Compiler/CC2652P: Change Tx power on CC2652P

Hi,

See if this helps:

 https://e2e.ti.com/support/wireless-connectivity/bluetooth/f/538/t/738259 

https://e2e.ti.com/support/wireless-connectivity/bluetooth/f/538/t/482692 

https://e2e.ti.com/support/wireless-connectivity/bluetooth/f/538/t/697671 

regards,

Hi,

I just bought a LaunchPad CC1352P-2 kit (that’s the reason for the delay in this answer) to test the change of the Tx power.

I modified the simple_peripheral_oad_offchip code example and included the change of TX power every 10 seconds. The wanted value toggles between -20 dBm and +20 dBm. 

The RSSI value is measured with a professional test equipment from Frontline.

The result is the same as explained above: the first call to HCI_EXT_SetTxPowerCmd correctly sets the initial Tx power. But subsequent calls to HCI_EXT_SetTxPowerCmd have no effect on the measured value, the TX power doesn’t change.

Thanks in advance for your response.

Regards,

Nicolas

Hi,

Can you try calling  HCIExt_EndModemTestCmd and then set new power level by calling HCI_EXT_SetTxPowerCmd.

Thanks

Hi,

Your workaround only works when the circuit remains in advertising role.

When a connection has been established, the TX power doesn't change anymore.

The CC13x2, CC26x2 SimpleLinkTM Wireless MCU Technical Reference Manual explains that the TX power can be changed by sending commands to the RF core.

Do you have a working code example which can be integrated in the simple_peripheral_oad_offchip project and

-       creates a new client instance of the RF driver with RF_open

-       sends a TX power command (CMD_SET_TX_POWER, CMD_SET_TX20_POWER )

-       closes the client instance with RF_close

Thanks in advance for your response.

Regards,

Nicolas

Hi,

You can look into the EasyLink_setRfPower(int8_t i8TxPowerDbm) API in the EasyLink example in the SDK.

The entries of the txPowerTable[] are in the file ti_radio_config.c. 

Regards,

Hi,

Did the above approach work for you?

Thanks

Hi,

I have written the following procedure:

void setTxPower(int8_t txPowerDbm) {

    rfc_CMD_UPDATE_RADIO_SETUP_t RF_cmdUpdate =

    {

       .commandNo = 0x0001,

       .__dummy0 = 0,

       .pRegOverride = NULL,

    };

    RF_Params rfParams;

    RF_Object rfObject;

    RF_Handle rfHandle;

    RF_Stat stat;

    RF_Params_init(&rfParams);

    rfHandle = RF_open(&rfObject, &RF_modeBle, (RF_RadioSetup*)&RF_cmdUpdate, &rfParams);

    if (rfHandle != NULL) {

        RF_TxPowerTable_Value value = RF_TxPowerTable_findValue(RF_BLE_txPowerTable, txPowerDbm);

        stat = RF_setTxPower(rfHandle, value);

        RF_close(rfHandle);

    }

}

The CC1352P-2 responds as follows :

-       for the Tx Power values from 14 to 20 dBm, the return value of RF_setTxPower is always RF_StatInvalidParamsError

-       for Tx Power values from -20 to 5 dBm, the return value of RF_setTxPower is RF_StatSuccess

-       for all Tx power values, the measured power value doesn’t change

Thanks in advance for your response.

Regards,

Nicolas

Hello Nicolas,

That is interesting.

1) For the easylink example the CONFIG_CC1352P_2_LAUNCHXL does not seem to be defined which might cause the tx table not being setup for PA and up to 20dBm?

if (rfHandle != NULL) {

        RF_TxPowerTable_Value value = RF_TxPowerTable_findValue(RF_BLE_txPowerTable, txPowerDbm);

if(value != RF_TxPowerTable_INVALID_VALUE) {

        stat = RF_setTxPower(rfHandle, value);

}

        RF_close(rfHandle);

2) Did you try the latest SDK? There was a fix in SDK 3.40 that might be related:

BLE_AGAMA-1471 Add support to configure Tx power in Adv. via Tx Power field in GapAdv_params_t

There were also multiple fixes related to PA mode and CC1352P in the related fix

Hello Eirik,

You mentioned the easylink example, but our software is based on the simple_peripheral_oad_offchip (version C1352P_2) example and the tx table is defined with the “normal” and the “high” PA values.

I tried with the last sdk 3.40 (both HCI_EXT_SetTxPowerCmd and my procedure named setTxPower) and the results are the same as explained above with the sdk 3.30.

Thanks in advance for your response.

Regards,

Nicolas

Hello Eirik,

I defined CC13X2P as Predefined Symbols and checked if it changes anything: nothing, always the same result as described above.

I can confirm that the index value of the tx table entry (index values between  LL_EXT_TX_POWER_MINUS_20_DBM and LL_EXT_TX_POWER_20_DBM) is passed as parameter to HCI_EXT_SetTxPowerCmd.

Thanks in advance for your response.

Regards,

Nicolas

Hello Nicolas,

Sorry for the delay,

I will find a board next week and try it out myself.

Hello Eirik,

Yes, I agree, the first call to HCI_EXT_SetTxPowerCmd correctly sets the initial Tx power. But subsequent calls to HCI_EXT_SetTxPowerCmd have no effect on the measured value, the TX power doesn’t change (already explained in my post of Jan 29th).

On the CC2652R, the power changes correctly at each call to HCI_EXT_SetTxPowerCmd.

Thanks in advance for your response.

Regards,

Nicolas

I see, my bad.

Just to clarify.

1) Do you set the power in the same manner for both CC2652R and CC2652P when testing?

2) Do you change the power while a GAP role is active or passive? 

Then I can test and file a bug if I can reproduce it on my end.

Hello Eirik,

Yes, the power is defined in the same manner for the CC2652R and CC2652P: HCI_EXT_SetTxPowerCmd is called.

In our project, the CC2652x device has the GAP role “Peripheral” and the power is changed during the “Advertising” state or when the peripheral is connected.

Thanks in advance for your response.

Regards,

Nicolas

Hello Nicolas,

I added a menu item in simple_peripheral (simplelink_cc13x2_26x2_sdk_3_30_00_03 - CC13X2P_2)  to change the output power between 0 dBm and 20 dBm during a connection and it works like a charm here. What kind of front end configuration do you use?

MENU_OBJ(spMenuSetPwr, "Set Output Power", 2, &spMenuPerConn)
MENU_ITEM_ACTION(spMenuSetPwr,0,"20 dBm", SimplePeripheral_setOutputPower)
MENU_ITEM_ACTION(spMenuSetPwr,1,"0 dBm", SimplePeripheral_setOutputPower)
MENU_OBJ_END

bool SimplePeripheral_setOutputPower(uint8 index)
{
    bool status = TRUE;
    switch(index)
    {
        case 0:
            HCI_EXT_SetTxPowerCmd(LL_EXT_TX_POWER_20_DBM);
            break;
        case 1:
            HCI_EXT_SetTxPowerCmd(LL_EXT_TX_POWER_0_DBM);
            break;
        default:
            break;
    }
    return status;
}

Hi Eirik,

Have you measured the rssi value with an iOS/Android app (e.g. nRF Connect)?

Do you notice a change in the rssi value when you modify the TX power?

For me, the rssi value doesn’t change (or only slightly) and that’s the problem.

Thanks in advance for your response.

Regards,

Nicolas