Can't get BLE device to sleep

RE: Can't get BLE device to sleep

Simonr — Wed, 23 Oct 2024 13:19:03 GMT

Glad to hear you figured it out!

Some closing remarks from our side.

1. Yes, using the SYNTH for the LF clock source will cause the HF crystal to always be on and thus the device will never be in a low power state as is possible with the other clock sources.

Best of luck in future endeavors!

-Simon

RE: Can't get BLE device to sleep

prsboy — Tue, 22 Oct 2024 17:44:28 GMT

Simonr Edvin

It's taken a long time, but I finally got myself hold of a PPK2 and the measurements are looking much more reasonable:

I think I can finally mark this as solved. I think to sum up the problems faced:

1. My setting of SYNTH for the clock LFCLK. This caused the device never to sleep.

2. The reason I needed SYNTH was that there was a hardware issue within the PCB design effecting the antenna which caused BLE not to be detectable using anything other than a configuration that caused the device to not be able to sleep (or otherwise be undetectable).

3. Once 2. was resolved, I could set LFCLK to RC Oscillator and use the recommended settings for the LFCLK

#define CLOCK_CONFIG_LF_SRC 0
#define NRFX_CLOCK_CONFIG_LF_SRC 0
#define NRF_SDH_CLOCK_LF_SRC 0
#define NRF_SDH_CLOCK_LF_RC_CTIV 16
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
#define NRF_SDH_CLOCK_LF_ACCURACY 1

4. The PPK1 was giving unreliable readings for power measurement meaning that the readings were showing some clearly erroneous results. Purchasing a PPK2 to test helped show the correct power reading, which averages:

~4.55uA

Thank you for your patience with this - it's been quite an puzzle on my side. Thanks for baring with me during it, I really appreciate the support, it's been top quality.

RE: Can't get BLE device to sleep

Simonr — Wed, 24 Jul 2024 08:16:28 GMT

Hi Nathan

80mA is more than the nRF52 series devices are able to draw altogether I think, so this current consumption measurement can't be correct I'm afraid, so please double check how the Power Profiler Kit is set up to measure the current here. Usually when seeing this number from a PPK, you also see the current consumption from the connected J-Link debugger chip onboard the connected DK for some reason.

I'd recommend using a PPK2 if you have available as it is notably easier to use and more accurate too.

Best regards,

Simon

RE: Can't get BLE device to sleep

prsboy — Mon, 22 Jul 2024 13:12:40 GMT

Hey Simon!

The only issue remaining is posted here and it's drawing 80mA, not 400uA. This number seems wildly high for the radio/BLE cycle.

The sleep cycle is fine, it draws the correct/expected current.

Nathan

RE: Can't get BLE device to sleep

Simonr — Mon, 22 Jul 2024 13:09:21 GMT

I'm taking over this case until Edvin is back now, and from reading it seems you're on a good path now. Just to confirm, the issue remaining is that you're seeing a ~400µA current draw "extra" when enabling the radio/BLE, correct? If so, that's likely the HF crystal drawing this current, as that will draw ~400µA when running, and is required to run for the radio peripheral to work, and this will be expected. Let me know if I'm misunderstanding something with your issue here.

Best regards,

Simon

RE: Can't get BLE device to sleep

Maria Gilje — Fri, 19 Jul 2024 10:58:25 GMT

Hello,

Thank you for sharing your progress and good news.

[quote user="prsboy"]so I guess the only remaining thing is to work out the high power consumption when in bluetooth advertisement [/quote]

One of my colleagues will support you with this when they are back in office next week. Thank you for your patience.

Best regards,

Maria

RE: Can't get BLE device to sleep

prsboy — Tue, 16 Jul 2024 18:16:31 GMT

Yep, this is exactly how i've got it setup, I re-ran the test again today and got the same results.

i'm going to start removing stuff from the program and see if i can identify what's causing this "active"state to be 80mA.

The good news is:

After going back to the hardware it seemed like the original problem was around the antenna. It seems like the incorrect antenna setup was causing the device to need more power (i'm guessing) for me to be able to receive a signal (perhaps why SYNTH worked fine best?).

