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LAUNCHCC3235MOD: Datetime is not retained after a hardware reset

Sundaresan Thangeswaran1
Intellectual 410 points
Part Number: LAUNCHCC3235MOD
Other Parts Discussed in Thread: CC3200

Hi,

I am using Launchpad with the provisioning demo code of SDK 5.20. I set up the new time using the internal webserver. After I restarted the device, it showed the default date 01/01/2013 00:00:01. Could you please help me to retain the date after the reset?

Regards,

Sundar

  • 0
    Guru 80045 points

    Hi Sundar,

    This is expected behaviour. The PRCM RTC registers will be cleared on reset, or if power is lost. RTC registers are retained during hibernation.

    If you want have current time after reset, you can synchronise time using NTP protocol or you can connect external RTC with own battery backup to CC3235.

    Jan

  • 0 in reply to Jan D
    Intellectual 410 points

    Hi Jan,

    Thank you so much for the reply. 

    We have previously used cc3200 for our IOT devices, and it does not require current datetime to make the enterprise (PEAP-MSCHAP) WIFI connection to the local network.

    After connecting to the network, We will get the datetime from NTP server.

    But the new version of device CC3235 does not able to connect to the same network, if the module don't have correct date time. Is this the expected behavior? If this is the expected, Could you please tell us how to fix this issue since we cannot get the correct datetime from NTP server before able to connect to the network.

    Regards,

    Sundar

  • 0 in reply to Sundaresan Thangeswaran1
    Guru 80045 points

    Hi Sundar,

    Yes, this is expected behaviour. Expiration of certificates for EAP security is validated at CC32xx (CC3220 and CC3235) devices. There is multiple ways how to deal with this:

    • use external RTC to maintain time
    • before EAP connection set time by different way (e.g. using AP mode)
    • when certificate/private key and CA files are uploaded you can parse this file to get expiration time. After that you can set time into RTC when certificate is not expired. There is no direct support for this way. You will need to this by your own code.
    • you can disable validation against CA file. This will disable validation of expiration EAP certificate as well. This approach is not recommended because this is a security risk. This can be done before manual EAP connection (using sl_WlanConnect() API) only, using this code

    caDis = 0;
retVal = sl_WlanSet(SL_WLAN_CFG_GENERAL_PARAM_ID, SL_WLAN_GENERAL_PARAM_DISABLE_ENT_SERVER_AUTH, 1, &caDis);

    btw ... CC3235 have same limitation as CC3200 in term of EAP security. For RAIUS authentication can be used TLS 1.0 only. TLS 1.2 is not supported for EAP. This can be interoperability issue at meny EAP networks, because many companies does not allow to use TLS 1.0.

    Jan

  • 0 in reply to Jan D
    Intellectual 410 points

    Hi Jan,

    Thank you for the answer. If my EAP CA certificate is valid from 01/16/2024 to 01/16/2031, I can set any date between those dates that will make the handshake successful. 

    correct me if it is wrong.

    Regards,

    Sundar

  • +1 in reply to Sundaresan Thangeswaran1
    Guru 80045 points

    Hi Sundar,

    Yes, this should work.

    But be aware that settings such time, may to affect validation of other certificates used for sokcet (TLS) connections.

    Jan