Overview

The example run-time Yocto Linux image for the CompuLab IOT-GATE-IMX8PLUS and SBC-IOT-IMX8PLUS was generated with Kirkstone Yocto build. The image includes the needed drivers and utilities to operate the hardware components of the IOT-GATE-IMX8PLUS/SBC-IOT-IMX8PLUS.

The default Kirkstone Yocto image includes many software packages. Among them:

Core system
SSH server and client
ConnMan
ModemManager
Bluez5 Bluetooth tools and daemons
SocketCAN
Minicom

Connection and Login

This Yocto rootfs comes with an empty root password. No password is required for login.

To login into the Linux system, you may use a terminal emulator as described here, or connect through the network (ssh).

The following examples assume root user.

Connectivity

IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS Yocto Linux Image includes ConnMan is a command-line network manager designed for use with embedded devices and fast resolve times. It can be used for managing all type of network interfaces:

Wired
Wireless
Cellular

Start ConnMan service prior to accessing network interfaces

root@iot-gate-imx8plus:~# systemctl start connman

Display supported technologies

root@iot-gate-imx8plus:~# connmanctl technologies
/net/connman/technology/cellular
  Name = Cellular
  Type = cellular
  Powered = True
  Connected = True
  Tethering = False
  TetheringFreq = 2412
/net/connman/technology/ethernet
  Name = Wired
  Type = ethernet
  Powered = False
  Connected = False
  Tethering = False
  TetheringFreq = 2412
/net/connman/technology/wifi
  Name = WiFi
  Type = wifi
  Powered = True
  Connected = False
  Tethering = False
  TetheringFreq = 2412
/net/connman/technology/bluetooth
  Name = Bluetooth
  Type = bluetooth
  Powered = False
  Connected = False
  Tethering = False
  TetheringFreq = 0

Ethernet

Enable/Disable Ethernet Interfaces

To enable Ethernet interfaces:

root@iot-gate-imx8plus:~# connmanctl enable ethernet

To disable Ethernet interfaces:

root@iot-gate-imx8plus:~# connmanctl disable ethernet

Enable/Disable Ethernet Connections

To display Ethernet Connections:

root@iot-gate-imx8plus:~# connmanctl services | grep ethernet

Example (both Ethernet ports are connected to a LAN):

root@iot-gate-imx8plus:~# connmanctl services | grep ethernet

*AR Wired                ethernet_0001c030d7c3_cable

*AR Wired                ethernet_0001c031ffe2_cable

To enable Ethernet interfaces:

root@iot-gate-imx8plus:~# connmanctl enable <ethernet service name>

To disable Ethernet interfaces:

root@iot-gate-imx8plus:~# connmanctl disable <ethernet service name>

Example:

root@iot-gate-imx8plus:~# connmanctl disconnect ethernet_0001c031ffe2_cable

Disconnected ethernet_0001c031ffe2_cable

root@iot-gate-imx8plus:~# connmanctl services | grep ethernet

*AR Wired                ethernet_0001c030d7c3_cable

*A  Wired                ethernet_0001c031ffe2_cable

root@iot-gate-imx8plus:~# connmanctl connect ethernet_0001c031ffe2_cable

Connected ethernet_0001c031ffe2_cable

Cellular Modem

Enable/Disable Cellular Interface

To enable Ethernet interfaces:

root@iot-gate-imx8plus:~# connmanctl enable cellular

To disable Ethernet interfaces:

root@iot-gate-imx8plus:~# connmanctl disable cellular

Enable/Disable Cellular Connections

To display Cellular Connections:

root@iot-gate-imx8plus:~# connmanctl services | grep cellular

Example:

root@iot-gate-imx8plus:~# connmanctl services | grep cellular

*AR 425007               cellular_425071043611161_context1

To connect Cellular network:

root@iot-gate-imx8plus:~# connmanctl enable <cellular service name>

To disconnect Cellular network:

root@iot-gate-imx8plus:~# connmanctl disable <cellular service name>

WiFi

Enable/Disable WiFi Interface

To enable WiFi interface:

root@iot-gate-imx8plus:~# connmanctl enable wifi

To disable WiFi interface:

root@iot-gate-imx8plus:~# connmanctl disable wifi

Network Scanning

Sample WiFi scanning:

root@iot-gate-imx8plus:~# connmanctl scan wifi

Display list of Access Points and Ad-Hoc cells in range

root@iot-gate-imx8plus:~# connmanctl services | grep wifi

Example:

   Compulab-Guest       wifi_8c1d96f18740_436f6d70756c61622d4775657374_managed_psk

...

   AP-Free              wifi_8c1d96f18740_6b77696b2d6d6f62_managed_none

Where a service name pattern is as shown below:

wifi_<hashlocal>_<hashremote>_managed_<encrption>

Connecting to Open Access Point

In the following example replace <hashlocal> and <hashremote> with the actual service parameters.

Connect wireless network:

root@iot-gate-imx8plus:~# connmanctl connect wifi_<hashlocal>_<hashremote>_managed_none

Disconnect wireless network:

root@iot-gate-imx8plus:~# connmanctl disconnect wifi_<hashlocal>_<hashremote>_managed_none

Connecting to Protected Access Point

For protected access points some information (like password) has to be provided to the ConnMan daemon.