I have had a new set of prototype devices manufactured and I have set the device up as recommended

#define CLOCK_CONFIG_LF_SRC 0
#define NRF_SDH_CLOCK_LF_SRC 0
#define NRF_SDH_CLOCK_LF_RC_CTIV 16
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
#define NRF_SDH_CLOCK_LF_ACCURACY 1

and the device now is advertising perfectly clearly:

and now with the correct/recommended LF clock settings, we can see the sleep cycle is an actual sleep cycle:

so I guess the only remaining thing is to work out the high power consumption when in bluetooth advertisement

RE: Can't get BLE device to sleep

Edvin — Mon, 24 Jun 2024 12:10:40 GMT

Is this how you connected your custom HW?
https://infocenter.nordicsemi.com/topic/ug_ppk/UG/ppk/PPK_user_guide_PPK_on_customHW_with_nRF5xDK.html?cp=11_10_5_4

If so, which one of the figures did you follow? And did you make sure that all the switches are set in the position that are noted in the figures?

I agree, your numbers seems a bit too high.

BR,

Edvin

RE: Can't get BLE device to sleep

prsboy — Sat, 22 Jun 2024 00:15:33 GMT

hello again Edvin !

After a few attempts at trying to get the PPK1 to work, I managed to take some readings. This is with the previously mentioned configuration:

#define CLOCK_CONFIG_LF_SRC 0
#define NRF_SDH_CLOCK_LF_SRC 0
#define NRF_SDH_CLOCK_LF_RC_CTIV 1
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 0
#define NRF_SDH_CLOCK_LF_ACCURACY 9

with 10 seconds advertising, then 120 seconds sleep. This is the graph for one sleep/wake cycle

here is 1 seconds worth of data for the awake period

and here is 1 second for the sleep period

this all seems very high to me, so perhaps i've not setup the device correctly. here's how i have it setup:

1. I have plugged the PPK1 into the DK.

2. I have plugged in the computer to the DK.

3. I have used the EXTERNAL OUT pins on the PPK1 to provide power to my custom PCBA

does that make sense? if not, I can take a photo.

RE: Can't get BLE device to sleep

Edvin — Fri, 10 May 2024 07:41:29 GMT

[quote user="prsboy"]

Will a PPK1 do? I can get ahold of one of those in a few days.

[/quote]

Yes. That works too. The PPK2 is a bit easier to use, but the PPK 1 will still give accurate readings, and perhaps show some patterns that can reveal something.

[quote user="prsboy"]How do I request a specific hardware review?[/quote]

Just create a ticket here on DevZone (but make it private, unless you want your design to be out in the public), and add your PCB layout files and your schematics. If you didn't design the HW, then talk to the people who did, and they probably know what files we are talking about. And if something is missing, the HW engineer from our side that is assigned to the ticket will know what additional files to request.

However, before you do this. Did you test this on one device, or do you have several custom boards? It would be interesting to know whether this behavior is only present on one nRF Chip, or several.

BR,
Edvin

RE: Can't get BLE device to sleep

prsboy — Wed, 08 May 2024 18:34:11 GMT

Indeed, very strange.

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481926"]Do you happen to have a PPK2? If so, can you please capture some graphs from running on SYNTH, and from running the RC_OSCILLATOR? A multimeter doesn't really give a clear picture of what's going on.[/quote]

Will a PPK1 do? I can get ahold of one of those in a few days.

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481926"]Have you tried to capture a sniffer trace of the advertisements? You can do so using the nRF Sniffer for Bluetooth LE. If possible, can you upload one trace usnig SYNTH and one using the RC_OSCILLATOR?[/quote]

I will get those sniffer traces uploaded for both SYNTH and RC.

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481926"]If you have not already, I suggest that you also create a new ticket where you upload your schematics and PCB layout and ask for a layout review. I am not sure what it would be, but perhaps one of our HW engineers can spot something that I have not thought of. [/quote]

How do I request a specific hardware review?

