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CC3351: How to change the transmit power of the CC3351 advertising channels on the AM62 platform?

Huang Xiaoxian
Prodigy 20 points
Part Number: CC3351
Other Parts Discussed in Thread: SK-AM62B

Tool/software:

Hi Team,

I am testing the BLE functionality of the CC3351 module.

The platform I am using for testing is the SK-AM62B board with the CC3351 M.2 module. The spectrum analyzer is connected to the module’s UFL connector. The SD card image is the pre-built image under the cc33xx driver version 1.0.0.8.

I verified that the module's rf signal is normal by using the LE Transmitter Test command:

hcitool cmd 0x08 0x001e 0x00 0x25 0x00

However, I observed that the advertising channel signal is very weak after enabling BLE advertising by executing the following commands:

echo 160 >> /sys/kernel/debug/bluetooth/hci0/adv_min_interval

echo 160 >> /sys/kernel/debug/bluetooth/hci0/adv_max_interval

btmgmt -i hci0 power off

btmgmt -i hci0 le on

btmgmt -i hci0 connectable on

btmgmt -i hci0 debug-keys off

btmgmt -i hci0 sc on

btmgmt -i hci0 bondable on

btmgmt -i hci0 pairable on

btmgmt -i hci0 privacy off

btmgmt -i hci0 name cc33xxble

btmgmt -i hci0 advertising on

btmgmt -i hci0 power on

hcitool -i hci0 lerlon

When the module is connected to the BLE app, the tx power of connection channels increases to nearly 0 dBm.

I executed the HCI_EXT_SetTxPowerCmd command to change the TX power to 20 dBm:

hcitool cmd 0x3f 0x0001 3

The TX power of the connection channels increased to 15 dBm, which is what I expected.

However, when the connection is terminated, the advertising channel's TX power remains weak.

I have tried disabling and re-enabling the advertising, but the TX power remains weak.

What is the method to change the TX power of the advertising channels?

I would greatly appreciate it if you could reply to me.

Regrads,

Xiaoxian

  • 0
    TI__Genius 14601 points

    Hi,

    To change the power for advertisements the following hci command can be used 

    https://www.bluetooth.com/specifications/specs/core-specification-amended-5-4/

    Best,

    Rogelio

  • 0 in reply to RogelioD
    Prodigy 20 points

    Hi Rogelio,

    Thank you for your prompt reply.

    I have tested the LE Set Extended Advertising Parameters command, but the TX power remains at -15 dBm.

    The test commands are listed below:

    root@am62xx-evm:~# hcitool cmd 0x08 0x0036 0x00 0x13 0x00 0xa0 0x00 0x00 0xa0 0x00 0x00 0x07 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x14 0x01 0x00 0x01 0x00 0x01  //Set the tx power to 20dBm
    < HCI Command: ogf 0x08, ocf 0x0036, plen 25
    00 13 00 A0 00 00 A0 00 00 07 00 00 00 00 00 00 00 00 00 14
    01 00 01 00 01
    > HCI Event: 0x0e plen 5
    01 36 20 00 14  // Status == 0x00, Selected_TX_Power == +20
    root@am62xx-evm:~# hcitool cmd 0x08 0x0037 0x00 0x03 0x01 0x03 0x02 0x01 0x06 // Set advertising data
    < HCI Command: ogf 0x08, ocf 0x0037, plen 7
    00 03 01 03 02 01 06
    > HCI Event: 0x0e plen 4
    01 37 20 00
    root@am62xx-evm:~# hcitool cmd 0x08 0x0038 0x00 0x03 0x01 0x05 0x04 0x09 0x31 0x32 0x33 // set scan response data
    < HCI Command: ogf 0x08, ocf 0x0038, plen 9
    00 03 01 05 04 09 31 32 33
    > HCI Event: 0x0e plen 4
    01 38 20 00
    root@am62xx-evm:~# hcitool cmd 0x08 0x0039 0x01 0x01 0x00 0x00 0x00 0x00 // enable advertising
    < HCI Command: ogf 0x08, ocf 0x0039, plen 6
    01 01 00 00 00 00
    > HCI Event: 0x0e plen 4
    01 39 20 00

    The actual output power is as follows:

    I have also tried setting the TX power to 0 dBm, but the result is the same as above.

    Are there any other configurations that affect the advertising channel TX power?

    Could you please test and let me know if you observe the same result on your side?

    Thank you for your assistance.

    Best regards,

    Xiaoxian

  • 0 in reply to Huang Xiaoxian
    TI__Genius 14601 points

    Hi,

    I will try to test and replicate the behavior. I will follow up once I have results.

    Best,

    Rogelio

  • 0 in reply to RogelioD
    Prodigy 20 points

    Hi Rogelio,

    Do you have an update on this issue?

    Best regards,

    Xiaoxian