The commands in this section show how to run connmanctl in interactive mode, it is required for running the agent command.

Start interactive mode:

root@iot-gate-imx8plus:~# connmanctl

Sample WiFi scanning (wait for scan completed):

connmanctl> scan wifi

Display a list of services:

connmanctl> services

   Compulab-Guest       wifi_8c1d96f18740_436f6d70756c61622d4775657374_managed_psk

...

   AP-Free              wifi_8c1d96f18740_6b77696b2d6d6f62_managed_none

Register the agent to handle user requests:

connmanctl> agent on

Connect to one of the protected services. Replace <hashlocal> and <hashremote> with the actual service parameters:

connmanctl> connect wifi_<hashlocal>_<hashremote>_managed_psk

Agent RequestInput wifi_<hashlocal>_<hashremote>_managed_psk

  Passphrase = [ Type=psk, Requirement=mandatory ]

Passphrase?

Provide any information required by the daemon to complete the connection. The information requested may vary depending on the type of network.

Quit:

connmanctl> quit

Disconnect wireless network:

root@iot-gate-imx8plus:~# connmanctl disconnect wifi_<hashlocal>_<hashremote>_managed_psk

Connect wireless network again:

root@iot-gate-imx8plus:~# connmanctl connect wifi_<hashlocal>_<hashremote>_managed_psk

CAN

IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS features one CAN 2.0B port implemented with i.MX8M Plus CAN controller.
CAN bus signals are routed to industrial I/O connector P8.

CAN interface configuration

Configure the CAN interface bit-rate to 1 Mbits/sec:

root@iot-gate-imx8plus:~# ip link set can0 type can bitrate 1000000

Enable the CAN interface:

root@iot-gate-imx8plus:~# ip link set can0 up

Send/Receive packets

Use cansend and candump utilities to send and receive packets via CAN interface.

Send standard CAN frame (on the first device):

root@iot-gate-imx8plus:~# cansend can0 111#1122334455667788

Send extended CAN frame (on the first device):

root@iot-gate-imx8plus:~# cansend can0 11111111#1122334455667788

CAN frames (extended mode) generator, random payload, interval between two successive flames 50 msec:

root@iot-gate-imx8plus:~# cangen -g 50 -e -D r -v can0
...
...

Dump all received data frames as well as error frames:

root@iot-gate-imx8plus:~# candump any,0:0,#FFFFFFFF
...
...

Industrial Interfaces

IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS implements industrial interfaces with four I/O slots (IE) that can be fitted with up-to four different I/O modules. Slots are referred to as A, B, C and D.

Available I/O modules types:

RS232 (2-wire)
RS485 (half duplex)
Digital I/O (4x DI + 4x DO)

IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS industrial I/O signals are routed to Industrial I/O Connector (P8)

Please refer to Industrial I/O Connector pin-out for more details.

So far industrial I/O modules do not require any special configuration.

RS232

RS232 function is implemented with MAX3221 (or compatible) transceiver interfaced with i.MX8M Plus UART ports.

RS232 modules can be installed into I/O slots A, B and C. Up to three RS232 modules can be installed simultaneously.

Configuration and Access

Once properly installed on a specific I/O slot, RS232 interface can be accessed in Linux via ttyRS232_X tty device, where X is a slot name: A, B, C.

RS485

RS485 function is implemented with MAX13488 (or compatible) transceiver interfaced with i.MX8M Plus UART ports.

RS485 modules can be installed in I/O slots A, B and C. Up to three RS485 modules can be installed simultaneously.

Configuration and Access

Once properly installed on a specific I/O slot, RS485 interface can be accessed in Linux via ttyRS485_X tty device, where X is a slot name: A, B, C.

Modbus RS485

The following example demonstrates how to use RS485 module installed into industrial I/O slot A in a Modbus RS485 Network. IOTG-IMX8PLUS performs as a Master device and queries XY-MD02 temperature and humidity sensor.

Software installation

Download and install modpoll - a command line based Modbus master simulator and test utility.

root@iot-gate-imx8plus:~# wget https://www.modbusdriver.com/downloads/modpoll.tgz -P /tmp/
...
root@iot-gate-imx8plus:~# tar -xvf /tmp/modpoll.tgz -C /opt/
...

Device connection

Connect XY-MD02 sensor to appropriate Industrial I/O connector pins as below:

A+: XY-MD02 A+ to IOT-GATE-iMX8PLUS / SBC-IOT-IMX8PLUS P8-01
B-: XY-MD02 B- to IOT-GATE-iMX8PLUS / SBC-IOT-IMX8PLUS P8-03

--------------------                                  -------------------------
|                  |                                  |                       |
|                  *--(+)---< <------------- 5V-30V   |     IOTG-IMX8PLUS     |
|                  |                                  |   (SBC-IOT-IMX8PLUS)  |
|                  *--(-)---< <-------------- GND     |------  ------------   |
| XY-MD02 (RS485)  |                                  |     |==| IE-RS485 |   |
|                  *--(A+)--< <---...---> >---(1)---*-|     |  ------------   |
|                  |                                  | P8  |     Slot A      |
|                  *--(B-)--< <---...---> >---(3)---*-|     |                 |
|                  |                                  |------                 |
--------------------                                  -------------------------

Read data

Read temperature once:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 2 -1 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave...
[2]: 250

Poll temperature:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 2 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave... (Ctrl-C to stop)
[2]: 254
-- Polling slave... (Ctrl-C to stop)
[2]: 254
-- Polling slave... (Ctrl-C to stop)
[2]: 254
...

