IOT-GATE-IMX8PLUS and SBC-IOT-IMX8PLUS: Debian Linux: How-To Guide
Contents
Overview
The example run-time Linux filesystem image for the CompuLab IOT-GATE-IMX8PLUS Internet of Things Gateway and SBC-IOT-IMX8PLUS Internet of Things Single Board Computer is based on Debian GNU/Linux Bullseye. The default Debian buster Linux image includes more than 650 software packages. Among them:
- Core system
- Debian package management system
- SSH server and client
- PulseAudio configuration and usage utilities
- NetworkManager
- ModemManager
- Bluez5 Bluetooth tools and daemons
- Docker
Connection and Login
This Debian rootfs comes with a default sudo user compulab. User's assword has to be set at the very first login:
Debian GNU/Linux 11 iot-gate-imx8plus ttymxc1 iot-gate-imx8plus login: compulab You are required to change your password immediately (administrator enforced). New password: Retype new password:
To login into the Linux system, use a terminal emulator as described here, or connect through the network (ssh).
Package Management
The IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS Debian Linux image includes everything required to use the Debian package management utilities.
Use apt and dpkg for managing software packages.
Device Serial Number and Configuration
Product information is stored in on-board EEPROM.
- To read the product serial number, issue the folowing command:
compulab@iot-gate-imx8plus:~$ cat /proc/device-tree/baseboard-sn
- To read the product configuration part number, issue the following command:
compulab@iot-gate-imx8plus:~$ cat /proc/device-tree/baseboard-options
Docker
The Docker Engine is preinstalled.
- The following command downloads a test image and runs it in a container. The container sample prints a message and exits.
compulab@iot-gate-imx8plus:~$ sudo docker run -it ubuntu ... 0;root@b053b4b3817d: /root@b053b4b3817d:/# cat /etc/issue Ubuntu 22.04.1 LTS \n \l ...
Cellular Modem
IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS cellular interface is implemented with a mini-PCIe cellular modem module and a
nano-SIM socket. To set up IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS for cellular functionality, install an active SIM card into
the front panel nano-SIM socket (U10).
Cellular module should be installed into mini-PCIe socket P3.
ModemManager
The ModemManager can be used to log into almost any Internet Service Provider with simple configuration setup.
In the following example:
- Replace ISP-APN with the APN name of the cellular provider.
compulab@iot-gate-imx8plus:~$ sudo nmcli connection add type gsm ifname '*' con-name CellularCon apn <ISP-APN>
- Connect cellular network
compulab@iot-gate-imx8plus:~$ sudo nmcli connection up CellularCon
- Disconnect cellular network
compulab@iot-gate-imx8plus:~$ sudo nmcli connection down CellularCon
WiFi
IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS features an optional 802.11ax WiFi interface, implemented with the Intel WiFi 6 AX210 module.
The NetworkManager can be used to manage WiFi interface.
Enable/Disable WiFi Interface
- To enable WiFi interface:
compulab@iot-gate-imx8plus:~$ sudo nmcli radio wifi on
- To disable WiFi interface:
compulab@iot-gate-imx8plus:~$ sudo nmcli radio wifi off
Network Scanning
- Sample WiFi scanning:
compulab@iot-gate-imx8plus:~$ nmcli dev wifi list
- The output will show the list of Access Points and Ad-Hoc cells in range.
Connecting to Access Point
In the following example:
- Replace <SSID> and <PASSWORD> with the actual access point parameters:
compulab@iot-gate-imx8plus:~$ sudo nmcli device wifi connect <SSID> password <PASSWORD> name WifiCon
- Disconnect wireless network:
compulab@iot-gate-imx8plus:~$ sudo nmcli connection down WifiCon
- Connect wireless network again:
compulab@iot-gate-imx8plus:~$ sudo nmcli connection up WifiCon
Creating Access Point
In the following example:
- Replace <SSID> and <PASSWORD> with desired access point parameters:
sudo nmcli device wifi hotspot ssid <SSID> password <PASSWORD> con-name HotspotCon
- Disable wireless AP:
compulab@iot-gate-imx8plus:~$ sudo nmcli connection down HotspotCon
- Enable wireless AP again:
compulab@iot-gate-imx8plus:~$ sudo nmcli connection up HotspotCon
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:
compulab@iot-gate-imx8plus:~$ sudo ip link set can0 type can bitrate 1000000
- Enable the CAN interface:
compulab@iot-gate-imx8plus:~$ sudo 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):
compulab@iot-gate-imx8plus:~$ sudo cansend can0 111#1122334455667788
- Send extended CAN frame (on the first device):
compulab@iot-gate-imx8plus:~$ sudo cansend can0 11111111#1122334455667788
- CAN frames (extended mode) generator, random payload, interval between two successive flames 50 msec:
compulab@iot-gate-imx8plus:~$ sudo cangen -g 50 -e -D r -v can0 ... can0 1E5137F4#0F.4D.8B.7A.25.4D.DB.21 can0 1B6C965C#8C.DE.96.58.69.5F.D5.26 can0 1BD23086#8D.DB.C4.3E.81.57.BA.34 can0 127B2322#F4.16.31.2E.34.04.62 can0 1A6366DB#A8.73.C0.37.D8 can0 03620EE4# can0 023AC34D#C6.08.BD.2A.04.B3.BF.43 can0 1C19AD2E#09.C1.B3.26.23.E5.6A.5A can0 02BCA994#48.32.46.7C.F0.3F.29.1E can0 08104C67#59.9F.FE.44 can0 1C280582#6F.D4.9C.38.A5.28.A3 can0 0BC219EE#D9.2C.05 can0 04AA80B8#A1.93 can0 1A3E2392#AD.98 can0 0025950E#E3.99.38 ...
