Embedded module TQMa6ULxL - YOCTO Linux BSP documentation

Starterkit Interfaces and Functions

Audio

Audio Connector Overview

Connector Function
X19 Microphone
X20 Line In
X21 Line Out
The microphone input is not supported in the current BSP version.

Audio Connector Location

Play Audio on MBa6ulx

A simple test sound can be played with the commandline tool speaker-test.
Headphones or active speakers have to be connected to X21 on MBa6ulx. 

speaker-test --channels 2 --test wav

You can also play your own audio files using aplay 

aplay <file>

e.g. 

aplay test.wav
Please notice that no audio test files are available in the default image.

Record Audio via Line-In on MBa6ulx 

arecord -f cd test.wav
The audio settings can be altered using amixer or alsamixer

Ethernet

The STKa6ulxL Starterkit provides two Gigabit Ethernet interfaces.

U-Boot

In U-Boot eth0 is configured as default interface. The IP configuration can be done statically or by a DHCP server in the network.

IP configuration via DHCP

For a configuration via a DHCP server, use the dhcp command in U-Boot.

Static IP configuration For a static IP configuration the following, U-Boot environment variables must be set: 

setenv ipaddr <ipaddr> 
(e.g.: setenv ipaddr 192.168.100.111)
setenv netmask <netmask> 
(e.g.: setenv netmask 255.255.255.0)

Linux

Both Ethernet interfaces are activated and configured by systemd-network. The configuration files for interfaces are located in /lib/systemd/network/ these configuration files can be altered to customize the default interface configuration. A documentation of the configuration files can be found here.

eth0 10-eth0.network
eth1 10-eth1.network

For a temporary static configuration the ip command can be used, below some useful ip commands are listed:

Activate a specific interface
e.g. eth0 

ip link set eth0 up


Disable a specific interace
e.g. eth0 

ip link set eth0 down


Show ip address for a specific interface
e.g. eth0 

ip addr show eth0


Show statistic for a specific interface
e.g. eth0 

 
ip -s link show eth0


Set ip address for a specific interface
e.g. eth0 

ip addr add 192.168.1.100/24 dev eth0


Show statistic of all interfaces

ip -s link


Set default gateway for a specific interfaces
e.g. set gateway ip 192.168.1.1 for eth0 

ip route add default via 192.168.1.1 dev eth0

If a DHCP server is available in the network environment the ip configuration can be received from it. To do so execute the udhcpc command, by default eth0 is used.
To configure another interface via dhcp the parameter -i followed by the interface name e.g. eth1 must be given.
e.g. eth1 

udhcpc -i eth1

I2C

An overview of the onboard i2c devices is available here

U-Boot

Select i2c bus device 

i2c dev 3

Show all devices connected to the i2c bus currently selected: 

i2c probe

Linux

Detect all devices connected to a i2c bus: 

i2cdetect 3

LVDS

TQ offers an optional LVDS Display kit for the STKa6ulxL. Each Display can be used on its own by using the corresponding device tree. To allow reusage, the support for each display is separated in a dtsi fragment.

Interface Device tree
LVDS0 imx6ul-mba6ulx-lga-lvds.dtb

To bring up the display the U-Boot environment has to be adapted accordingly.

  1. Interrupt boot process in U-boot
  2. Set U-Boot environment variable fdt_file with the command setenv fdt_file <device tree> (e.g. setenv fdt_file imx6ul-mba6ulx-lga-lvds.dtb)
  3. Save the envrionment by executing the saveenv command

RTC

To set the hardware clock to the actual time and date use the following commands: 

date -s [YYYY.]MM.DD-hh:mm[:ss]
hwclock -w

SPI

The MBa6ulx has one SPI interfaces. They can be found on the extension headers and can be tested with a loopback test.

SPI Overview

Interface linux filesystem
SPI2 /dev/spidev1.0

Loopback Test SPI Interface

For the loopback test you need a bridge between SPI_MOSI and SPI_MISO:

  • SPI2: bridge between X5_35 (SPI2_MOSI) and X5_36 (SPI2_MISO)
echo -n -e "\x01\x0F" | spi-pipe -d <spi interface> -s 10000000 | hexdump
(e.g. echo -n -e "\x01\x0F" | spi-pipe -d /dev/spidev1.0 -s 10000000 | hexdump)

Temperature Sensors

The STKa6ULxL has two temperature sensors, one is located on the TQMa6ULxL SOM and the other is locates on the MBa6ULx baseboard.

Device I²C Address
TQMa6ULxL 0x1A
MBa6ULx 0x19

Read TQMa6ULxL Temperature Sensor 

cat /sys/devices/soc0/soc/2100000.aips-bus/21f8000.i2c/i2c-3/3-001a/hwmon/hwmon0/temp1_input

Read MBa6ULx Temperature Sensor 

cat /sys/devices/soc0/soc/2100000.aips-bus/21f8000.i2c/i2c-3/3-0019/hwmon/hwmon1/temp1_input

Read CPU internal Temperature Sensor
The i.MX6UL CPU has an internal TMU that supports one thermal zones, it can be read by the commands below: Thermal zone0 

cat /sys/devices/virtual/thermal/thermal_zone0/hwmon2/temp1_input

USB

With lsusb you can see all connected usb devices. To mount a partition of an usb stick you can excute mount /dev/<partition> <mount dir> (e.g. mount /dev/sdb1 /mnt). This will mount the first partition of sdb to /mnt. To unmount the device execute umount <mount dir> (e.g. umount /mnt).

User LED

The MBa6ulx has two user controllable LEDs, the behavior of these LEDs can be selected by several triggers.

User LED Overview

Reference LED name color linux filesystem
V900 led1 green /sys/class/leds/led1
V901 led2 green /sys/class/leds/led2

User LED Location

The user LED's are located in /sys/devices/soc0/gpio-leds/leds.
To change the behaviour a specific LED, the value in the file trigger must be overwritten.

The following values are valid:

For example set the trigger of led1 to heartbeat 

echo heartbeat > /sys/class/leds/led1/trigger

  • Last modified: 2022/09/17 13:06