Software User Guide

Required Hardware

  • Development kit: AD-SWIOT1L-SL Software-configurable Analog and Digital I/O with 10BASE-T1L

  • Power supplies: 24V power supply at minimum 2A

  • Programmer: MAX32625PICO or any other similar programmer supporting the SWD interface

System Setup

  • Connect the AD-SWIOT1L-SL to the AD-T1LUSB2.0-EBZ using the single pair Ethernet cable.

  • Connect the AD-T1LUSB2.0-EBZ to your PC using a usb cable

  • Connect the 24 V power supply to the AD-SWIOT1L-SL.

Windows User Guide

  • Connect the AD-SWIOT1L-SL to your Windows PC using the AD-T1LUSB2.0-EBZ.

To communicate with the AD-SWIOT1L-SL board, you need to configure your Windows PC’s network adapter with a static ip address in the same subnet as the board e.g 192.168.97.1/24

The AD-SWIOT1L-SL board uses the static ip address: 192.168.97.40

Configure Windows Network Adapter

  1. Open the Control Panel and navigate to “Network and Internet”

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  1. Select your Ethernet interface and click “Edit” to modify the ip settings

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  1. Set the ip settings to manual and configure the following values:

    • ip address: 192.168.97.1

    • Subnet mask: 255.255.255.0

    https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/ad-swiot1l-sl/software-guide/3.png

    Save the changes and close the network settings.

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  1. Open a command prompt and verify the new assigned ip address using the command:

    ipconfig
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  1. Ping the AD-SWIOT1L-SL board to verify connectivity:

    ping 192.168.97.40
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linux User Guide

  • Connect the AD-SWIOT1L-SL to your linux PC using the AD-T1LUSB2.0-EBZ

To communicate with the AD-SWIOT1L-SL board, you need to configure your linux PC’s network adapter with a static IP address in the same subnet as the board e.g 192.168.97.1/24.

Configure linux Network Adapter

  1. Identify the network interface corresponding to the AD-T1LUSB2.0-EBZ using the command:

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/ad-swiot1l-sl/software-guide/linux_1.png

  1. Configure the network interface with a static ip address:

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/ad-swiot1l-sl/software-guide/linux_2.png
https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/ad-swiot1l-sl/software-guide/linux_3.png

  1. Verify you can ping the AD-SWIOT1L-SL board:

ping 192.168.97.40
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The Scopy AD-SWIOT1L-SL Plugin

For detailed information on how to use the AD-SWIOT1L-SL Scopy plugin, including configuration, operation modes, and available instruments, please refer to the comprehensive Scopy SWIOT1L Plugin Documentation.

Using the IIO interface

The firmware is based on a no-OS implementation of the IIO framework from the linux kernel, which offers similar functionalities. Thus, the board may be configured through the use of pyadi-iio API.

In order to get the pyadi-iio drivers follow the next steps:

  1. Clone the pyadi-iio repository:

    git clone https://github.com/analogdevicesinc/pyadi-iio

  2. Follow the installation steps provided in the pyadi-iio README.

    ### this might need changing once swiot is merged into main

  3. Checkout the swiot branch:

    git checkout swiot

  4. Install the pyadi-iio package:

    pip install .

SWIOT device configuration overview

This section provides a high-level overview of how the firmware manages device configuration. Detailed field device usage information is presented in the following sections. When powered, the SWIOT1L board operates in one of two states, each identified by a distinct IIO context:

  • Config: All channels are in a high impedance state. Users can configure channel functions and route each SWIOT1L channel to either the MAX14906 or AD74413R device using the swiot virtual device.

    Note

    When entering this state from the runtime mode, some of the device configurations will reset. The configuration selected in this context will help in generating the runtime IIO context.

Open the IIO context by running iio_info with the appropriate URI:

iio_info -u ip:192.168.97.40

The iio context should look similar to this:

Library version: 0.24 (git tag: c4498c2)
Compiled with backends: local xml ip usb serial
IIO context created with network backend.
Backend version: 1.1 (git tag: 0000000)
Backend description string: 192.168.97.40 no-OS swiot-rebase-lwip-eda9f736d-modified
IIO context has 2 attributes:
   ip,ip-addr: 192.168.97.40
   uri: ip:192.168.97.40
IIO context has 2 devices:
   iio:device0: swiot
      0 channels found:
      27 device-specific attributes found:
            attr  0: reset ERROR: No such file or directory (2)
            attr  1: serial_id value: 80a4-44044-1f003-2d8104ff-bf
            attr  2: mode value: config
            attr  3: mode_available value: config runtime
            attr  4: identify ERROR: No such file or directory (2)
            attr  5: ext_psu value: 1
            attr  6: signal_mse value: 32
            attr  7: ch0_enable value: 0
            attr  8: ch1_enable value: 0
            attr  9: ch2_enable value: 0
            attr 10: ch3_enable value: 0
            attr 11: ch0_function value: high_z
            attr 12: ch1_function value: high_z
            attr 13: ch2_function value: high_z
            attr 14: ch3_function value: high_z
            attr 15: ch0_device value: ad74413r
            attr 16: ch1_device value: ad74413r
            attr 17: ch2_device value: ad74413r
            attr 18: ch3_device value: ad74413r
            attr 19: ch0_function_available value: high_z voltage_out
               current_out voltage_in current_in_ext current_in_loop
               resistance digital_input digital_input_loop
               current_in_ext_hart current_in_loop_hart
            attr 20: ch1_function_available value: high_z voltage_out
               current_out voltage_in current_in_ext current_in_loop
               resistance digital_input digital_input_loop
               current_in_ext_hart current_in_loop_hart
            attr 21: ch2_function_available value: high_z voltage_out
               current_out voltage_in current_in_ext current_in_loop
               resistance digital_input digital_input_loop
               current_in_ext_hart current_in_loop_hart
            attr 22: ch3_function_available value: high_z voltage_out
               current_out voltage_in current_in_ext current_in_loop
               resistance digital_input digital_input_loop
               current_in_ext_hart current_in_loop_hart
            attr 23: ch0_device_available value: ad74413r max14906
            attr 24: ch1_device_available value: ad74413r max14906
            attr 25: ch2_device_available value: ad74413r max14906
            attr 26: ch3_device_available value: ad74413r max14906
      No trigger assigned to device
   trigger0: sw_trig
      0 channels found:
      No trigger on this device

  • Runtime: All channel functions are configured, and the devices are operational and out of reset. In this state, the devices can sample or output signals, report faults, and allow register read/write operations. Channel direction and functions remain fixed during runtime mode, except for the AD74413R’s diagnostic channels, which can still be modified.

Field Device Configuration and Usage

This section details how the IIO interface may be used to configure and sample data from the field devices. The system has the following IIO devices:

SWIOT Virtual Device

Field devices must have their channels configured before being used in the runtime context. This is done through the swiot virtual IIO device, which is present in both the config and runtime IIO contexts.

Device Attributes

  • reset: Write any value to reset the firmware. Cannot be read.

  • serial_id: Unique ID specific to the microcontroller. Read-only.

  • mode: Reflects the system’s state (config or runtime). Can be written to change state. Possible values are in mode_available. Writing the current state value is a no-op. Invalid values are ignored.

  • mode_available: Valid mode values: config, runtime.

  • identify: Write any value to blink LED2. Useful for identifying which board has a specific context (or IP) in a multi-board network.

  • ext_psu: Mirrors the external power supply switch. A value of 1 does not guarantee power supply connection or 156W capability. Read-only. Possible values:

    • 0: Field devices powered only by LT8304 (via 24V terminal block) and/or LTC9111 (via SPoE)

    • 1: MAX14906 powered directly by external power supply

  • signal_mse: Single Pair Ethernet signal quality indicator. Read-only.

  • chX_enable: Channel-specific enable condition. X refers to the SWIOT1L terminal block channel number (0-based). When set to 0, the channel remains in high impedance state regardless of other attributes. Values: 0 or 1.

  • chX_function: I/O function for a SWIOT1L terminal block channel. Specific to AD74413R or MAX14906 depending on chX_device. Possible values in chX_function_available. Important: Set chX_device first, as the value is validated when written. Otherwise -EINVAL (-22) is returned.

  • chX_function_available: Available values for chX_function. Read-only.

  • chX_device: Field device controlling the terminal block channel. Possible values in chX_device_available.

  • chX_device_available: Available values for chX_device: ad74413r, max14906.