Read humidity once:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 3 -1 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 3, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave...
[3]: 515

Poll humidity:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 1 -r 3 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 3, count = 1
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave... (Ctrl-C to stop)
[3]: 894
-- Polling slave... (Ctrl-C to stop)
[3]: 895
-- Polling slave... (Ctrl-C to stop)
[3]: 896
...

Read temperature & humidity once:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 2 -r 2 -1 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 2
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave...
[2]: 263
[3]: 606

Poll temperature & humidity:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 3 -c 2 -r 2 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC4
Slave configuration...: address = 1, start reference = 2, count = 2
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave... (Ctrl-C to stop)
[2]: 263
[3]: 545
-- Polling slave... (Ctrl-C to stop)
[2]: 263
[3]: 543
-- Polling slave... (Ctrl-C to stop)
[2]: 263
[3]: 542
...

Read slave address, baudrate, temperature & humidity corrections:

root@iot-gate-imx8plus:~# /opt/modpoll/arm-linux-gnueabihf/modpoll -b 9600 -p none -t 4 -c 4 -r 258 -1 /dev/ttyRS485_A
modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2021 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC3
Slave configuration...: address = 1, start reference = 258, count = 4
Communication.........: /dev/ttyRS485_A, 9600, 8, 1, none, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave...
[258]: 1
[259]: 9600
[260]: 0
[261]: 0

Digital I/O

Digital I/O module features 4 digital inputs and 4 digital outputs and can be installed into slot D. Four digital inputs are implemented with the CLT3-4B digital termination following EN 61131-2. Four digital outputs are implemented with the VNI4140K solid-state relay following EN 61131-2.

Digital I/O module requires an external voltage supply up to 24V to be properly connected. Please refer to Industrial I/O Connector pin-out for more details.

Configuration and Access

Use iotg-imx8plus-dio utility to access digital inputs and outputs.

The example below shows how to access Digital inputs and outputs.

Drive OUT2 pin HI:

root@iot-gate-imx8plus:~# iotg-imx8plus-dio -o 2 1

Read IN3 pin state (LO):

root@iot-gate-imx8plus:~# iotg-imx8plus-dio -i 3
0

LEDs

IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS features two user Bi-Color (Red + Green) LEDs found on front panel.
LEDs are controlled via GPIO pins and can be accessed via sysfs interface.

LEDs are referred to as Green_1, Red_1, Green_2 and Red_2
Choose a LED (LED2 Red in this example):

root@iot-gate-imx8plus:~# LED=Red_2

Turn the LED ON

root@iot-gate-imx8plus:~# echo "1" | tee -a /sys/class/leds/${LED}/brightness

Turn the LED OFF

root@iot-gate-imx8plus:~# echo "0" | tee -a /sys/class/leds/${LED}/brightness

Set LED's trigger

root@iot-gate-imx8plus:~# echo "heartbeat" | tee -a /sys/class/leds/${LED}/trigger

Video Playback

The operation below requires root access.

IOT-GATE-IMX8PLUS and SBC-IOT-IMX8PLUS are built around UCM-iMX8M-Plus SoC that features 1080p60 H.264, VP8 video decoding capabilities. Before starting video playback, please, ensure that the display is connected to the board.

The following commands can be used to start video playback (1.mov is a media file):

gst-play

root@iot-gate-imx8plus:~# gst-play /path/to/1.mov

gplay-1.0

root@iot-gate-imx8plus:~# gplay-1.0 /path/to/1.mov

gst-launch

This method is for advanced users. Please study this document before the start: i.MX8GStreamerUserGuide.pdf

root@iot-gate-imx8plus:~# gst-launch-1.0 -v filesrc location=/path/to/1.mov ! qtdemux name=d.video_0 ! h264parse ! avdec_h264 ! autovideosink

IOT-GATE-IMX8PLUS and SBC-IOT-IMX8PLUS: Yocto Linux: How-To Guide

Contents

Overview

Connection and Login

Connectivity

Ethernet

Enable/Disable Ethernet Interfaces

Enable/Disable Ethernet Connections

Cellular Modem

Enable/Disable Cellular Interface

Enable/Disable Cellular Connections

WiFi

Enable/Disable WiFi Interface

Network Scanning

Connecting to Open Access Point

Connecting to Protected Access Point

CAN

CAN interface configuration

Send/Receive packets

Industrial Interfaces

RS232

Configuration and Access

RS485

Configuration and Access

Modbus RS485

Software installation

Device connection

Read data

Digital I/O

Configuration and Access

LEDs

Video Playback

Navigation menu

Search