3 Replies Latest reply on Apr 17, 2020 5:14 AM by SheetalJ_96

    【CYBT-343026-01】About power control step

    YoJa_3107936

      Hi everyone

       

      The customer would like to confirm the below questions.

       

      1, According to datasheet, there is a "PowerControlStep" item in Txpower of Classic Bluetooth,

      but there is no such item in the TxPower column of BLE.

      Could you tell me the reason?

       

      2, Minimum is 2dB, so does it mean that the minimum step can be changed in 2dB units?

      >https://community.cypress.com/community/wiced-studio-blueooth/wiced-studio-bluetooth-forums/blog/2018/01/24/configuring-transmit-tx-power-in-cyw20706

      > Power should be a multiple of 4 from +8 dBm to -16 dBm, i.e. power can be +8, +4, 0, -4, -8, -12, -16 dBm.

      But on this site, I can only set it in units of 4dB,

      so the PowerControlStep min 2dB in the data sheet can't be realized?

      Please teach if there is another method to change the output.

       

      3, Regarding the TxPower in the data sheet, you can see the notation of

      odd output of EDR 9dBm (typ), BLE 9dBm (max).

      What kind of command is required to realize the data sheet output?

       

      Thanks

      Yang

        • 1. Re: 【CYBT-343026-01】About power control step
          SheetalJ_96

          Hi Yang,

           

          As mentioned in datasheet (refer above table), typical Tx power for EDR is 9 dBm. 2 is the power control step, not the Tx power. But practically, you can set the Tx power with step of 4 as mentioned in the blog Configuring Transmit (Tx) power on the CYW20706.

          You can use the APIs mentioned in this blog to set this Tx power.

           

          For BLE, we have mentioned the Tx power in datasheet:

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          • 2. Re: 【CYBT-343026-01】About power control step
            YoJa_3107936

            Hi SheetalJ_96

             

             

            Thank you for your cooperation.

             

            I have already checked the DataSheet but you haven't answered my question.

            Change the question.

             

            1. There is no [Power Controle Step] item in the "Chipset BLE RF Specifications" table, could you tell me why?

             

            2. >2 is the power control step, not the Tx power. But practically, you can set the Tx power with step of 4 as mentioned in the blog.

            I know [power control step] is not [Tx power]. You mean that I can't set the Tx power with step of 2 as mentioned in the blog, is it right?

             

            3. I want to test TxPower about EDR 9dBm (typ), BLE 9dBm (max).

            What value should be set?

            >wiced_result_t wiced_bt_dev_set_adv_tx_power( int power );

            >wiced_result_t wiced_bt_dev_set_tx_power( wiced_bt_device_address_t bd_addr , int power );

             

            Thanks

            Yang

            • 3. Re: 【CYBT-343026-01】About power control step
              SheetalJ_96

              Hi Yang,

               

              Following are the answers to your queries:

               

              1. I am not sure why the power control step is not mentioned for BLE specifications. But you can change it in step of 4 as mentioned in blog.

              2. Yes right.

              3. By default, the Tx power for BLE is 9 dBm. I think you should get value 9 if you try reading it. However, using the API, not sure what value should be given. Can you try setting it to 8 or 12 & then check how much you are getting? Is there any specific requirement for your application for 9 dBm?

               

              Regards,
              Sheetal

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