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CC33XX-SOFTWARE: WLAN TX test results in Calibrator mode affected by normal operating mode

Part Number: CC33XX-SOFTWARE
Other Parts Discussed in Thread: CC3301

Tool/software:

Dear TI experts,

I have a custom PCB including CC3301 + Linux host. I've been using Calibrator tool test commands to measure WLAN RF performance in continuous TX mode with maximum TX power. During these tests I've noticed some failing EVM results and messy-looking IQ constellations with the highest data rates (11g / 54Mbps and 11n / MCS7), but there is some strange behavior depending on what I do before turning on the Calibrator tool mode:
If I first connect CC3301 in normal STA mode to my measurement equipment (R&S CMW500) that is acting as AP, then turn off the normal operating mode and start the Calibrator tool, I get PASS results with exactly the same test setup and test commands. If I then reboot my device and start the Calibrator tool again without first connecting in normal STA mode, my TX test results are failing again.

Please see attached test reports with and without prior normal operating mode connection. Could you please help me to figure out how to get consistent TX test results with Calibrator tool?

Here is the SW information printed by the Linux host during power up:
[   15.586575] wlcore: Wireless driver version 1.7.0.114
[   15.603779] wlcore: Wireless firmware version 1.7.0.120
[   15.607562] wlcore: Wireless PHY version 1.2.36.5.22.66

And here is the wpa_supplicant.conf file that I have used for normal operating mode:

	ctrl_interface=/var/run/wpa_supplicant
	ctrl_interface_group=0
	update_config=1

	network={
		ssid="CMW-AP"
		key_mgmt=NONE
	}


Calibrator tool commands are included in test reports. Please let me know if you need any more information.


Best regards,
Kaisa

WLAN g_non-sig TX_CH 1,3,6,8,11,13_6,24,54Mbps_2024-08-09_09-31-02_129_Straight after reboot.pdf

WLAN g_non-sig TX_CH 1,3,6,8,11,13_6,24,54Mbps_2024-08-09_09-06-22_126_After normal operating mode connection.pdf

  • Hi Kaisa,

    Let me work with our team to help get you the correct answer here. We will review your results and respond back later this week. 

  • Hi Kaisa,

    I recommend downloading the latest SDK from here:https://www.ti.com/tool/CC33XX-SOFTWARE

    While in PLT mode (for Calibrator tool) PHY calibration has to be done manually - you can find a more up to date calibrator tool guide in the latest SDK drop that covers this command. If you aren't calibrating then its possible that the higher rates have degraded EVM performance. 

    While in a system config (set up as a STA), the CC3301 device will auto calibrate - this is likely why when you switch from that mode to PLT you are seeing the optimized performance. Rebooting will clear the RAM and thus lose the saved calibration data.

  • Hi Dylan,

    thank you for your quick response. I can find the "calibrate" button in the SimpleLink Wi-Fi Toolbox UI, but could you still advise how to do the calibration when sending PLT commands via Linux host automatically as shown in my test reports? I can't find any information about any kind of calibration from SimpleLink CC33xx Calibrator Tool User's Guide that I have used to create required test commands.

    Best regards,

    Kaisa

  • Hey Kaisa,

    Once you install the newest SDK, you will see the docs folder in the install directory. In that docs, folder you will find the Linux User Guide which contains our newest calibrator tool guide:

  • Hi Dylan,

    thank you for these instructions, it would have been very difficult to find the latest calibrator tool guide without it. Even with these detailed instructions I feel it was difficult to find it. I hope that you will still also update the "traditional" documents, so that there is no need to install some SDK every time to get access to one user guide.

    Anyway, I now get consistent TX test results in calibrator mode, so my problem is fixed. Thank you!

    Best regards,
    Kaisa

  • Hey Kaisa,

    Thanks for the good feedback, we are currently working on a solution to make this process easier for customers. For now, I'm happy to know your issue has been resolved.