Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

p143 — Mon, 29 Apr 2019 19:11:35 GMT

That's OK Andreas. In fact, I was asking because I wanted to make sure that my app was using S=8 coding.

Best regards.

Juan

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Mon, 29 Apr 2019 12:54:22 GMT

Hi again Juan.

I think I might have explained badly in my previous replies.

It is correct that the Bluetooth Spec says this.

But, the SoftDevice is limited to only having the CI-field set to S=8 on the transmitted frame. There is nothing to due about this unfortunately.

Best regards,

Andreas

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

p143 — Fri, 26 Apr 2019 13:31:30 GMT

Hi.

Sure I'm wrong, but that's not what the Bluetooth Specification seems to say:

Best Regards,

Juan

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Fri, 26 Apr 2019 11:41:51 GMT

Hi.

On the transmitter side you only have the option of 125 kbps (S=8), you don't have to do anything.

Best regards,

Andreas

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

p143 — Fri, 26 Apr 2019 11:07:34 GMT

Hi.

I never said you set CI in the receiver side, Andreas. Anyway, my question was: How do you set the CI field to S=2 or S=8 on the transmitter side?

Best regards

Juan

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Fri, 26 Apr 2019 07:23:35 GMT

Hi.

It is correct that if FEC1 is S=8 and FEC2 is S=2, it will not make any sence.

But as I said in my previous reply, in the HW implementation for FEC2 we decode FEC2 in regards to what is set in CI.

If CI is S=8 then FEC2 is decoded as S=8, if CI is S=2 then FEC2 is decoded as S=2.

This is at the RX side, you don't "set" the CI field here.

Best regards,

Andreas

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

p143 — Thu, 25 Apr 2019 23:16:36 GMT

Hi Andreas.

Then If I got you right, when you want your extended advertising to benefit from the BT5 4xRange advantage (according to page 2565 on the BT Specification Version 5.0-Vol 6, Part B), you must set the Coding Indicator (CI Field on the FEC block 1 of the transmitted LE CODE PHY packet) to force S=8 coding over the FEC block 2. Otherwise, when you are working at 4xRange, you may receive the FEC block 1 but certainly not FEC block 2, since it will reach the receiver with only two symbols per bit coding and the receiver error correction scheme won't be able to compensate the noise at this range. Am I right? and if I am, how can you set this CI Field value to either S=2 or S=8?

Thanks and,

Best Regards

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Thu, 25 Apr 2019 06:03:38 GMT

Hi.

The header of Coded packets is always transmitted on S=8 (125 kbps), in the header there is a bit saying if the rest of the payload packet is S=8 or S=2 (500 kbps). Both decoding schemes are supported at the same time in the HW.

Best regards,

Andreas

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

p143 — Tue, 23 Apr 2019 15:17:04 GMT

Hi Andreas.

You said to Louis: "SoftDevice 6.1.0 is able to receive at 125 kbps and 500 kbps. But it can only transmit at 125 kbps" and also changing to ".scan_phys = BLE_GAP_PHY_CODED," in the scanner. But then, how the scanner knows whether to decode the received PDUs at 125 Kbps or 500 Kbps?

Thanks

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

Louis Wnag — Tue, 30 Oct 2018 09:54:46 GMT

Hi Andreas

Deeply appreciated.

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Thu, 25 Oct 2018 12:38:22 GMT

Hi.

In SDK 14.1 in nRF5_SDK_14.1.0\examples\ble_central\ble_app_blinky_c\main.c, this is defined on line 386 and 387.

ble_gap_phys_t const phys =
{
    .rx_phys = BLE_GAP_PHY_AUTO,
    .tx_phys = BLE_GAP_PHY_AUTO,
};

Change this to this:

ble_gap_phys_t const phys =
{
    .rx_phys = BLE_GAP_PHY_CODED,
    .tx_phys = BLE_GAP_PHY_CODED,
};

- Andreas

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

Louis Wnag — Thu, 25 Oct 2018 12:01:17 GMT

Hi Andreas

Deeply appreciated.

