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 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*
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
- 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-ADC
IFM-ADC8 provides eight single-ended analog input channels, 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.
Use the following commands to read the detected values:
(table is for the IFM-ADC in stack location A)
Channel | Access File |
---|---|
1 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc0/in_voltage0_raw |
2 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc0/in_voltage1_raw |
3 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc0/in_voltage2_raw |
4 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc0/in_voltage3_raw |
5 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc1/in_voltage0_raw |
6 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc1/in_voltage1_raw |
7 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc1/in_voltage2_raw |
8 | ../run/iotdin-imx8p/stack/frontplane/A/access/adc1/in_voltage3_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