VAR-SOM-MX6 Android Unit Testing M6.0.1 1.0.0 R0

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Unit Testing & Engineering Notes

1 Audio

1.1 Changing Volume

Increasing the audio volume is done via. At the hyper terminal shell, type:

root@android:/ # tinymix

You will get a list of all available mixer option. The volume is controled by:
0 INT 2 PCM Playback Volume 127 127
27 INT 2 HP DAC Playback Volume 71 71

root@android:/ # tinymix 0 120 120
root@android:/ # tinymix 27 118 118

Will set the volume to maximum.

1.2 Capture Audio

The tinycap application, is routing the audio stream by default to the USB flash disk. Therefore, use a Disk-On-Key to record audio in the example below. Plug a Disk-On-Key, FAT32 formated into the USB host port. Plug an audio source (like a PC line out or smartphone line out) into the line in jack. Use the below command from hyper-terminal shell to capture the audio:

root@android:/ # tinycap /mnt/media_rw/usbdisk/test0.wav 

Hit CTRL-C after couple of seconds or more.

1.3 Playing sample .wav file

root@android:/ # tinyplay /mnt/media_rw/usbdisk/test0.wav  

2 USB OTG as a device (ADB)

Test the OTG as a device using Android ADB tool.
On target:
Under devloper option enable ADB debugguing

On Host:

$ sudo out/host/linux-x86/bin/adb kill-server
$ sudo out/host/linux-x86/bin/adb start-server
$ sudo out/host/linux-x86/bin/adb devices
$ sudo out/host/linux-x86/bin/adb shell

3 USB OTG as a host

Use an external HUB. Plug into it a Disk-On-Key, mouse and keyboard.

Make sure with the Android GUI that they are functional. Test USB Stick with:

# dd if=/dev/zero of=/dev/sdb bs=128K count=10000

In VAR-DVK-SOLO and VAR-DVK-DUAL the USB OTG port is configured as OTG.
In VAR-DVK-MX6 the USB OTG port is configured as device. To configure it as host a change in the device tree is required.


Plug a mouse into all 3 ports and make sure it is working.

Use an external HUB. Plug into it a Disk-On-Key, mouse and keyboard.
Plug it into all 3 ports and make sure all 3 devices are functioning.


5.1 Install tools on host

$ sudo add-apt-repository ppa:nilarimogard/webupd8
$ sudo apt-get update
$ sudo apt-get install android-tools-fastboot
$ sudo apt-get install android-tools-adb android-tools-fastboot

5.2 Flash target eMMC

Make sure you built Android for emmc

In case you already have partitions on the eMMC you can skip the next step.

$ sudo `which fastboot` flash mbr  emmc_mbr.img

The mbr need to be collected once of an eMMC formatted target. You can install the eMMC for the fisrt time by using our nand-recovery utility.

$ dd if=/dev/mmcblk1 of=emmc_mbr.img bs=512 count=1
If you write the MBR reset the board and enter again to fastboot before you try to flash the other images.

Boot the target press spacebar to stop at u-boot and run "fastboot". From KitKat build folder

$ sudo `which fastboot` flash boot out/target/product/var_mx6/boot-som-solo-vsc.img
$ sudo `which fastboot` flash recovery out/target/product/var_mx6/recovery-som-solo-vsc.img
$ sudo `which fastboot` flash system out/target/product/var_mx6/system.img
$ sudo `which fastboot` reboot

You need to pick and choose the right image for your development system. Follow the link for more information. Available Images


Plug an HDMI cable before power-on. U-Boot will automatically detect the HDMI cable and modify the bootargs to switch to HDMI.

6.1 Audio over HDMI

Download and install SoundAbout:

pm install /mnt/media_rw/usbdisk/apk/

Use the GUI to set the service as foreground and select the audio over HDMI.

7 External LVDS display

The current Linux kernel is device tree based kernel. In order to switch LVDS display setting a change in the kernel device tree is required.

8 Ethernet

Just plug a cable into the system


9.1 Setup

By default this steps are not required.

VAR-SOM-MX6 V1.x (WiLink6): First time need to set mac address to be used automatically

$ mount -o remount,rw /system 
$ calibrator set nvs_mac /system/etc/firmware/ti-connectivity/wl1271-nvs.bin 00:00:00:00:00:00

VAR-SOM-MX6 V2.X (WiLink8): First time need to select your correct device

  • Select your WL183x p/n:
  • Make sure the wifi is off
$ mount -o remount,rw /system 
$ cd /etc/wifi/wlconf
$ . ./ wl1831
select one out of : WL1831, WL1833, WL1835, WL1837.
As a result some additional information may be required like 1/2 antenna connected

9.2 Test

Use the Android GUI to enable and connect to a WIFI AP.


Use the Android GUI to enable.

Test with Bluetooth mouse and Bluetooth keyboard.

11 Camera

Use the Android GUI to activate and test the camera. You can take a picture and send it over Bluetooth to a PC host.


First time boot of Android must be with camera module installed. If you booted without the camera module installed Android will mark the system as "no camera". In such a case you need to re flash the Android and first time boot it with camera installed.


$ busybox fdisk -ul /dev/block/sda

In the above commands you will see SCSI status and device partition table.

If the device is FAT32 formated Android will auto mount it.

13 Serial port

pm install /mnt/media_rw/usbdisk/apk/SerialPort_1.1.apk You can download it from the Google play store. Set the device to ttymxc2 and baudrate to 115200. You can shortcut pins 2&3 and test with loopback option or connect to anther host and use the console to send receive characters.

14 RTC (Real Time Clock)

Disable the auto clock sync from the Android GUI.

# date "123123592017.00"
# hwclock --systohc (or: hwclock -f /dev/rtc0 --systohc)

You can also set the clock via the GUI and check it later.

In any method power down the board and wait 5 minutes. After that power up the board and check the the clock is correct.

15 CAN bus

We added support for CAN bus in the kernel and the support library layer.

Connect 2 boards. Each board JP26 connect to the other with the right cable. Set the 2 boards:

# ip link set can0 up type can bitrate 1000000
# ifconfig can0 up up

On board 1:

# candump can0

On board 2:

# cansend can0 500#1E.10.10