Configuration Example

In the pyadi-iio example script, channel functions are configured using the channel_enable, channel_config, and channel_device lists:

"""
Possible values:
- max14906 selected as device: input, output
- ad74413r selected as device: voltage_out, current_out,
  voltage_in, current_in_ext, current_in_loop,
  resistance, digital_input, digital_input_loop,
  current_in_ext_hart, current_in_loop_hart
"""
channel_config = ["voltage_in", "current_in_ext", "current_out", "output"]
# Possible values: 0, 1
channel_enable = [1, 1, 1, 1]
# Possible values: "ad74413r", "max14906"
channel_device = ["ad74413r", "ad74413r", "ad74413r", "max14906"]

This configuration means:

  • Channel 1: Routed to AD74413R channel 1, measuring input voltage

  • Channel 2: Routed to AD74413R channel 2, measuring input current

  • Channel 3: Routed to AD74413R channel 3, measuring voltage from current-limited output

  • Channel 4: Routed to MAX14906 channel 4, configured as digital output

To ensure config context is selected:

swiot.mode = "config"

Configuration sequence using swiot attributes:

swiot.ch0_device = channel_device[0]
swiot.ch0_function = channel_config[0]
swiot.ch0_enable = channel_enable[0]
swiot.ch1_device = channel_device[1]
swiot.ch1_function = channel_config[1]
swiot.ch1_enable = channel_enable[1]
swiot.ch2_device = channel_device[2]
swiot.ch2_function = channel_config[2]
swiot.ch2_enable = channel_enable[2]
swiot.ch3_device = channel_device[3]
swiot.ch3_function = channel_config[3]
swiot.ch3_enable = channel_enable[3]

Important

Set chX_device before chX_function, otherwise an error will occur.

The indexes in these lists correspond to the terminal block channel number (0-based).

When channels are configured, the firmware automatically places the corresponding parallel channel in high impedance to avoid conflicts.

Switching Contexts

To switch from config to runtime mode:

swiot.mode = "runtime"

After writing this attribute, the IIOD server restarts, causing the connection to drop and the IIO context to be destroyed. The new context must be recreated:

ad74413r = adi.ad74413r(uri=dev_uri)
max14906 = adi.max14906(uri=dev_uri)
adt75 = adi.lm75(uri=dev_uri)
swiot = adi.swiot(uri=dev_uri)

The runtime context also contains the field devices, which can be used to sample data.

Controlling the MAX14906

Direct Register Access

Device registers can be read or written using the IIO direct register access interface:

  • Reading: value = max14906.reg_read(0x1)

  • Writing: max14906.reg_write(0x1, 0xff)

Warning

This method should be used with caution as it overwrites firmware settings. Updating an existing value requires a read→apply mask→write sequence.

Using Channel Attributes

The MAX14906 has the following IIO channels, corresponding to the 4 physical channels:

voltageX (input or output):

  • raw: 0 or 1, representing low/high state. For outputs:

    max14906.channels["voltage3"].raw = 1  # or 0

    Can be read in both input and output modes:

    state = max14906.channels["voltage3"].raw

  • scale: Constant value of 1

  • offset: Constant value of 0

  • current_limit (output only): Set from predefined values in current_limit_available:

    max14906.channels["voltage3"].current_limit = 130

  • current_limit_available: 600, 130, 300, 1200 (mA)

  • do_mode (output only): Configure output driver:

    max14906.channels["voltage3"].do_mode = "High_side"

  • do_mode_available: High_side, High_side_2x_inrush, Push_pull_clamp, Push_pull

  • IEC_type (input only): Setup digital-IO input type

  • IEC_type_available: Type_1_3, Type_2

Note

For comprehensive descriptions, refer to the MAX14906 datasheet.

Controlling the AD74413R

Direct Register Access

Device registers can be read or written using the IIO direct register access interface:

  • Reading: value = ad74413r.reg_read(0x1)

  • Writing: ad74413r.reg_write(0x1, 0xff)

Warning

This method should be used with caution as it overwrites firmware settings.

Channel Configurations

Each AD74413R channel can be configured with one of these functions: voltage_out, current_out, voltage_in, current_in_ext, current_in_loop, resistance, digital_input, digital_input_loop, current_in_ext_hart, current_in_loop_hart.

1. Voltage Input

Creates one IIO channel:

Input voltage:

Attribute

Description

Access

Shared

raw

Value 0-8191 (DAC code). Vout = (raw + offset) × scale (mV)

R/W

No

scale

Constant: 1.342 mV/LSB

R

No

offset

Constant: 0

R

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes
2. Current Output

Creates two IIO channels:

Input voltage (measures voltage output by DAC):

Same attributes as Voltage Input configuration above.

