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LAUNCHXL-CC1310: Symbol Rate limitation of Wide Band DSSS limitation

Yuning Wang
Prodigy 30 points
Part Number: LAUNCHXL-CC1310
Other Parts Discussed in Thread: CC1310, CC1350, CC1101

Tool/software:

Hi, 

When I use SmartRF Studio7, I could only see the symbol rate is up to 480K Baud. 

Does CC1310 support higher symbol rate of wide-band DSSS mode ? and how to implement ?  

Thanks 

  • 0
    TI__Genius 17955 points

    Hi,

    For FSK the maximum data rate is 500 kbps on the CC1310 unless the High Speed Mode (HSM) or General High Speed (GHS) modes are used, but they do not support WB-DSSS at the time of writing.

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 30 points

    Hi Zack, 

    Thanks for the reply.

    I'm trying to increase the symbol rate of WB-DSSS mode. do you know the highest symbol rate which can support for WB-DSSS ? 

    does the HSM support WB-DSSS ? I did not mean the options in SmartStudio. 

    Thank you again.

    Yuning. 

  • 0 in reply to Yuning Wang
    TI__Genius 17955 points

    Hi Yuning,

    500 kbps is the highest symbol rate that has been characterised as 480 kbps was the highest symbol rate it was developed for.

    HSM does not support WB-DSSS, it is the least flexible PHY as it must use exact settings without any modification. GHS also does not support WB-DSSS.

    You would need to either increase the RXBW setting and experiment yourself; it has not been tested with higher symbol rates and there are not plans to at this time (unless there is a large justification for it).

    You can use the following App Note for general guidance: SWRA682 (Finding Settings for new PHYs for the CC13x0 and CC13x2 Family): https://www.ti.com/lit/swra682

    One potential avenue that you could also explore is that the CC131x/CC135x devices (except for CC1310/CC1350) have a higher clock rate, so the potential for higher WB-DSSS symbol rate support is greater, but again untested.

    Regards,

    Zack 

  • 0 in reply to ZC
    Prodigy 30 points

    Hi Zack, 

    Thanks for the info. 

    It came out another question about WB-DSSS. 

    1. In Smart Stuidio, If we selected the spreading of WB-DSSS to 1, does it mean the difference between the one I selected and the original 2-GFSK is the FEC enabled or not ?  (of course the symbol rate and the some other frequency related parameters are different ), but they are using the same channel coding method, is that correct ? 

    2. If I used the "500 Kbps, 2-GFSK, 175 Khz deviation ", how could I enable FEC ? 

    Thanks

    Yuning 

  • 0 in reply to Yuning Wang
    TI__Genius 17955 points

    Hi Yuning,

    You can find details of the WB-DSSS mode here: SWRA591 (Wide-Band DSSS Mode for FCC Digital Transmission Systems Using CC13x0): https://www.ti.com/lit/swra591

    From SWRA591, you would be most interested in Section 2 and 3:

    The SmartRF Studio settings are detailed in Table 3:

    For regular 2-GFSK, the only FEC available is CC1101 compatible FEC, detailed here: https://dev.ti.com/tirex/explore/content/simplelink_cc13x0_sdk_4_20_02_07/docs/proprietary-rf/proprietary-rf-users-guide/proprietary-rf/cc1101-migration.html?highlight=forward%20error%20correction#forward-error-correction-fec 

    That might fulfil your requirements. The details of that implementation are found in SWRA113 (FEC Implementation): https://www.ti.com/lit/swra113

    Otherwise, the other modes that have FEC enabled are WB-DSSS and LRM. 

    Regards,

    Zack