where is the source code to enter dtm?

[panpgg]

Hi,

    From https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/direct_test_mode/README.html, it writes "After programming the sample to your development kit, you can test it in three ways.....". It means after programming image to dk, I can test dtm directly.

    But I traced source code, I can't find where to enter dtm. The flow of code:

- dtm_init() :  clock_init() -> timer_init() -> gppi_init() -> radio_init()

- dtm_uart_wait_init()

- dtm_tr_get() : wait user input two bytes data

I don't know where is the step to enter dtm. Could you tell me what device do to enter dtm and where is the specific code?

Thank you.

    

[Susheel Nuguru]

he device does not enter DTM by itself; instead, it initializes the DTM functionality and waits for external input. it is triggered by sending specific commands over UART to the device.

[panpgg]

Hi ,

    Thank you for your replay. I know device does not enter DTM by itself, that's why I want to know the answer.

From your reply what's the specfic commands to let device enter dtm? It should not defined by  Bluetooth^® Core Specification (Vol. 6, Part F).

And the detail of commands do?(like writing regsters or others)

plz tell me whre is the source code and I can trace it.

Thank you.

[Susheel Nuguru]

The dtm_init only prepares the hardware in a listening mode and the dtm_tr_get waits for the command from the tester (which you already know) then the received DTM command is processed in dtm_tr_process and then the command is sent to the BLE controller using the underlying transport (HCI or serial based on selected configs) in the function hci_cmd().

If you go for example in dtm_hci.c file and look into hci_cmd->hci_reset->dtm_setup_reset-> radio_init 

In the above sequence you can see that you application responding to the radio reset command and requesting this to the hci and in radio_init, the radio registers are actually reset to default.