[nRF Connect SDK](Urgent) How to fix Tx power?

[Tim Hwang]

Target nRF52832(nrf52dk_nrf52832)
SDK NCS v2.0.0
My project base: \nrf\samples\bluetooth\peripheral_hids_keyboard

Hello.
I want to increase Tx power for test. I already review sample(zephyr/samples/bluetooth/hci_pwr_ctrl) and I found it looks working in log.
I try to put changes into my project; however, it works at first time only.
I disconnect and connect again; I lose my pairing. I could connect again until BLE power off and on.
Can I fix my Tx power using CONFIX_XXX? Or how can fix it?

// main.c
static void set_tx_power(uint8_t handle_type, uint16_t handle, int8_t tx_pwr_lvl)
{
...
}

static void connected(struct bt_conn *conn, uint8_t err)
{
...
set_tx_power(BT_HCI_VS_LL_HANDLE_TYPE_CONN, default_conn_handle, 4);
}


Prj.conf
#Tx
CONFIG_BT_CTLR_ADVANCED_FEATURES=y
CONFIG_BT_CTLR_CONN_RSSI=y
CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y

[Einar Thorsrud]

Hi,

I am not sure I understand correctly, but is the problem that you are only able to set the Tx power for the first connection, but not subsequent ones? If so, my first thought is that you are using an invalid connection handle (for instance that you do not update it for subsequent connections). Could that be the case? If not, can you elaborate, explain what you have found by debugging (any error codes returned from bt_hci_cmd_send_sync() for instance?).

[Tim Hwang]

Thanks for updating.

1. CONFIG_XXX for Tx 
Do you have any idea?

2.. Handle
if(0==bt_hci_get_conn_handle(m_conn, &default_conn_handle))
{
set_tx_power(BT_HCI_VS_LL_HANDLE_TYPE_CONN, default_conn_handle, 4);
}
handle is correct.

log
00> update_txupdate_tx
00> set_tx_power (4)
00> Actual Tx Power: 4

[Tim Hwang]

Now I could fix my issue adding two configs, and clean build.
I could set Tx as 4.

#Tx
CONFIG_BT_CTLR_ADVANCED_FEATURES=y
CONFIG_BT_CTLR_CONN_RSSI=y
CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y

CONFIG_BT_LL_SOFTDEVICE=n
CONFIG_BT_LL_SW_SPLIT=y

[Einar Thorsrud]

Tim Hwang said:

1. CONFIG_XXX for Tx 
Do you have any idea?

You can change the default Tx power using CONFIG_BT_CTLR_TX_PWR_*, for instance CONFIG_BT_CTLR_TX_PWR_PLUS_4 to set +4 dBm. Note that this does not work with early versions of the SoftDevice controller, though.

Tim Hwang said:

2.. Handle

This code looks a bit odd, and while I did not fully understand the failure you described it is clear an error occurred). You should essentially do as you can see in the implementation of set_tx_power() in zephyr/samples/bluetooth/hci_pwr_ctrl/src/main.c. Note also that this is called with a parameter that distinguishes between roles).

[Einar Thorsrud]

Hi,

Ah, I did not notice that you posted this. Note that with this you are using the Zephyr LL instead of the SoftDevice Controller. That is OK and up to you, but I would normally recomend using the SoftDevice controller. This is also the controller we qualify (see Bluetooth QDIDs).