HCI_UART sample， Enabling DTM cannot configure tx power through hci command

[Ethan.Shi]

Hi

   Based on NCS 2.3.0，I started by referencing this link and compiling it using the relevant configuration How to setting TX power through HCI command? - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)，

Add the below setting on "prj.conf" and re-build the project.

CONFIG_BT_HCI_VS=y

CONFIG_BT_HCI_VS_EXT=y

CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y

CONFIG_BT_HCI_RAW_CMD_EXT=y

CONFIG_BT_CTLR_SET_HOST_FEATURE=y

Run command: hcitool -i hci0 cmd 0x3f 0x000e 0x00 0x00 0x00 -8, set TX power Success

Execute the following command and btmon results：

hcitool cmd 0x08 0x0007
< HCI Command: ogf 0x08, ocf 0x0007, plen 0
> HCI Event: 0x0e plen 5
  01 07 20 00 F8
  
btmon
@ RAW Open: hcitool (privileged) version 2.22                                                                                                                           {0x0004} [hci0] 6.431766
< HCI Command: LE Read Advertising Channel TX Power (0x08|0x0007) plen 0                                                                                                      #1 [hci0] 6.434787
> HCI Event: Command Complete (0x0e) plen 5                                                                                                                                   #2 [hci0] 6.440189
      LE Read Advertising Channel TX Power (0x08|0x0007) ncmd 1
        Status: Success (0x00)
        TX power: -8 dbm (0xfffffff8)
@ RAW Close: hcitool   

To conduct Direct Test Mode (DTM) HCI testing, add configuration：

CONFIG_BT_LL_SW_SPLIT=y

CONFIG_BT_LLL_VENDOR_NORDIC=y

rebuild

Run command: hcitool -i hci0 cmd 0x3f 0x000e 0x00 0x00 0x00 -8, set TX power Success

Execute the following command and btmon results：

hcitool cmd 0x08 0x0007 
< HCI Command: ogf 0x08, ocf 0x0007, plen 0
> HCI Event: 0x0e plen 5
  01 07 20 00 00
  
  

btmon
@ RAW Open: hcitool (privileged) version 2.22                                                                                                                           {0x0003} [hci0] 6.625427
< HCI Command: LE Read Advertising Channel TX Power (0x08|0x0007) plen 0                                                                                                      #1 [hci0] 6.625593
> HCI Event: Command Complete (0x0e) plen 5                                                                                                                                   #2 [hci0] 6.630707
      LE Read Advertising Channel TX Power (0x08|0x0007) ncmd 1
        Status: Success (0x00)
        TX power: 0 dbm (0x00)
@ RAW Close: hcitool

After adding DTM related configurations, the command to set TX power did not take effect. I would like to know the reason and if there is a way to perform DTM testing and set TX power simultaneously

Thanks

[Hung Bui]

Hi Shi, 

When setting CONFIG_BT_LL_SW_SPLIT=y you are choosing to use Zephyr controller  instead of Nordic controller. Could you explain ? 
Could you point me to where you find information about the configuration needed for DTM ? 

[Ethan.Shi]

Hi

By link Does Zephyr support DTM test directly? - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)，Using DTM testing requires configuration ，CONFIG_BT_CTLR_DTM_HCI=y，HCI_UART example defaults to this configuration

After compiling, I found that

I am in \v2.3.0\zephyr\subsys\bluetooth\controller\Kconfig.dtm and \v2.3.0\zephyr\subsys\bluetooth\controller\Kconfig.ll_sw_split， The relevant configuration was found in the file。

I have set the relevant configuration and the DTM command was successful

CONFIG_BT_LL_SW_SPLIT=y

CONFIG_BT_LLL_VENDOR_NORDIC=y

DTM command：hcitool cmd 0x08 0x001e 0x13 0x25 0x00

[Hung Bui]

Hi Shi, 
Thanks for the info. 
My understanding is that the Nordic controller doesn't support DTM directly on the controller. 
You would need to use DTM sample to do Direct test. 

The reason tx power can not be configured when you do DTM direct on the controller is most likely you were using the vendor specific HCI command to control TX Power that only works on Nordic Controller not the Zephyr controller. 

But my understanding is that you can set the TX Power with the DTM command, you don't need to set it using the HCI command. I'm looking at the dtm_set_txpower() in the dtm sample.