single candidate obtained an extra
   4096 votes. The apparent error was
   only noticed because that was more
   votes than was possible.
   The error was blamed on a Single
   Event Upset (SEU) due to radiation,
   causing a bit flip (inversion of zero
   to one).
   To explain how this can happen,
   recall that binary code is represented
   as bits (zero or one) in positions for
   1, 2, 4, 8 etc.
   Position 13 of a binary number rep-
   resents a value of 4096. So if that bit
   flips from zero to one, for example,
   the binary number 0000000000000
   (zero) will become 1000000000000
   (decimal 4096).


5. Qantas QF72: On 7th October
   2008, Qantas flight QF72 experienced
   two sudden, uncommanded pitch-
   down maneuvers at 37,000 feet alti-
   tude (11300m) which caused injuries

to passengers, crew and damage to

the aircraft. Investigators traced the

problem to one of three air data iner-

tial reference units, which sent incor-

rect data to the flight control systems.

The following causes were consid-

ered for the “upset” (as it is officially

described): software corruption, soft-

ware bug, hardware fault, physical en-

vironment, EMI from aircraft systems,

EMI from other onboard sources, EMI

from external sources and SEE (Single

Event Effect).

All were rated “unlikely” or “very

unlikely” to have occurred, except for

SEE due to radiation, which was rated

as “insufficient evidence to estimate

likelihood”.

You can read the comprehensive

and fascinating report about the up-

set at: siliconchip.com.au/link/aaq6

6. Voyager 2 bit flip: On 22nd
   April 2010, the spacecraft Voy-
   ager 2 (see SILICON CHIP, Decem-
   ber 2018; siliconchip.com.au/
   Article/11329) had a problem with
   the format of the scientific data being
   returned to Earth.
   On May 12th, engineers retrieved

a full memory dump from the Flight

Data System computer, which for-

mats the data to be returned to Earth.

They found a single bit of memory

had flipped to the opposite of what it

was meant to be.

They reproduced this in a computer

on the ground and determined it gave

the same data format problems as were

being seen from the spacecraft.

On May 19th, commands were sent

to the spacecraft to reset the affected

memory bit and on May 20th, engi-

neering data received from the space-

craft was normal again.

“Demonstration of the effects of ra-

diation on a commercial video camera”

siliconchip.com.au/link/aaq7

“Watch A GoPro Travel Through Ex-

treme Radiation” siliconchip.com.au/

link/aaq8

“Declassified U.S. Nuclear Test Film

#62” – from 1962, about the effects

of high altitude nuclear detonations:

siliconchip.com.au/link/aaq9

Interesting Videos...

Designers of space applications need to reduce design cycles

and costs while scaling development across missions with dif-

ferent radiation requirements. To support this trend, Microchip

Technology Inc.has introduced the space industry’s first Arm-

based microcontrollers (MCUs) that combine the low-cost and

large ecosystem benefits of Commercial Off-the-Shelf (COTS)

technology with space-qualified versions that have scalable

levels of radiation performance.

Based on the automotive-qualified SAMV71, the SAM-

V71Q21RT radiation-tolerant and SAMRH71 radiation-hardened

MCUs implement the widely deployed Arm Cortex-M7 System

on Chip (SoC), enabling more integration, cost reduction and

higher performance in space systems.

The SAMV71Q21RT and SAMRH71 allow software devel-

opers to begin implementation with the SAMV71 COTS device

before moving to a space-grade component, significantly re-

ducing development time and cost. Both devices can use the

SAMV71’s full software development toolchain, as they share

the same ecosystem including software libraries, Board Sup-

port Package (BSP) and Operating System (OS) first level of

porting. Once preliminary developments are complete on

the COTS device, all software development can be easily

swapped out to a radiation-tolerant or radiation hardened

version in a high-reliability plastic package or space-grade

ceramic package.

The SAMV71Q21RT radiation-tolerant MCU reuses the

full COTS mask set and offers pinout compatibility, making

the transition from COTS to qualified space parts immediate.

While the SAMV71Q21RT’s radiation performance is

ideal for NewSpace applications such as Low Earth Orbit

(LEO) satellite constellations and robotics, the SAMRH71

offers the radiation performance suited for more critical

sub-systems like gyroscopes and star tracker equipment.

The SAMV71Q21RT radiation-tolerant device ensures

an accumulated TID of 30Krad (Si) with latch up immuni-

ty and is nondestructive against heavy ions. Both devices

are fully immune to Single-Event Latchup (SEL) up to 62

MeV.cm²/mg.

The SAMRH71 radiation-hardened MCU is designed spe-

cifically for deep space applications.

Radiation-Hardened

Atmel Range from

As this issue was going to press, the

following media release came across

our desks. We’re not sure how many

readers would be into space and

satellite applications but we

thought it interesting nevertheless!