RE: Can't get BLE device to sleep

Edvin — Mon, 06 May 2024 07:38:18 GMT

I find this very odd.

Do you happen to have a PPK2? If so, can you please capture some graphs from running on SYNTH, and from running the RC_OSCILLATOR? A multimeter doesn't really give a clear picture of what's going on.

If you have not already, I suggest that you also create a new ticket where you upload your schematics and PCB layout and ask for a layout review. I am not sure what it would be, but perhaps one of our HW engineers can spot something that I have not thought of.

Have you tried to capture a sniffer trace of the advertisements? You can do so using the nRF Sniffer for Bluetooth LE. If possible, can you upload one trace usnig SYNTH and one using the RC_OSCILLATOR?

BR,
Edvin

RE: Can't get BLE device to sleep

prsboy — Thu, 02 May 2024 18:22:23 GMT

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481435"]

Ok, that looks good. I can't tell from your snippet, but that is using the RC-oscillator, and not the SYNTH LFCLK_SRC, right?

[/quote]

Correct, with the RC oscillator.

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481435"]When you initially tested your own application, and the issue was the high current consumption. Were you able to pick up more advertising packets then? When you were using the SYNTH source for the LF clock? Or was the performance the same?[/quote]

Yes, when setting the LFCLK to SYNTH everything behaves exactly how I'd expect. I've attached two scans, the first one is my custom PCBA with SYNTH, the second is using the RC oscillator:

SYNTH

#define CLOCK_CONFIG_LF_SRC 2

#define NRF_SDH_CLOCK_LF_SRC 2

#define NRF_SDH_CLOCK_LF_RC_CTIV 0

#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 0

#define NRF_SDH_CLOCK_LF_ACCURACY 5

-----

#define ADV_TIMEOUT 1000
#define SLEEP_IN_MS 10000

As you can see from the screenshot, it's advertising for 10 seconds then sleeping for 10 seconds.

RC oscillator

#define CLOCK_CONFIG_LF_SRC 0

#define NRF_SDH_CLOCK_LF_SRC 0

#define NRF_SDH_CLOCK_LF_RC_CTIV 16

#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2

#define NRF_SDH_CLOCK_LF_ACCURACY 1

-----

#define ADV_TIMEOUT 1000
#define SLEEP_IN_MS 10000

just to add more intrigue into this, when running the RC oscillator, with the same configuration as above, nothing shows up.

If I update the advertising timeout to 20 seconds,

#define ADV_TIMEOUT 2000
#define SLEEP_IN_MS 10000

I get this:

Note the duration of this scan 38 minutes and it detected 35 advertisement packets. When I use the synthesised clock I get that in a few seconds.

Whilst this update frequency would be fine, the problem is when I then reduce the sleep to 120 seconds to preserve battery, it'll be a much longer period of time before an advertisement is picked up.

Edit:

I decided I was just going to play around with the rc configuration. The following configuration works* best for my device:

#define CLOCK_CONFIG_LF_SRC 0
#define NRF_SDH_CLOCK_LF_SRC 0
#define NRF_SDH_CLOCK_LF_RC_CTIV 1
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 0
#define NRF_SDH_CLOCK_LF_ACCURACY 9

With these values, and setting the original settings of 10 seconds advertising, 10 seconds sleep I get the following:

Now, it's nowhere near as good as using the synthesised lfclk, but at least i'm detecting multiple packets per advertisements each wake cycle.

* As with everything, there's a cost to this - the "sleep" cycle is almost non-existent as it hops from sleep into what I imagine is a wake calibrate the rc oscillator. This is the power being used whilst in sleep:

To my fairly uneducated mind, this configuration change and increase in packets received does suggest that the rc oscillator is not stable enough with the recommended settings - does that make sense?

RE: Can't get BLE device to sleep

Edvin — Thu, 02 May 2024 06:09:38 GMT

[quote user="prsboy"]and the output looks good to me[/quote]

Ok, that looks good. I can't tell from your snippet, but that is using the RC-oscillator, and not the SYNTH LFCLK_SRC, right?

