Hardware configuration

• 7x iMX6 Tiny Rex Quad Module

  • 1GHz i.MX6 Quad 1GHz CPU – automotive temperature range (-40°C ~ 125°C)

  • 4x 4Gb DDR3 Memory chips – industrial temperature range (-40°C ~ +95°C)

  • 1GBps Ethernet PHY Tranciever KSZ9031RN – automotive temperature range (-40°C ~ +85°C)

• 3x i.MX6 Tiny Rex Solo Module

  • 1GHz iMX6 Solo 800MHz CPU – industrial temperature range (-40°C ~ +105°C)

  • 2x 4Gb DDR3 Memory chips – industrial temperature range (-40°C ~ +95°C)

  • 1GBps Ethernet PHY Tranciever KSZ9031RN – automotive temperature range (-40°C ~ +85°C)

The modules were plugged into the standard iMX6 Tiny Rex Baseboard Lite. We used a medium-sized heatsink.

Test description

Three of the QUAD boards were running full peripheral test to check functionality of all the peripherals in different temperature range. Rest of the boards where running CPU and Memory test to check reliability and stability of the memory settings and memory layout (this includes three SOLO boards where two of the four memory chips were not fitted).

Here are our configurations & software description:

• 3x iMX6 Tiny Rex Quad peripheral stress testing

  • 1 thread of extensive Memory stress test

  • 1 thread of CPU stress test

  • SATA stress test

  • video playing on the X-server via HDMI output

  • copying a file from the first USB stick to SD card and vice versa

  • copying a file from the second USB stick to SATA hard drive and vice versa

  • pinging the host PC via Ethernet

  • all the messages were printed out on the serial console through connected FTDI cable

  • booting from a SATA hard drive

• 4x iMX6 Tiny Rex Quad Memory stress testing

  • 4 threads of extensive Memory stress test

  • 4 threads of CPU stress test

  • booting from SD card

• 3x iMX6 Tiny Rex Solo Memory stress testing

  • 1 thread of extensive Memory stress test

  • 1 thread of CPU stress test

  • booting from SD card

Notes: USB sticks and SATA hard drives were place outside of the environmental chamber. All the scripts running during the test and the board setup instructions can be found at the bottom of this page in Appendix : How to prepare the test.

The Results

Running the boards at -40°C and -60°C – PASS

Test description: At -40°C we were running the CPU, Memory and peripheral stress tests. Then we lowered the temperature down to -60°C. All the tested boards were working OK during the whole time. Note: Notice, the Linux running on the QUAD boards incorrectly shows CPU temperature below -40°C (it shows 25 instead).

Running the boards at +60°C – PASS

Test description: We increased the ambient temperature (to 60°C, 65°C, 70°C) and we were running the CPU, Memory and peripheral stress tests. We stopped the test when the CPU lowered it’s frequency (it happened when CPU temperature reached 90°C). With our setup, all the boards were running at 60°C. To go higher, we would need to use a bigger heatsink.

Temperature stress test – multiple quick temperature change from -60°C to -10°C and back – PASS

Test description: The ambient temperature went from -60°C to -10°C and back to -60°C. The boards were running the CPU, Memory and peripheral stress tests. All the boards were working perfectly.

Picture: Zoom on the temperature chamber displaying the minimum and maximum temperature (First number shows relative humidity, second one the actual temperature and the last one the dew point).

Appendix

PC Setup

During the test we used DHCP and FTP servers on our control PC. The PC was also used during ethernet ping test and to control all the boards through SSH sessions + serial console. The control PC was using Windows 7 operating system.