Very clear.

nRF5_SDK_14.1.0\examples\ble_central\ble_app_blink_c\main.c

Does not has ".scan_phys" to set BLE_GAP_PHY_CODED ? Am I right ?

static ble_gap_scan_params_t const m_scan_params =
{
.active = 0x1,
.interval = SCAN_INTERVAL,
.window = SCAN_WINDOW,
.timeout = SCAN_TIMEOUT,
#if (NRF_SD_BLE_API_VERSION <= 2)
.selective = 0,
.p_whitelist = NULL,
#endif
#if (NRF_SD_BLE_API_VERSION >= 3)
.use_whitelist = 0,
#endif
};

Best regards

Louis

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Thu, 25 Oct 2018 11:37:40 GMT

Hi Louis.

SoftDevice 6.1.0 is able to receive at 125 kbps and 500 kbps. But it can only transmit at 125 kbps.

These rates are fixed, you only have to set your scanning or advertising phys to BLE_GAP_PHY_CODED,

Like this in nRF5_SDK_15.2.0_9412b96\examples\ble_peripheral\ble_app_blinky\main.c :

Line 256:
adv_params.primary_phy     = BLE_GAP_PHY_1MBPS;

Change this line to:

adv_params.primary_phy     = BLE_GAP_PHY_CODED;

For scanning, you should for example in nRF5_SDK_15.2.0_9412b96\examples\ble_central\ble_app_gatts\, edit scan_phys in m_scan_param in main.c

FROM THIS:

/**< Scan parameters requested for scanning and connection. */
static ble_gap_scan_params_t const m_scan_param =
{
    .active        = 0x01,
    .interval      = NRF_BLE_SCAN_SCAN_INTERVAL,
    .window        = NRF_BLE_SCAN_SCAN_WINDOW,
    .filter_policy = BLE_GAP_SCAN_FP_WHITELIST,
    .timeout       = SCAN_DURATION_WITELIST,
    .scan_phys     = BLE_GAP_PHY_1MBPS,
};

TO THIS:

/**< Scan parameters requested for scanning and connection. */
static ble_gap_scan_params_t const m_scan_param =
{
    .active        = 0x01,
    .interval      = NRF_BLE_SCAN_SCAN_INTERVAL,
    .window        = NRF_BLE_SCAN_SCAN_WINDOW,
    .filter_policy = BLE_GAP_SCAN_FP_WHITELIST,
    .timeout       = SCAN_DURATION_WITELIST,
    .scan_phys     = BLE_GAP_PHY_CODED,
};

- Andreas

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

Louis Wnag — Thu, 25 Oct 2018 11:07:51 GMT

Hi Andreas

Thanks your quick response.

In SDK 15.2 with SoftDevice 6.1.0: BLE_GAP_PHY_CODED

is receive and transmit at 125 kbps.

is only receive at 500 kbps ?

Is able to set fixed rate at 125 or 500 kbps ?

Best regards

Louis

RE: Nordic52840 --- How to fixed PHY rate at 500 and 125 Kbps.

AndreasF — Thu, 25 Oct 2018 10:37:59 GMT

Hi Louis.

In SDK 14.1 which uses SoftDevice 5.0.0-2.alpha, you can only receive and transmit at 125 kbps.

I recommend that you use SDK 15.2, as this is our newest SDK with most features and fewest bugs.

In SDK 15.2, you can use the latest release of the SoftDevice (version 6.1.0), which lets you either receive at 500 kbps, and transmit and receive at 125 kbps.

You can read more about this in the BLE 5.0 specification, at page 2565.

So, to sum up:

In SDK 14.1 with SoftDevice 5.0.0-2.alpha:

BLE_GAP_PHY_CODED is receive and transmit at 125 kbps

In SDK 15.2 with SoftDevice 6.1.0:

BLE_GAP_PHY_CODED is receive and transmit at 125 kbps, and receive at 500 kbps

- Andreas