Just so I didn't misunderstand something. When you initially tested your own application, and the issue was the high current consumption. Were you able to pick up more advertising packets then? When you were using the SYNTH source for the LF clock? Or was the performance the same?

RE: Can't get BLE device to sleep

prsboy — Tue, 30 Apr 2024 16:55:47 GMT

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481267"]Advertising every 5 seconds is pretty slow. I see that you tried experimenting with different advertising intervals. Have you tried running one of the simpler samples on your custom board? [/quote]

I misspoke when I said this, sorry. I meant timeout, not interval. So 5 seconds advertising (100ms interval) - sleep for 10 seconds - repeat.

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481267"]I noticed a warning when building your application again, that NRFX_RNG_ENABLED was defined more than once.[/quote]

I believe that to not be an issue, it's when I was setting up the crypto libraries. I believe it's when I define both

#define RNG_ENABLED 1

#define NRFX_RNG_ENABLED 1

They're the same thing?

That being said, here is the output of the application you requested:

<info> app: NRFX_RNG_ENABLED 1
<info> app: CLOCK_CONFIG_LF_SRC 0
<info> app: NRF_SDH_CLOCK_LF_SRC 0
<info> app: NRF_SDH_CLOCK_LF_RC_CTIV 16
<info> app: NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
<info> app: NRF_SDH_CLOCK_LF_ACCURACY 1
<info> app: checking LFCLK ...
<info> app: LFCLK started!
<info> app_timer: RTC: initialized.
<info> CLOCK: Function: nrfx_clock_init, error code: NRF_SUCCESS.
<info> clock: Function: nrf_drv_clock_init, error code: NRF_SUCCESS.
<info> app: my addr: D0:07:B7:A4:FC:E2
<info> app: Starting temperature measurement.

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481267"]

If you are still not able to see the advertisements, can you please test the attached project? It should start blinking the LEDs every 1 second (2 second period). Does it seem correct? Or is it way to fast/slow?

[/quote]

I couldn't quite get that project setup, so I quickly wrote another one to run on my PCBA that does the same (blinks the light using app timers every 1000ms:

#include "nrf_drv_clock.h"
#include "app_timer.h"
#include "nrf_gpio.h"
#include "boards.h"

#define LED_PIN 6 // LED connected to pin 6
APP_TIMER_DEF(m_led_toggle_timer);

static void led_toggle(void * p_context)
{
    UNUSED_PARAMETER(p_context);
    nrf_gpio_pin_toggle(LED_PIN);
}

static void timers_init(void)
{
    // Initialize the app timer module.
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);

    // Create the timer to toggle the LED every 1 second.
    err_code = app_timer_create(&m_led_toggle_timer, APP_TIMER_MODE_REPEATED, led_toggle);
    APP_ERROR_CHECK(err_code);
}

static void gpio_init(void)
{
    // Initialize the GPIO pin as output with initial value as low (LED off)
    nrf_gpio_cfg_output(LED_PIN);
    nrf_gpio_pin_clear(LED_PIN);
}

int main(void)
{
    // Initialize the LFCLK required for the timers.
    nrf_drv_clock_init();
    nrf_drv_clock_lfclk_request(NULL);

    gpio_init();
    timers_init();

    // Start the timer
    ret_code_t err_code = app_timer_start(m_led_toggle_timer, APP_TIMER_TICKS(1000), NULL);
    APP_ERROR_CHECK(err_code);

    // Enter main loop.
    while (true)
    {
    }
}

and the output looks good to me:

Edit:

I got the ble_app_hrs_pca10040e_s112 example working on both the DK and custom PCBA. First image is on the DK and second is on the custom PCBA (I removed DEVELOP_IN_NRF52832 when on the PCBA as needed).

RE: Can't get BLE device to sleep

Edvin — Tue, 30 Apr 2024 11:56:00 GMT

Hello,

[quote user="prsboy"]

2. I removed it from everywhere I found it:

https://gist.github.com/scripter-co/47fad092cd1815eed748b9d47f33a4a2

[/quote]

ok, I was afraid you removed every instance in the SDK, but that is not the case. Good.