- Dump all received data frames as well as error frames:
compulab@iot-gate-imx8plus:~$ sudo candump any,0:0,#FFFFFFFF ... can0 0CC89C1A [1] 51 can0 0A097EFB [0] can0 02B59BD5 [5] 68 6F 47 64 D9 can0 03743A1E [7] FA BF E4 38 3E BF C8 can0 13C9B644 [8] 30 FB 60 6F E1 FC 55 65 can0 018A8975 [0] can0 0C9C8179 [0] can0 011F5D90 [6] 65 DB DD 5A AA F9 can0 07B7FD18 [6] CC 96 26 1D 13 7C can0 1FBD7177 [8] 69 BF 8D 1E 4C 0D 73 02 can0 107A7E2D [2] 25 D3 can0 12B9E279 [8] 89 77 B7 54 BD 98 83 06 can0 112A44EA [8] 9E 95 D9 6B 60 CE B4 52 can0 0ADF9869 [3] C8 A0 27 can0 1580C274 [5] B2 7A F7 43 04 can0 06DDDBCC [7] AF 19 88 04 E4 D8 95 can0 127FA5CE [8] F7 54 57 20 45 17 3D 12 can0 09A37893 [0] can0 01BA4332 [6] 0B AF 0C 2E AB 25 can0 180A8AD5 [5] 68 BE F7 5A C0 can0 06DC994E [7] 20 9E E9 7B B8 31 BC ...
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.
compulab@iot-gate-imx8plus:~$ wget https://www.modbusdriver.com/downloads/modpoll.tgz -P /tmp/ ... compulab@iot-gate-imx8plus:~$ sudo 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:
compulab@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:
compulab@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:
compulab@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:
compulab@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:
compulab@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:
compulab@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:
compulab@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:
compulab@iot-gate-imx8plus:~$ sudo iotg-imx8plus-dio -o 2 1
- Read IN3 pin state (LO):
compulab@iot-gate-imx8plus:~$ sudo iotg-imx8plus-dio -i 3 0
RTC
IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS RTC is implemented with the AM1805 real-time clock (RTC) chip.
Back-up battery keeps the RTC running to maintain clock and time information whenever the main power supply is not present.
Accessing and setting the RTC
- To access the RTC time and date run:
compulab@iot-gate-imx8plus:~$ sudo hwclock 2022-08-04 12:38:10.577874+00:00
- To set the date and write it into the RTC do the following:
compulab@iot-gate-imx8plus:~$ sudo date -s "31 Dec 2021 10:00:00" Fri Dec 31 10:00:00 IST 2021 compulab@iot-gate-imx8plus:~$ sudo hwclock -w compulab@iot-gate-imx8plus:~$ sudo hwclock 2021-12-31 10:00:08.317403+02:00
Watchdog
IOT-GATE-IMX8PLUS / SBC-IOT-IMX8PLUS watchdog function is implemented with the i.MX8M Plus watchdog.
By default watchdog is not configured.
compulab@iot-gate-imx8plus:~$ systemctl show | grep RuntimeWatchdog
RuntimeWatchdogUSec=0
The value RuntimeWatchdogUSec=0 means watchdog logic is disabled: no watchdog device is opened, configured, or pinged
Watchdog configuration
- Edit /etc/systemd/system.conf file to configure watchdog related parameters, in particular RuntimeWatchdogSec and ShutdownWatchdogSec
- Reboot the device
- Verify watchdog configuration
compulab@iot-gate-imx8plus:~$ systemctl show | grep RuntimeWatchdog
RuntimeWatchdogUSec=10s
Watchdog testing
- Run the following command to simulate kernel panic:
compulab@iot-gate-imx8plus:~$ sudo su
root@iot-gate-imx8plus:/home/compulab# echo "c" > /proc/sysrq-trigger
- As a result, the watchdog is not fed and the system reboots after 10 sec.
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):
compulab@iot-gate-imx8plus:~$ LED=Red_2
- Turn the LED ON
compulab@iot-gate-imx8plus:~$ echo "1" | sudo tee -a /sys/class/leds/${LED}/brightness
- Turn the LED OFF
compulab@iot-gate-imx8plus:~$ echo "0" | sudo tee -a /sys/class/leds/${LED}/brightness
- Set LED's trigger
compulab@iot-gate-imx8plus:~$ echo "heartbeat" | sudo tee -a /sys/class/leds/${LED}/trigger