set tx power with tx power service on zephyr

RE: set tx power with tx power service on zephyr

ziv123 — Wed, 02 Feb 2022 10:19:40 GMT

i will open a new thread on the ncs update (wish i would have done that 10 days ago)

currently the 'set_tx_power()' does not work for me but i moved to work on something else for the moment .. once the issue will be solved i will close this thread with the solution

best regards

Ziv

RE: set tx power with tx power service on zephyr

Jørgen Holmefjord — Tue, 01 Feb 2022 14:30:40 GMT

Hi,

[quote user="ziv123"]

seems that moving to ncs 1.8 forces me to update to zephyr-sdk-0.13.2 (from 0.12.4)

is it really a must or am i missing something ?

[/quote]

I'm not sure about this, I'm running Windows, so the Zephyr SDK is not available for my platform. What is forcing you to do this updat?

[quote user="ziv123"]

also, seems that when moving to the new zephyr sdk i have a problem with the dfu (based on the smp service), i use the nrfConnect for the dfu and it seems like its done ok but then after reset the version remains the old version. any ideas on why is that, maybe i need to change some configs ?

do i also need to update the MCUBoot or/and the bootloader version for this to work ?

[/quote]

I would recommend you to post this issue in a new ticket, as it is off topic for this thread. That way, you will also get help from someone more knowledgeable about this topic than me.

Best regards,
Jørgen

RE: set tx power with tx power service on zephyr

ziv123 — Sun, 23 Jan 2022 07:33:34 GMT

seems that moving to ncs 1.8 forces me to update to zephyr-sdk-0.13.2 (from 0.12.4)

is it really a must or am i missing something ?

do i also need to update the MCUBoot or/and the bootloader version for this to work ?

hope to read from you soon

best regards

Ziv

RE: set tx power with tx power service on zephyr

John — Fri, 21 Jan 2022 23:17:28 GMT

When you start using SDK V18, I've learned that you need to create the advertising packet before you are allowed to change the power.

RE: set tx power with tx power service on zephyr

Jørgen Holmefjord — Tue, 18 Jan 2022 18:19:50 GMT

Hi,

0xFC0E is the opcode of BT_HCI_OP_VS_WRITE_TX_POWER_LEVEL. As you can see from the HCI VS API, this is defined as ((0x000E) | ((0x3F) << 10)) = 0xFC0E. As far as I can see, status code 0x42 means BT_HCI_ERR_UNKNOWN_ADV_IDENTIFIER.

I tested you code and configs together with the peripheral_lbs example in NCS v1.8.0, and the TX power seems to be changed correctly with the latest addition (actually only "CONFIG_BT_LL_SW_SPLIT=y" is need in my test). Verified that the RSSI is significantly lower with TX output power set to -40 through set_tx_power().

It looks like you are using an older version, can you try with NCS v1.8.0?

Best regards,
Jørgen

RE: set tx power with tx power service on zephyr

ziv123 — Sat, 15 Jan 2022 09:55:25 GMT

hi Jorgen

is this on research or something ?

i have posted a replay more the 5 days ago, re-posted an edited the replay 3 days ago and no replay

hope to read from you soon

best regards

Ziv

RE: set tx power with tx power service on zephyr

ziv123 — Wed, 12 Jan 2022 19:05:27 GMT

hi Jorgen

i am using "Zephyr version: 2.6.99 (/home..), build: v2.6.99-ncs1-1

i tried to use the implementation of the set_tx_power from the hci_pwr_ctrl example in my code

{
    struct bt_hci_cp_vs_write_tx_power_level *cp;
	struct bt_hci_rp_vs_write_tx_power_level *rp;
	struct net_buf *buf, *rsp = NULL;
	int err;

    buf = bt_hci_cmd_create(BT_HCI_OP_VS_WRITE_TX_POWER_LEVEL, sizeof(*cp));
    if (!buf) 
    {
		LOG_ERR("Unable to allocate command buffer %d", 0);
		return;
	}
    LOG_INF("in TX_POWER INIT BUFFER CREATED %d", 0);
	cp = net_buf_add(buf, sizeof(*cp));
	cp->handle = sys_cpu_to_le16(0);
	cp->handle_type = BT_HCI_VS_LL_HANDLE_TYPE_ADV;
    cp->tx_power_level = 4;

    err = bt_hci_cmd_send_sync(BT_HCI_OP_VS_WRITE_TX_POWER_LEVEL, buf, &rsp);
    
    if (err) {
		uint8_t reason = rsp ?
			((struct bt_hci_rp_vs_write_tx_power_level *)
			  rsp->data)->status : 0;
		LOG_ERR("Set Tx power err: %d reason 0x%02x\n", err, reason);
		return;
	}

	rp = (void *)rsp->data;
	LOG_INF("Actual Tx Power: %d\n", rp->selected_tx_power);

    net_buf_unref(rsp);
}

my prf.conf:

# BLE Related Configs
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="TX_PWR_Canary"
CONFIG_BT_DEVICE_NAME_DYNAMIC=y
CONFIG_BT_DIS=y
CONFIG_BT_DIS_PNP=n
CONFIG_BT_DIS_MODEL="Canary"
CONFIG_BT_DIS_MANUF="Augury Inc."
CONFIG_BT_DIS_SERIAL_NUMBER=y
CONFIG_BT_DIS_FW_REV=y
CONFIG_BT_DIS_HW_REV=y
CONFIG_BT_DIS_SW_REV=n
CONFIG_BT_CTLR_ADVANCED_FEATURES=y
CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y
CONFIG_BT_CTLR_TX_PWR_MINUS_20=y

# Below is setup to let DIS information be read from settings
CONFIG_SETTINGS_RUNTIME=y
CONFIG_SETTINGS=y
CONFIG_SETTINGS_NONE=y
CONFIG_BT_SETTINGS=y
CONFIG_BT_DIS_SETTINGS=y
CONFIG_BT_DIS_STR_MAX=50
CONFIG_BT_GATT_CACHING=n
CONFIG_BT_HCI_VS_EXT=y


# Some command handlers require a large stack.
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

strangely i got an error that i could not find in the my ncs directory

"<wrn> bt_hci_core: opcode 0xfc0e status 0x42" what does this error mean, (also why the use of opcode 0xFC0E which is not if i understand for production tests) ?

and the "bt_hci_cmd_send_sync(..) returns err num -5, with reason 0x00

if i add the following to my prj.conf:

CONFIG_MAIN_STACK_SIZE=2048
CONFIG_BT_LL_SOFTDEVICE=n
CONFIG_BT_LL_SW_SPLIT=y

then i get success from the function but in fact the tx_power does not change at all, not in advertising and not in connection

would be happy to understand what does the stack size and the sw split configs contribute, and also what am i missing or doing wrong that prevent the change to the tx power (stays on default '0' all the time)

also i wonder why setting CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y, in the prj.conf, prevent using the effect of CONFIG_BT_CTLR_TX_PWR_MINUS_20=y, for example ?

hope to read from you soon, i actually re-edit and re-entered my replay since i did not see any message indication that my replay was received and.. i hope i get some now

best regards

Ziv

RE: set tx power with tx power service on zephyr

Jørgen Holmefjord — Thu, 06 Jan 2022 15:51:00 GMT

Hi,

[quote user="ziv123"]i saw there is an example in zephyr/samples/bluetooth/hci_pwr_ctrl , i wanted to make sure i understand it right then .. is it just for the nrf52840 peripheral side and it is actually not showing how to set the tx power from a central side, after connection has been established and the nrf52840 peripheral is configured to by it self try save on tx power via the analysing of the RSSI ?[/quote]

Yes, that is correct.

[quote user="ziv123"]is it actually possible to change the tx power within an already established ble connection via some custom service[/quote]

Yes, you you create a custom service, you can change the TX power when the set TX power characteristics is written, just like the sample changes the power dynamically based on RSSI.

[quote user="ziv123"]is there some service that already contain this feature?[/quote]

I'm not aware of any such service, but you can follow "nRF Connect SDK Bluetooth Low Energy tutorial part 1: Custom Service in Peripheral role" to create your own custom service in nRF Connect SDK.

Best regards,
Jørgen

RE: set tx power with tx power service on zephyr

ziv123 — Thu, 06 Jan 2022 10:25:12 GMT

Hi Jorgen

i saw there is an example in zephyr/samples/bluetooth/hci_pwr_ctrl , i wanted to make sure i understand it right then .. is it just for the nrf52840 peripheral side and it is actually not showing how to set the tx power from a central side, after connection has been established and the nrf52840 peripheral is configured to by it self try save on tx power via the analysing of the RSSI ?

is it actually possible to change the tx power within an already established ble connection via some custom service (is there some service that already contain this feature? ) ?

hope to read from you soon

best regards

Ziv

RE: set tx power with tx power service on zephyr

Jørgen Holmefjord — Wed, 05 Jan 2022 09:47:23 GMT

Hi,

The Tx Power Service (TPS) is a Bluetooth defined service, you can find the specification on this page. If you look at chapter 3 of the specification, you can see that only Read property is mandatory, while other properties are marked ‘X’ (excluded/not permitted).

If you want to set the TX power, you need to create a custom service for this.

Best regards,
Jørgen