[quote user="prsboy"]I also added the debug/log messages:[/quote]

[quote user="prsboy"]so it seems that everything is working as it should[/quote]

These log messages are coming at a regular speed, right (Like within one second)? Or is it significantly slower when you are using RC than when you are using the SYNTH?

[quote user="prsboy"]just removed it through SES from the preprocessor and the same result[/quote]

Good to know. Make sure you select the "common" in the upper left corner before removing it (I tried to mark it in my screenshot). However, if you removed all like you did in the git diff, then that should have been removed as well.

Advertising every 5 seconds is pretty slow. I see that you tried experimenting with different advertising intervals. Have you tried running one of the simpler samples on your custom board? The ble_app_hrs, for example, isn't dependent on any other peripherals (it uses UART for logging, but you can change that to RTT, or remove it). Also remember to change the clock to the RC oscillator, like you did for your application. Do you see any advertisements there?

Just to explain my thoughts. Usually when there are issues with custom boards, the clock configuration is one of the first things we look into. Seeing as it works if you are using the SYNTH, this suggests that your HFCLK setup is fine, this for two reasons:

1: You are able to pick up the advertising packets, meaning that the packets generated by the radio are correct. The HFCLK is used to send these packets.

2: The synthesized LFLCK is running of the HFLCK, meaning that - at least if the advertising interval seems correct - the HFCLK is also fine.

So this leaves the LFCLK. This is only used to keep track of the time between the packets when you are using the softdevice. So it can be quite off, as long as you are only advertising. The only issue would be that the advertising interval would be a bit off (more than the random 0-10ms added delay).

I noticed a warning when building your application again, that NRFX_RNG_ENABLED was defined more than once. It may be that your current application is slightly different than mine, but can you please try to run the attached application, and let me know what the (RTT) log says, and whether you are able to see the advertisements:

devzone.nordicsemi.com/.../output_5F00_edvin.zip

It should print the actual values (compile time) of the clock configuration definitions. Do you see something like this?

<info> app: NRFX_RNG_ENABLED 1
<info> app: CLOCK_CONFIG_LF_SRC 0
<info> app: NRF_SDH_CLOCK_LF_SRC 0
<info> app: NRF_SDH_CLOCK_LF_RC_CTIV 16
<info> app: NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
<info> app: NRF_SDH_CLOCK_LF_ACCURACY 1
<info> app: checking LFCLK ...
<info> app: LFCLK started!
<info> app_timer: RTC: initialized.
<info> app: my addr: D7:72:C7:D6:4A:E1

devzone.nordicsemi.com/.../2768.blinky.zip

(pca10040e\blank\ses)

Does that work on your board?

Best regards,

Edvin

RE: Can't get BLE device to sleep

prsboy — Mon, 29 Apr 2024 23:51:55 GMT

[quote userid="26071" url="~/f/nordic-q-a/110327/can-t-get-ble-device-to-sleep/481015"]

What exactly does that mean? I just meant that you should remove it from your preprocessor definitions if you are actually running on an nRF52810 chip.

1: Are you actually running it on an nRF52810?

2: Did you remove it from your preprocessor definitions in SES?

[/quote]

1. Yes, I was deploying it on my PCBA (I am using the NRF52DK to flash the PCBA).

2. I removed it from everywhere I found it:

https://gist.github.com/scripter-co/47fad092cd1815eed748b9d47f33a4a2

But I also did exactly what you said in your message and just removed it through SES from the preprocessor and the same result (no BLE signal detected).

---------

I also added the debug/log messages:

<info> app: checking LFCLK ...
<info> app: LFCLK started!
<info> app_timer: RTC: initialized.
<info> CLOCK: Function: nrfx_clock_init, error code: NRF_SUCCESS.
<info> clock: Function: nrf_drv_clock_init, error code: NRF_SUCCESS.
<info> app: Starting temperature measurement.
<info> app: Reading temperature data.
<info> app: Calculated temperature: 22.66 C
<info> app: number: 2266
<info> app: Starting humidity measurement.
<info> app: Reading humidity data.
<info> app: number: 5953
<info> app: BLE EVENT
<info> app: start ble

so it seems that everything is working as it should.

