Distinguish between Coded S2 and S8 (NRF52840)

RE: Distinguish between Coded S2 and S8 (NRF52840)

Simonr — Fri, 30 Aug 2024 05:35:06 GMT

Hi Fabio

This config only enables support for the Bluetooth 5.0 Coded PHY in the controller. You still need to enable it in the application. Here it seems like you're setting the preferred PHY in the connection parameters, but the device likely still advertises in 1MBPS PHY. I'd recommend checking out the peripheral_hr_coded sample available here.

Best regards,

Simon

RE: Distinguish between Coded S2 and S8 (NRF52840)

STE — Thu, 29 Aug 2024 14:23:28 GMT

I'm try same exercise to test different Coded PHY, but settings as below into the update_phy function:

	const struct bt_conn_le_phy_param preferred_phy = {
		.options = BT_CONN_LE_PHY_OPT_CODED_S8,
		.pref_rx_phy = BT_GAP_LE_PHY_CODED,
		.pref_tx_phy = BT_GAP_LE_PHY_CODED,
	};
	err = bt_conn_le_phy_update(conn, &preferred_phy);
	if (err) {
		LOG_ERR("bt_conn_le_phy_update() returned %d", err);
	}

also I've enabled the Kconfig

CONFIG_BT_CTLR_PHY_CODED=y

into the prj.conf file but the log always write PHY updated. New PHY: 1M.

Also by nRF Connect App (Android) it give in Log view PHY = LE 1M.

How to be sure about the mode?

Thanks and best regards.

Fabio

RE: Distinguish between Coded S2 and S8 (NRF52840)

Simonr — Mon, 29 Jan 2024 11:40:56 GMT

So, after looking at this it seems you're reading the incorrect defines here. struct bt_conn_le_phy_info only provides uint8_t tx_phy and uint8_t rx_phy and only correspond to 1MBPS PHY, 2MBPS PHY and CODED PHY, so you should look at these instead of the BT_CONN_LE_PHY_OPT_CODED parameters.

/** All LE PHYs. */
#define BT_CONN_LE_PHY_PARAM_ALL BT_CONN_LE_PHY_PARAM(BT_GAP_LE_PHY_1M |   \
						      BT_GAP_LE_PHY_2M |   \
						      BT_GAP_LE_PHY_CODED, \
						      BT_GAP_LE_PHY_1M |   \
						      BT_GAP_LE_PHY_2M |   \
						      BT_GAP_LE_PHY_CODED)

By hovering BT_GAP_LE_PHY_CODED you can see that it also returns 4 if in use:

I think you're running in the option you're setting, but you will need to check the option's return code specifically to make sure. Or connect with the nRF Connect app for Android/iOS and see what PHY is used there.

Best regards,

Simon

RE: Distinguish between Coded S2 and S8 (NRF52840)

Phobios — Fri, 26 Jan 2024 16:01:22 GMT

I'm using the NRF Connect SDK with version v2.4.2 and the SoftDevice Controller.

I've tested the peripheral_hr_coded examples now and there the coded connection is used with value 4
(Connected: D9:E5:ED:BF:7E:69 (random), tx_phy 4, rx_phy 4)

Does value 4 now mean S2 or S8? Or in a simpler question. How can I set the coded PHY to S8 in user code?

Best Regards,

Manuel

RE: Distinguish between Coded S2 and S8 (NRF52840)

Simonr — Fri, 26 Jan 2024 12:11:04 GMT

I can't recall seeing this issue on I.E. the Peripheral Heart Rate Monitor with Coded PHY sample, so can you provide some more details on what exactly you're doing? https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.1/nrf/samples/bluetooth/peripheral_hr_coded/README.html

What SDK version and what Bluetooth controller are you using exactly, the SoftDevice Controller or Zephyr Controller? Then I can confirm this on my end and potentially report it internally.

The easiest way to distinguish S2 and S8 in a measurable way would be with throughput I think, as S2 should be able to run up to 500kbps, while S8 is only able run up to 125kbps.

Best regards,

Simon