CC2564C: CC2564C - How to change TX output power

Hello,

I have a question regarding TI bluetooth chip CC2564C. I'm using it in combination with STM3240G-eval board (CC256x STM32 Bluetopia SDK v4.2.1.0)

I've tried to change output power within HFP_AG sample demo: HCI_VS_DRPb_Set_Class2_Single_Power.

However, with the spectrum analyzer I cannot see any difference between standard settings and custom settings (-50 dBm).

I added the following code :

int InitializeApplication(HCI_DriverInformation_t *HCI_DriverInformation, BTPS_Initialization_t *BTPS_Initialization)
{
   int ret_val = APPLICATION_ERROR_UNABLE_TO_OPEN_STACK;

   /* Next, makes sure that the Driver Information passed appears to be */
   /* semi-valid.                                                       */
   if((HCI_DriverInformation) && (BTPS_Initialization))
   {
      /* Try to Open the stack and check if it was successful.          */
      if(!OpenStack(HCI_DriverInformation, BTPS_Initialization))
      {
        
           /* Lower Output Power */
          ret_val = VS_Set_Max_Output_Power(BluetoothStackID, 0);
          if(!ret_val)
          {
             Display(("\r\n   VS_Set_Max_Output_Power success \r\n"));
          }
          else
          {
             Display(("\r\n   VS_Set_Max_Output_Power fail %d \r\n", ret_val));
          }
          /*... rest of the InitializeApplication */

....

}

I can see the command executed with TI HCI Logger:

Default settings for TX output power (limited in software to 10 dBm):

Set TX output power to -50 dBm - no impact on TX output power (measured with spectrum analyzer)

Does anybody have an idea why I see no difference with the spectrum analyzer regarding the TX output power?

Thanks and Regards

Tim