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CC3120MOD: WLAN connection time

Ilian Chakarov
Expert 2170 points
Part Number: CC3120MOD
Other Parts Discussed in Thread: CC3120

Hi,

we are using CC3120MOD in a very low power device.

For this reason the connection to the WLAN (AP) and IP address acquisition (DHCP is used).

I tested some brands of AP (D-LINK, TP-LINK, MIKROTIK,...).

The time for WLAN connection is different for different brands, but for MIKROTIK is terrible - from 3.5 to 4.5 seconds.

For the other brands the time is under 3sec.

The type of connection policy ,which is used is "Auto", because the device is movable and can change the AP.

From AP point of view for fast connection DTIM time interval and Beacon time interval should be fast (DTIM = 1, beacon time interval - 100ms) to expect fast connection.

Can you suggest please, hoe to improve the connection time to the AP?

Best regards,

Ilian

  • 0
    Prodigy 240 points

    Hi Ilian,

    There is very little that can be done on the application side to change the connection speed unfortunately.

    It would be best if you captured the NWP logs, so that we can see exactly is causing the slow connection speed, and whether there is something internal to the NWP that can be modified. The instructions for that can be found in section 20.1 of the NWP user's guide:

    www.ti.com/lit/swru455

    Do note that as you are using the CC3120, the NWP log output is enabled automatically, and there isn't anything you need to do on your host to enable the NWP log output.

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Expert 2170 points

    Hi Michael,

    Thanks for the answer!

    In the CC3120MOD  pin52 (TEST_62) , should be used to capture the log?

    Best regards,

    Ilian

  • 0 in reply to Ilian Chakarov
    TI__Mastermind 40965 points

    Hi Ilian,

    Yes, that is the correct pin to use.

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Expert 2170 points

    Hi Michael,

    Thanks!

    One more question according WLAN connection time.

    Our device is movable, for this reason I use wlan connection policy Auto. The application know, when the device is in movable state and when is not movable. Is it good solution (from NWP perspective) to change the wlan connection policy to be Auto, when device is movable and Auto+Fast, when the device is not movable. Is this dynamically change the policy is good idea or can be a problem for NWP?

    Best regards,

    Ilian

  • 0 in reply to Ilian Chakarov
    TI__Mastermind 40965 points

    Hi Ilian,

    There are no issues with dynamically changing the policy, and it might make sense if you know that your device is going to move out of range of the BSSID that is saved as the fast connect profile.

    That being said, whenever you change a persistent setting such as the connection policy you will perform a write to the serial flash in the CC3120MOD. The serial flash has a finite number of writes that it is rated for in its lifetime, so you should not change the connection policy extremely often otherwise you may exhaust the flash before the end of your product's lifecycle.

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Expert 2170 points

    Hi Michael,

    Thanks!

    In our case, this can happen relatively often, for this reason may be the better solution is to work only with Fast connection policy, like most universal solution for movable device.

    Best regards,

    Ilian

  • 0 in reply to Ilian Chakarov
    TI__Mastermind 40965 points

    Hi Ilian,

    No, I don't think the fast connection policy is the best as a universal setting. With fast connect, the device will always try to reconnect to the last connected BSSID. If your device has moved out of range, then it will fail.

    In this case, the device will usually use the auto connect policy as a fallback, and connect to the profiles saved to the device. However, if only fast connect is enabled this will not happen. So the most universal policy is keeping the device on Auto connect.

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Expert 2170 points

    Hi Michael,

    yes you are right, it was my writing mistake, I use  Auto policy like most universal.

    Best regards,

    Ilian