1. Network setup – PC

Disable the firewall (PC will not be connected to the internet) and setup static IP address: Press Windows button -> go to Control Panel -> Network and Internet -> Network and Sharing Center -> Change adapter settings (on the right side in the bar) -> double click on Local Area Connection -> Properties -> In tab Networking go to Internet Protocol Version 4 (TCP/IPv4) -> type the static IP address and subnet mask as shown below:

The iMX6 Tiny Rex boards and Control PC are connected to a Gigabit Ethernet Switch. Connect the PC to the switch and turn the switch on. To be able to download the files from FTP server we need to enable the sharing option first. This can be done by setting up the network as a “work network”. You can change it in Control Panel -> Network and Internet -> Network and Sharing Center -> Click to Choose homegroup and sharing options

2. Setting up the TFP and DHCP servers

As TFTP and DHCP server we used Tftpd32 software. For more details about DHCP configuration, see the screenshots below:

3. SSH and Serial console

To control the iMX6 Tiny Rex boards, open TeraTerm serial console and run SSH client to read temperatures. Open one Teraterm and one SSH per board. For the boards with peripheral test, open an extra SSH client to see if any errors occurred.

4. Setup CRON

To be able to check the CPU temperature every minute, we setup a cron job. Before we do so, we need to install postfix package (for Ubuntu file systems):

# sudo apt-get install postfix

To setup a cron tab we will open the file containing all cron jobs. If you run the crontab for the first time you may need to select the text editor.

# sudo crontab -e

Paste following line to the end of this file:

* * * * * { echo -n $(date +\%Y/\%m/\%d-\%T); echo -n "("; echo -n $(date +\%Z); echo -n ") "; cat /sys/devices/virtual/thermal/thermal_zone0/temp; } >> /home/ubuntu/testing-env-chamber/cpu-temp.log

We will use the same time format as stressapptest. We will get the current CPU temperature and save it into the log file. Note: The char ‘%’ has a special purpose in the cron file. When using it in the date command you need to use backslash before the ‘%’.

5. Prepare boards for testing

After the board boots up we need to setup system time. We also would like to backup the old log files and create empty ones for the next measurement. Here you can find a simple script which will help you:

#!/bin/sh

ln -sf /usr/share/zoneinfo/Europe/Bratislava /etc/localtime

date $1

today=`date +%Y-%m-%d.%H:%M`

cd /home/ubuntu/tiny-rex/env-chamber-testing/

mv env-chamber-testing.log env-chamber-testing.log.$today

mv cpu-temp-measuring.log cpu-temp-measuring.log.$today

touch env-chamber-testing.log

touch cpu-temp-measuring.log

Don’t forget to change permissions to be able to run it:

# chmod 777 tiny-rex-test-setup.sh

Then save it and run it. Use time as a parameter (the sequence of digits in this order: mouth day hour minute year – in the example was used 29-July-2015 10:28).

# ./tiny-rex-test-setup.sh 072910282015

6. Show the CPU temperature in SSH

Open one SSH client per board where we will show CPU temperature. We use tail command to show the last part of the log file, which is filled up through the CRON job we setup in previous steps:

# tail -F cpu-temp-measuring.log

7. Error checking during peripheral test

To immediately see if any error occurred during peripheral test, we open a new SSH client and run the following command:

# tail -f env-chamber-testing.log | grep -i "error"

8. Start the stress test

Peripheral test

Before you run the test be sure everything is plugged in. To find out where the devices are mounted you can use:

# fdisk -l

Now you can run the test. As parameters, use device names in following order: SATA, first USB stick, second USB, SD card. We will also write all the logs into one log file:

# ./tiny-rex-peripheral-test.sh sda1 sdb1 sdc1 mmcblk0p1 | tee env-chamber-testing.log

Here you can find the complete test:

#!/bin/sh

# iMX6 Tiny Rex environmental chamber peripheral test

mountDevice() {

mount /dev/$1 /media/$2

cat /etc/mtab | grep -F "/dev/$1 /media/$2"

if [ "$?" -eq "0" ]; then

echo "$2 mounted"

else

echo "$2 not mounted"; exit 2

fi

}

# mount devices

mountDevice $1 sata

mountDevice $2 usb0

mountDevice $3 usb1

mountDevice $4 mmc0

finish_test_now() {

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) Ctrl+C Detected: End of the test"