Output current:

Attribute

Description

Access

Shared

raw

Value 0-8191 (DAC code). Iout = (raw + offset) × scale (mA)

R/W

No

scale

Constant: 0.003051 mA/LSB

R

No

offset

Constant: 0

R

No

slew_en

Enable slew rate control (uses slew_rate and slew_step)

R/W

No

slew_rate

Configure DAC output slew rate

R/W

No

slew_rate_available

Available slew_rate values

R

Yes

slew_step

Configure DAC output slew step

R/W

No

slew_step_available

Available slew_step values

R

Yes
3. Voltage Output

Creates two IIO channels:

Input current (measures current output by DAC):

Attribute

Description

Access

Shared

raw

Value 0-65535 (ADC code). I = (raw + offset) × scale (mA). Positive = sourced, negative = sinked

R/W

No

scale

Constant: 0.000762951 mA/LSB

R

No

offset

Constant: -32768

R

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes

Output voltage:

Attribute

Description

Access

Shared

raw

Value 0-8191 (DAC code). Vout = (raw + offset) × scale (mV)

R/W

No

scale

Constant: 1.22070 mV/LSB

R

No

offset

Constant: 0

R

No

slew_en

Enable slew rate control (uses slew_rate and slew_step)

R/W

No

slew_rate

Configure DAC output slew rate

R/W

No

slew_rate_available

Available slew_rate values

R

Yes

slew_step

Configure DAC output slew step

R/W

No

slew_step_available

Available slew_step values

R

Yes
4. Current Input Externally Powered

Creates one IIO channel:

Input current:

Attribute

Description

Access

Shared

raw

Value 0-65535 (ADC code). I = (raw + offset) × scale (mA)

R/W

No

scale

Constant: 0.000381476 mA/LSB

R

No

offset

Constant: 0

R

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes
5. Current Input Loop Powered

Creates two IIO channels:

Input current (measures current sourced by AD74413R):

Attribute

Description

Access

Shared

raw

Value 0-65535 (ADC code). I = (raw + offset) × scale (mA)

R/W

No

scale

Constant: 0.000381476 mA/LSB

R

No

offset

Constant: 0

R

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes

Output current (sets current limit sourced by AD74413R):

Attribute

Description

Access

Shared

raw

Value 0-8191 (DAC code). Iout = (raw + offset) × scale (mA)

R/W

No

scale

Constant: 0.003051 mA/LSB

R

No

offset

Constant: 0

R

No

slew_en

Enable slew rate control (uses slew_rate and slew_step)

R/W

No

slew_rate

Configure DAC output slew rate

R/W

No

slew_rate_available

Available slew_rate values

R

Yes

slew_step

Configure DAC output slew step

R/W

No

slew_step_available

Available slew_step values

R

Yes
6. Current Input Loop Powered with HART Compatibility

The channels and their attributes are the same as Current Input Loop Powered mode.

7. Current Input Externally Powered with HART Compatibility

The channels and their attributes are the same as Current Input Externally Powered mode.

8. Resistance

Creates one IIO channel:

Resistance:

Attribute

Description

Access

Shared

raw

Value 0-65535 (raw ADC result register value)

R/W

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes
9. Digital Input

Creates one IIO channel:

Voltage input:

Attribute

Description

Access

Shared

raw

Value 0 or 1 (comparator output)

R/W

No

scale

Constant: 1

R

No

offset

Constant: 0

R

No

threshold

Threshold value in millivolts for comparator

R/W

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes
10. Digital Input Loop Powered

Creates two IIO channels:

Voltage input:

Attribute

Description

Access

Shared

raw

Value 0 or 1 (comparator output)

R/W

No

scale

Constant: 1

R

No

offset

Constant: 0

R

No

threshold

Threshold value in millivolts for comparator

R/W

No

sampling_frequency

Samples per second (divided by enabled channels)

R/W

No

sampling_frequency_available

4800, 1200 (no filter); 20, 10 (filtered)

R

Yes

Current output (sets current limit sourced by AD74413R):

Attribute

Description

Access

Shared

raw

Value 0-8191 (DAC code). Iout = (raw + offset) × scale (mA)

R/W

No

scale

Constant: 0.003051 mA/LSB

R

No

offset

Constant: 0

R

No

slew_en

Enable slew rate control (uses slew_rate and slew_step)

R/W

No

slew_rate

Configure DAC output slew rate

R/W

No

slew_rate_available

Available slew_rate values

R

Yes

slew_step

Configure DAC output slew step

R/W

No

slew_step_available

Available slew_step values

R

Yes

Sampling Data from the AD74413R

Example: Sampling Buffered Data

The following example demonstrates how to use pyadi-iio to sample buffered data from the AD74413R:

ad74413r.rx_enabled_channels = ["voltage0"]
ad74413r.sample_rate = 4800
ad74413r.rx_buffer_size = 4800
data = ad74413r.rx()

You can change the sampling channel to another input channel:

ad74413r.rx_enabled_channels = ["current0"]

The channel must be configured appropriately in the SWIOT1L configuration. Samples are stored in the data array.