---- 5 hours later ----

Oh! I've spent the the whole day looking into this and I've noticed that the custom board is actually advertising - despite the interval set to advertise every 5 seconds (as an example), when I scan for the device using both laptop/phone, it takes a very long time to pick up the signal (5 mins after started searching):

the DK is picked up straight away. I just happened to notice this after I changed the configuration of NRF Connect to not timeout after 2 minutes and then notice it show up 5 minutes later.

So I guess the question now is, what could cause the BLE advertising to be so intermittent when deployed to the custom PCBA when using RC oscillator? The signal is not regular - the advertising packets are received very sporadically and unreliably.

edit:

I've played around with the advertising interval and timeout and increasing/decreasing the `ble_adv_fast_interval` makes no difference to the ability to pick anything up. Even when I set ble_adv_fast_timeout = 0 it still behaves the same.

RE: Can't get BLE device to sleep

Edvin — Mon, 29 Apr 2024 09:10:01 GMT

[quote user="prsboy"]I have completely removed all reference of DEVELOP_IN_NRF52832.[/quote]

What exactly does that mean? I just meant that you should remove it from your preprocessor definitions if you are actually running on an nRF52810 chip.

1: Are you actually running it on an nRF52810?

2: Did you remove it from your preprocessor definitions in SES?

[quote user="prsboy"]#define NRFX_CLOCK_CONFIG_LOG_ENABLED 1 #define NRFX_CLOCK_CONFIG_LOG_LEVEL 4[/quote]

From apply_old_config.h:

#if defined(CLOCK_CONFIG_LOG_ENABLED)
#undef NRFX_CLOCK_CONFIG_LOG_ENABLED
#define NRFX_CLOCK_CONFIG_LOG_ENABLED  CLOCK_CONFIG_LOG_ENABLED
#endif
#if defined(CLOCK_CONFIG_LOG_LEVEL)
#undef NRFX_CLOCK_CONFIG_LOG_LEVEL
#define NRFX_CLOCK_CONFIG_LOG_LEVEL  CLOCK_CONFIG_LOG_LEVEL
#endif

So try to set CLOCK_CONFIG_LOG_ENABLED = 1 as well, and CLOCK_CONFIG_LOG_LEVEL = 4.

You can verify the values of NRFX_CLOCK_CONFIG_LOG_ENABLED by printing it to your log from your main.c file:

NRF_LOG_INFO("clock log enabled: %d, log_level: %d", NRFX_CLOCK_CONFIG_LOG_ENABLED, NRFX_CLOCK_CONFIG_LOG_LEVEL);

Another check you can do in your application is to add this before you initiate your timers:

void check_clock_source(void)
{
  NRF_LOG_INFO("checking LFCLK ...");
  NRF_CLOCK->TASKS_LFCLKSTART = 1;
  while (NRF_CLOCK->EVENTS_LFCLKSTARTED == false)
  {
    // wait...
  }
  NRF_LOG_INFO("LFCLK started!");

}

int main(void)
{
    ...
    LOG_INIT()
    ...
    check_clock_source();
    ...
    ble_stack_init()

And see if that function returns, or if it is stuck. I believe it should return, because you shouldn't be able to initiate the softdevice without an LFCLK.

If you don't figure it out, can you please upload the updated application that can reproduce the issue you are seeing on a DK?

Best regards,

Edvin

RE: Can't get BLE device to sleep

prsboy — Thu, 25 Apr 2024 20:47:13 GMT

I have completely removed all reference of DEVELOP_IN_NRF52832.