$precced=0;

kill -INT $vid_pid $str_pid $log_pid;

sleep 6;

test_status=`cat env-chamber-testing.log | grep -i "error" | grep -v -e "0 errors" -e "no corrected errors"`

if [ -z "$test_status" ]

then

echo "*********\nTEST PASS\n*********"

else

echo "*********\nTEST FAIL\n*********\n"

echo "List of detected errors:"

cat env-chamber-testing.log | grep -i "error" | grep -v -e "0 errors" -e "no corrected errors"

fi

exit;

}

# kill all processes if Ctrl+C is detected

trap finish_test_now 2

# tell the X applications where they should run

export DISPLAY=:0

# run X window - wait for the process

service lightdm start

# stressapptest - one thread CPU, one thread memory, sata testing

stressapptest -f /media/sata/tmp-file1 -s 600000 -M 500 -m 1 -C 1 --printsec 10 &

str_pid=$!

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) Starting stressapptest with PID: " $str_pid

# play a video file in an infinite loop

#echo 0 > /sys/class/graphics/fb2/blank

sudo -u "ubuntu" xfce4-terminal --geometry=90x20+860+10 -x mplayer -vo fbdev2:/dev/fb0 -vf scale -zoom -loop 0 -geometry 1024x768+860+370 /home/ubuntu/Clouds.avi > /dev/null 2>&1 &

vid_pid=$!

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) Starting video file playback with PID: " $vid_pid

# open window with a log file

sudo -u "ubuntu" xfce4-terminal --geometry=80x140+10+10 -x tail -F env-chamber-testing.log > /dev/null 2>&1 &

log_pid=$!

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) Starting printing out the log file with PID: " $log_pid

# top

#sudo -u "ubuntu" xfce4-terminal --geometry=90x50+900+10 -x top &

proceed=1

file1="blackbird.wav"

file2="blackbird2.wav"

cp1_from="/media/mmc0/"

cp1_to="/media/usb0/"

cp2_from="/home/ubuntu/"

cp2_to="/media/usb1/"

#copy files in case they are missing

cp /media/$file1 $cp1_from$file1

cp /media/$file1 $cp1_to$file1

cp /media/$file2 $cp2_from$file2

cp /media/$file2 $cp2_to$file2

while [ $proceed -eq 1 ]

do

ping -q -c1 192.168.0.2 >> env-chamber-testing.log

if [ $? -ne 0 ]

then

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) ERROR: Ping failed"

fi

cp1_done=`ps cax | grep $cp1_pid | grep cp`

if [ -z "$cp1_done" ]; then # copy finished

if cmp -s $cp1_from$file1 $cp1_to$file1; then

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) PASS: Copying file from $cp1_from to $cp1_to successful"

else

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) ERROR: Difference between files on $cp1_from and $cp1_to detected"

fi

cp1_temp=$cp1_from # swap destinations

cp1_from=$cp1_to

cp1_to=$cp1_temp

rm $cp1_to$file1 # remove destination file

cp $cp1_from$file1 $cp1_to$file1 &

cp1_pid=$!

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) Started copying file from $cp1_from to $cp1_to"

fi

cp2_done=`ps cax | grep $cp2_pid | grep cp`

if [ -z "$cp2_done" ]; then # copy finished

if cmp -s $cp2_from$file2 $cp2_to$file2; then

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) PASS: Copying file from $cp2_from to $cp2_to successful"

else

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) ERROR: Difference between files on $cp2_from and $cp2_to detected"

fi

cp2_temp=$cp2_from # swap destinations

cp2_from=$cp2_to

cp2_to=$cp2_temp

rm $cp2_to$file2 # remove destination file

cp $cp2_from$file2 $cp2_to$file2 &

cp2_pid=$!

echo "$(date +\%Y/\%m/\%d-\%T)($(date +\%Z)) Started copying file from $cp2_from to $cp2_to"

fi

done

Quad Memory testing

For Quad testing run stressapptest with these parameters:

#stressapptest -s 600000 -M 1000 -m 4 -C 4 -W -l /home/ubuntu/testing-network/stressapptest.log

Solo Memory testing

You can use stressapptest with these parameters:

#stressapptest -s 600000 -M 768 -m 1 -C 1 -W -l /home/ubuntu/testing-network/stressapptest.log