DWM ADD-ON/DWM Hardware/Integration guide

History
Issue Date	Notes
2020/11/10	New documentation layout
2021/01/19	More information about antenna calibration
2021/02/12	Non EU antenna regulator warning

Integration guide

This section provides useful information and resources that let the system designer integrate the DWM module in the application very quickly.

Typical scenario

The following picture shows the conceptual block diagram of the application where the host is an Embedded PC.

Typical scenario

Real case scenario on AXEL Lite SOM Evaluation Kit

Electrical guidelines

• Keep SDIO lines as short as possible.
• 5V and 3.3V rails can power up in any order
• Keep WIFI_EN asserted during power-up sequence

Calibration process

The radio interface of the DWM module is configured by several parameters. These parameters are set through a calibration process, that is described in detail here.

The calibration process—that produces an NVS file—is not trivial. Apart from the chip itself (Texas Instruments WL1271L in this case), it depends on:

• the antenna - a list of certified antennas and cables can be found in the TiWi Module device datasheet. Use of these antennas does not require additional FCC/IC/ETSI certifications.
• the firmware version downloaded to the chip: please refer to the proper firmware available on your Linux distribution for matching the kernel driver and run properly the calibration process
• the initialization data, typically stored in an INI file: please refer to the Laird Connectivity TiWi documentation for checking the proper INI file configuration
• the Calibrator source code here

More information about kernel driver and calibration on the Laird Support and Tools web page.

MAC address

The MAC address is set at calibration time for WLAN. To use the built in MAC address for WLAN be sure to pass a MAC address of 00:00:00:00:00:00 as a parameter to the auto-calibrate function. To set a custom MAC address for WLAN just pass the desired value into the auto-calibrate function.

NVS ready-to-use calibration files

The following links refer to specific use cases, where the resulting NVS file is provided along with DAVE Embedded Systems products integrating DWM module.

• SBC Lynx (XUELK)
• SBC Lynx (Debian)

The nvs.bin file has been created using the antenna Molex 47950-0011

Please refer to the below Laird Connectivity TiWi-BLE documentation for more information.

Tested Antennas

Following a list of tested and approved antennas:

• Laird technology 001-0001 with UFL to SMA adapter
  
  

Molex 47950-0011 valid only for No EU countries - see link

References

• Laird Connectivity TiWi-BLE documentation
• TiWi-BLE datasheet
• Antenna Design Guide
• EMC Compliance Guide
• WLAN INI all certified antennas
• WL127x Linux Calibrator

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