When i try and deploy it on my custom PCBA I can see logs as usual:

<info> app_timer: RTC: initialized.
<info> app: Starting temperature measurement.
<info> app: Reading temperature data.
<info> app: Calculated temperature: 22.64 C
<info> app: number: 2264
<info> app: Starting humidity measurement.
<info> app: Reading humidity data.
<info> app: Calculated humidity: 64.30%
<info> app: number: 6430
<info> app: BLE EVENT
<info> app: start ble
<info> app: BLE EVENT
<info> app: Advertising event: Idle
<info> app: asleep
<info> app: Awake and start advertising
<info> app: Starting temperature measurement.
<info> app: Reading temperature data.
<info> app: Calculated temperature: 22.75 C
<info> app: number: 2275
<info> app: Starting humidity measurement.
<info> app: Reading humidity data.
<info> app: Calculated humidity: 63.59%
<info> app: number: 6359
<info> app: BLE EVENT
<info> app: start ble
<info> app: BLE EVENT
<info> app: Advertising event: Idle
<info> app: asleep

but I'm unable to pick anything up when scanning for the device which is very strange, the device behaves exactly how it does when I set the LFCLK to XTAL, apart from I can't detect the BLE signal. Is there any way I'm able to check the state of the LFCLK? I tried setting

#define NRFX_CLOCK_CONFIG_LOG_ENABLED 1
#define NRFX_CLOCK_CONFIG_LOG_LEVEL 4

but no additional logs are output to the console (as seen from the console output above).

RE: Can't get BLE device to sleep

Edvin — Thu, 25 Apr 2024 10:46:55 GMT

[quote user="prsboy"]

LFCLK should not be needed then.

[/quote]

In that case, I don't see any benefits from using an LFXTAL, so at least if you haven't designed it in already, I wouldn't bother.

With the configuration that you have there, when you are not able to detect the BLE device, does the log say anything relevant?

Is the BLE stack enabled as it should? Does the application reach the advertising_start() function? Do you see any logs at all if you enable logging and use your custom board? Did you remember to remove the DEVELOP_IN_NRF52832 preprocessor definition?

Best regards,

Edvin

RE: Can't get BLE device to sleep

prsboy — Wed, 24 Apr 2024 09:50:06 GMT

That's interesting, it sounds like (as I'm just using BLE advertising) that a external LFCLK should not be needed then.

I had set these from reading through the following document which was quite useful (see section for "Internal RC low-frequency oscillator (LFRC)"). The problem I have is that when I set (as you mentioned in your post), the configuration:

#define CLOCK_CONFIG_LF_SRC 0
#define NRFX_CLOCK_CONFIG_LF_SRC 0
#define NRF_SDH_CLOCK_LF_SRC 0
#define NRF_SDH_CLOCK_LF_RC_CTIV 16
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
#define NRF_SDH_CLOCK_LF_ACCURACY 1

the BLE device is no longer detectable. What I mean by this is that I can no longer detect the signal using my laptop or mobile phone (both are using nRF Connect bluetooth app).

It sounds to me like you're saying this should work. My assumption was that it was a hardware issue which caused the RC oscillator to not be stable enough... I will just double check this with one of the example applications and updating the above configuration.

RE: Can't get BLE device to sleep

Edvin — Wed, 24 Apr 2024 08:24:31 GMT

Depending on your application you may or may not benefit from adding an LFXTAL. The disadvantage of an external LFCLK is that you have one more component that will draw current, but the advantage is that if you are (often) in a connection, you will have a more accurate LFCLK, which means that the radio will be able to more accurately determine when it will receive a radio packet, which means that it can narrow down the timeslot where the radio will be active (in RX mode).

This is however only when you are in a connection. If your application is a beacon that is only advertising, the increased accuracy of the LFCLK doesn't come with any benefits.

BR,

Edvin

RE: Can't get BLE device to sleep

Edvin — Wed, 24 Apr 2024 08:20:21 GMT

Hello Nathan,

Right. An external LFXTAL is one way (I assume you meant externla LF clock, and not HF clock, since you probably have an external HF clock already. That one is mandatory, but the LF XTAL is optional).

