ble stack softdevice vs ncs dbm/rssi/range wise

RE: ble stack softdevice vs ncs dbm/rssi/range wise

ziv123 — Tue, 14 Mar 2023 10:44:38 GMT

hi Edvin

yes i thought about the 'CONFIG_BT_CTLR_TX_PWR_PLUS_4' later on and actually on the ncs code base we used PLUS_8 cause its a common code base for several boards now but on the SDK code it was set to 4 tx_power

so i added it in the .conf file of each board after i checked what was in the .config file .. and since nrf52832 apparently does not support tx_power 8, then it defaulted to zero i guess (the other board runs with nrf52840).

i haven't replayed yet since i wanted to do some checking and see if it explains the difference i saw. and it seems like it does

thanks :)

RE: ble stack softdevice vs ncs dbm/rssi/range wise

Edvin — Tue, 14 Mar 2023 10:32:01 GMT

Hello,

An update. I was playing around with this, and I found that the NCS\zephyr\samples\bluetooth\hci_pwr_ctrl checks the TX power for a certain connection (as it is possible to set them for every connection). Check out that sample. It will fetch the TX power when it connects and print it to the log. I took the liberty to add this to the peripheral_uart sample as well. You just need to add the following configurations to prj.conf:

CONFIG_BT_CTLR_TX_PWR_PLUS_4=y
CONFIG_BT_CTLR_CONN_RSSI=y
CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y

And check out the following main.c file:

devzone.nordicsemi.com/.../813862.main.c

Best regards,

Edvin

RE: ble stack softdevice vs ncs dbm/rssi/range wise

Edvin — Mon, 13 Mar 2023 14:05:46 GMT

Hello,

If you program the board with each of the applications (from the nRF5 SDK and NCS), and start the application, and then try to read out the TX power register manually using:

nrfjprog --memrd 0x4000150c

What is the value of that register in case of the nRF5 SDK and the NCS application?

Best regards,

Edvin

RE: ble stack softdevice vs ncs dbm/rssi/range wise

ziv123 — Sat, 11 Mar 2023 15:00:35 GMT

[quote userid="2125" url="~/f/nordic-q-a/97458/ble-stack-softdevice-vs-ncs-dbm-rssi-range-wise/414657"]Swap FW back and forth a we times to see if it's consistent with the version[/quote]

it is consistent, it was on sdk for a long time and readings were constant, moved to ncs and a different reading is now constant

[quote userid="2125" url="~/f/nordic-q-a/97458/ble-stack-softdevice-vs-ncs-dbm-rssi-range-wise/414657"]check the output power settings for both and make sure they are the same.[/quote]

how do i check the output power settings, which config or something else in sdk and in ncs ?

RE: ble stack softdevice vs ncs dbm/rssi/range wise

ketiljo — Fri, 10 Mar 2023 13:37:07 GMT

Swap FW back and forth a we times to see if it's consistent with the version. If it is, check the output power settings for both and make sure they are the same.

RE: ble stack softdevice vs ncs dbm/rssi/range wise

ziv123 — Thu, 09 Mar 2023 14:49:26 GMT

[quote userid="2125" url="~/f/nordic-q-a/97458/ble-stack-softdevice-vs-ncs-dbm-rssi-range-wise/414412"]small differences in placement of the transmitter will often have great effect on the RSSI in the other end. [/quote]

what do you mean by small differences ? , i am seeing difference for the same board at the same place with same transmitter. the only thing that change is the FW which was bare metal SDK 11.0 as mentioned and is now ncs 2.1.0

RE: ble stack softdevice vs ncs dbm/rssi/range wise

ketiljo — Thu, 09 Mar 2023 14:35:18 GMT

Unless you have set different output power, there are no difference between the stacks when it comes to output power. RSSI isn't the best way to evaluate the output power as small differences in placement of the transmitter will often have great effect on the RSSI in the other end.