IOT-DIN-IMX8PLUS: Debian Linux: I/O Modules Guide
Contents
Overview
IOT-DIN-IMX8PLUS supports up to eight I/O Expansion Modules that can be stacked with the main gateway in order to extend the feature set of the system. A gateway assembly includes one gateway (the left most unit) and multiple I/O Expansion modules. Module stacking is done from left to right. Up to 8 I/O Expansion Modules can be supported in one gateway assembly. The modules are interconnected using Compulab’s proprietary StackLink expansion connector that extends a series of the IOT-DIN-IMX8PLUS interfaces, creating a chain of peripherals.
I/O Expansion Modules Stacking Rules
- There can be up-to 8 I/O Expansion Modules in one assembly
- IFM-WB modules can only be installed in position A (next to main gateway)
- There can be up-to 3 (in total) modules of types IFM-RS485, IFM-RS232, IFM-WB
- There can be up-to 4 IFM-DI8O8 modules
- There can be only 1 IFM-ADC8 module
I/O Modules Configuration
I/O expansion modules are managed as a front-plane of virtual slots that map device access files to physical I/O modules per their positions in the stack.
During O/S boot IOT-DIN-IMX8PLUS automatically runs the StackLink configurator script that detects I/O modules and configures the virtual device files used to address the hardware.
The script creates the IFM front-plane file directory that includes type and access files for all populated stack slots.
IFM Front-Plane
During O/S boot the StackLink configurator script creates the IFM front-plane file directory that includes type and access files for all populated stack slots (from A to last populated slot).
/run/iotdin-imx8p/stack/frontplane
Front-plane directory structure
Example I/O modules stack:
+----------+-------+-------+-------+-------+ | Slot # | A | B | C | D | +----------+-------+-------+-------+-------+ | IFM Type | ADC8 | DI8O8 | RS485 | RS232 | +----------+-------+-------+-------+-------+
Front-plane file directory:
/run/iotdin-imx8p/stack/frontplane |-- A | |-- access | | |-- adc0 -> /sys/bus/iio/devices/iio:device0 | | `-- adc1 -> /sys/bus/iio/devices/iio:device1 | `-- type.ADC8 |-- B | |-- access | | |-- di.map | | |-- do.map | | `-- gpiochip -> /dev/gpiochip6 | `-- type.DI8O8 |-- C | |-- access | | |-- tty0 -> /dev/ttyIFM_RSx_0_0 | | |-- tty1 -> /dev/ttyIFM_RSx_0_1 | | |-- tty2 -> /dev/ttyIFM_RSx_0_2 | | `-- tty3 -> /dev/ttyIFM_RSx_0_3 | `-- type.RS485 `-- D |-- access | |-- tty0 -> /dev/ttyIFM_RSx_1_0 | |-- tty1 -> /dev/ttyIFM_RSx_1_1 | |-- tty2 -> /dev/ttyIFM_RSx_1_2 | `-- tty3 -> /dev/ttyIFM_RSx_1_3 `-- type.RS232
Stack Detection Status
StackLink configurator script provides indication of I/O modules stack detection status using IOT-DIN-IMX8PLUS power LED:
Power LED | Status | Remarks |
Blinking Blue | Recognized and valid configuration | Normal operation |
Blinking Amber | Unrecognized I/O module or invalid configuration | Check the log for details |
Stack Detection Info
StackLink configurator script stores stack detection info log in the following designated location:
/run/iotdin-imx8p/log/iotdin-imx8p.stack.log.<YYYYMMDD_HHMMSS>
Stack Troubleshooting
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DO NOT attach or detach I/O Expansion modules while the gateway is connected to DC power! Disconnect all power sources from the gateway before attaching or detaching I/O modules. |
In case of invalid IFM stack status:
- Check the stack detection log
- Double check if a desired stack conforms the Stacking Rules
- Verify proper mechanical attachment of modules
- Contact technical support
IFM Backplane
/run/iotdin-imx8p/stack/backplane
directory stores the system information about the physical hardware devices installed in the stack. These files should not be altered.
IFM-DI8O8
IFM-DI8O8 module provides an isolated block of eight digital inputs and a block of eight digital outputs.
During O/S boot IOT-DIN-IMX8PLUS will automatically detect installed IFM-DI8O8 modules and create necessary access files in the front-plane directory. For additional details please refer to the Configuration chapter.
Use diodetect command to get an overview of all available Digital Inputs and Outputs:
compulab@compulab-imx8mp:~$ /opt/iotdin-imx8p/shell/diodetect Main Gateway: DI2O2 (2x DI; 2x DO) Stack Slot B: DI8O8 (8x DI; 8x DO)
Use dioget and dioset commands to access digital inputs and digital outputs.