Yes, the SYNTH is an easy way to make sure that the LFCLK is working properly, but this is not intended for production, as it is way too power-hungry.

Let me try to get this straight, so that we get the RC oscillator up and running:

There are several sets of definitions in sdk_config.h regarding the clock configuration. If you search this file for "LF_SRC", you will find:

NRFX_CLOCK_CONFIG_LF_SRC
CLOCK_CONFIG_LF_SRC
NRF_SDH_CLOCK_LF_SRC

Try to make these align. You can check the file apply_old_config.h to see how NRFX_CLOCK_CONFIG_LF_SRC and CLOCK_CONFIG_LF_SRC work together, but I usually just set them equal to one another, so I don't need to remember which one overwrites the other.

The NRF_SDH_CLOCK_LF_SRC is not part of apply_old_config.h, but it is used by the softdevice. When this is set to 0 (NRF_CLOCK_LF_SRC_RC, you need to set NRF_SDH_CLOCK_LF_RC_CTIV, NRF_SDH_CLOCK_LF_RC_TEMP_CTIV and NRF_SDH_CLOCK_LF_ACCURACY accordingly.

This is not very intuitive, but if you look in nrf_sdm.h (which will be included in you application project), you can look at the declaration of the struct nrf_clock_lf_cfg_t. In the parameter description it says:

uint8_t rc_temp_ctiv; /**< Only for ::NRF_CLOCK_LF_SRC_RC: How often (in number of calibration
intervals) the RC oscillator shall be calibrated if the temperature
hasn't changed.
0: Always calibrate even if the temperature hasn't changed.
1: Only calibrate if the temperature has changed (legacy - nRF51 only).
2-33: Check the temperature and only calibrate if it has changed,
however calibration will take place every rc_temp_ctiv
intervals in any case.

@note Must be 0 if source is not ::NRF_CLOCK_LF_SRC_RC.

@note For nRF52, the application must ensure calibration at least once
every 8 seconds to ensure +/-500 ppm clock stability. The
recommended configuration for ::NRF_CLOCK_LF_SRC_RC on nRF52 is
rc_ctiv=16 and rc_temp_ctiv=2. This will ensure calibration at
least once every 8 seconds and for temperature changes of 0.5
degrees Celsius every 4 seconds. See the Product Specification
for the nRF52 device being used for more information.*/

So if you have NRF_CLOCK_LF_SRC_RC (0), then you must also set:

NRF_SDH_CLOCK_LF_RC_CTIV 16
NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
NRF_SDH_CLOCK_LF_ACCURACY 1

If not, the initialization of the softdevice will fail, as you can see from nrf_sdh.c, line 76:

#if (   (NRF_SDH_CLOCK_LF_SRC      == NRF_CLOCK_LF_SRC_RC)          \
     && (NRF_SDH_CLOCK_LF_ACCURACY != NRF_CLOCK_LF_ACCURACY_500_PPM))
    #warning Please select NRF_CLOCK_LF_ACCURACY_500_PPM when using NRF_CLOCK_LF_SRC_RC
#endif

Try that, and let me know whether it works.

Best regards,

Edvin

RE: Can't get BLE device to sleep

prsboy — Tue, 23 Apr 2024 15:52:32 GMT

Hey Edvin!

I set the LFCLK source to RC but unfortunately I was reminded as to why it was set to SYNTH to start with - without setting it to SYNTH the BLE module would not work.

I'm looking at getting a hardware review (and adding a external HF clock to the PCBA).

Nathan

RE: Can't get BLE device to sleep

prsboy — Fri, 19 Apr 2024 12:28:59 GMT

Amazing, thank you so much! I'll give this a go as soon as I get back to my DK and let you know the results!

I honestly would never have been able to work this out - it's interesting that setting LFCLK to SYNTH causes this behaviour!

Quick question, what's the best way to conditionally include DEVELOP_IN_NRF52832? I will alternate between the DK and my PCBA, so would prefer not to have to constantly switch.

edit: apologies for making your life more difficult by modifying the LFCLK value inline instead of defining it at the top!