It is recommended to set the following alias for more convenient work:
compulab@compulab-imx8mp:~$ dioget=/opt/iotdin-imx8p/shell/dioget
compulab@compulab-imx8mp:~$ dioset=/opt/iotdin-imx8p/shell/dioset
Reading Digital Inputs
Setup alias for more convenient work:
compulab@compulab-imx8mp:~$ dioget=/opt/iotdin-imx8p/shell/dioget
compulab@compulab-imx8mp:~$ sudo ${dioget} -h Usage: dioget [options] <command> Read digital input state from a Digital I/O (DIO) module Command: -m <module> <offset> module: DIO module location: m|M - Main Gateway a|A - Virtual slot A ... h|H - Virtual slot H offset: input pin offset: <0..MaxOffset> Options: -h: display this help and exit
Example
Read state of input pin IN_4 on IFM-DI8O8 installed in slot B:
compulab@compulab-imx8mp:~$ sudo ${dioget} -m B 4
Setting Digital Outputs
Setup alias for more convenient work:
compulab@compulab-imx8mp:~$ dioset=/opt/iotdin-imx8p/shell/dioset
compulab@compulab-imx8mp:~$ sudo ${dioset} -h Usage: dioset [options] <command> Set the digital output state of a Digital I/O (DIO) module Command: -m <module> <offset> <state> module: DIO module location: m|M - Main Gateway a|A - Virtual slot A ... h|H - Virtual slot H offset: output pin offset: <0..MaxOffset> state: output pin state to be set: <0|1> Options: -h: display this help and exit
Example
Setting output pin OUT_4 to HIGH state on IFM-DI8O8 installed in slot B:
compulab@compulab-imx8mp:~$ sudo ${dioset} -m B 4 1
IFM-ADC8
IFM-ADC8 provides eight single-ended analog input channels (0-7), divided into two blocks of 4. Inputs operate between 0-10V or 4-20mA ranges for use with industrial sensors. Each block can be set into current or voltage input mode via jumper.
During O/S boot IOT-DIN-IMX8PLUS will automatically detect installed I/O modules and create necessary access files in the front-plane directory. For additional details please refer to the Configuration chapter.
Example
Рead a detected value of channel 5 of IFM-ADC8 module installed in slot A:
compulab@compulab-imx8mp:~$ X=5 ; slot=A compulab@compulab-imx8mp:~$ sudo cat /run/iotdin-imx8p/stack/frontplane/${slot}/access/adc$((X/4))/in_voltage$((X%4))_raw
IFM-RS485
IFM-RS485 I/O module provides four half-duplex RS485 ports.
During O/S boot IOT-DIN-IMX8PLUS will automatically detect installed I/O modules and create necessary access files in the front-plane directory. For additional details please refer to the Configuration chapter.
Example
For an IFM-RS485 module installed in slot C the configurator script will create the following access files:
/run/iotdin-imx8p/stack/frontplane/ |-- C | |-- access | | |-- tty0 | | |-- tty1 | | |-- tty2 | | `-- tty3 | `-- type.RS485
Use /run/iotdin-imx8p/stack/frontplane/C/access/ttyX
to access port #X
IFM-RS232
IFM-RS232 I/O module provides four 2-wire RS232 ports.
During O/S boot IOT-DIN-IMX8PLUS will automatically detect installed I/O modules and create necessary access files in the front-plane directory. For additional details please refer to the Configuration chapter.
Example
For an IFM-RS232 module installed in slot D the configurator script will create the following access files:
/run/iotdin-imx8p/stack/frontplane/ |-- D | |-- access | | |-- tty0 | | |-- tty1 | | |-- tty2 | | `-- tty3 | `-- type.RS232
Use /run/iotdin-imx8p/stack/frontplane/D/access/ttyX
to access port #X
IFM-WB
IFM-WB I/O module features one 802.11ax WiFi and one Bluetooth 5.3 BLE interfaces.
During O/S boot IOT-DIN-IMX8PLUS will automatically detect installed I/O modules and create necessary access files in the front-plane directory. For additional details please refer to the Configuration chapter.
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IFM-WB module can only be installed in position A (next to main gateway) |
For an IFM-WB module installed in slot A the configurator script will create the following access files:
/run/iotdin-imx8p/stack/frontplane/ |-- A | |-- access | | |-- bluetooth -> /sys/class/bluetooth/hci0 | | `-- wlan -> /sys/class/net/wlan0 | `-- type.WB
Example
- Display WiFi network interface info
compulab@compulab-imx8mp:~$ wlan=$(basename $(readlink -f /run/iotdin-imx8p/stack/frontplane/A/access/wlan)) compulab@compulab-imx8mp:~$ sudo ifconfig ${wlan} compulab@compulab-imx8mp:~$ sudo iwconfig ${wlan}
- Display Bluetooth interface info
compulab@compulab-imx8mp:~$ bt=$(basename $(readlink -f /run/iotdin-imx8p/stack/frontplane/A/access/bluetooth)) compulab@compulab-imx8mp:~$ hciconfig ${bt}
WiFi
Enable/Disable WiFi Interface
- To enable WiFi interface:
compulab@compulab-imx8mp:~$ sudo nmcli radio wifi on
- To disable WiFi interface:
compulab@compulab-imx8mp:~$ sudo nmcli radio wifi off
Network Scanning
- Sample WiFi scanning:
compulab@compulab-imx8mp:~$ 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@compulab-imx8mp:~$ sudo nmcli device wifi connect <SSID> password <PASSWORD> name WifiCon
- Disconnect wireless network:
compulab@compulab-imx8mp:~$ sudo nmcli connection down WifiCon
- Connect wireless network again:
compulab@compulab-imx8mp:~$ sudo nmcli connection up WifiCon
Creating Access Point
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Debian 12 ipv4 forwarding must be turned on manually |
- Enable port forwarding:
compulab@compulab-imx8mp:~$ sudo sed -i 's/^#\(net.ipv[4,6].*forward\)/\1/' /etc/sysctl.conf
- Enable wireless AP (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@compulab-imx8mp:~$ sudo nmcli connection down HotspotCon
- Enable wireless AP again:
compulab@compulab-imx8mp:~$ sudo nmcli connection up HotspotCon