How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Fri, 26 May 2017 11:46:55 GMT

No effect, as in the LFCLKSTAT reads 0x00010000 after you've triggered the TASKS_LFCLKSTOP task? If the LFCLKSRC is set to Xtal, and you trigger the TASKS_LFCLKSTART do you get the EVENTS_LFCLKSTARTED event?

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Tue, 23 May 2017 09:47:46 GMT

After the exception occurs, I've tried NRF_CLOCK->TASKS_LFCLKSTOP = 1, But there is no effect. I've tested external low-frequency crystals did not work at this moment.

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Tue, 23 May 2017 07:20:34 GMT

Triggering the TASKS_LFCLKSTOP task, i.e. NRF_CLOCK->TASKS_LFCLKSTOP = 1; should stop the LFCLK.

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Mon, 22 May 2017 13:23:55 GMT

What method can make NRF_CLOCK->LFCLKSTAT == 0？

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Mon, 22 May 2017 06:59:28 GMT

Could you clarify what you mean with "remove NRF_CLOCK->LFCLKSTAT"?

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Fri, 19 May 2017 14:34:45 GMT

Have a way to remove NRF_CLOCK - > LFCLKSTAT status?

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Fri, 19 May 2017 13:26:47 GMT

Have you confirmed that you have the correct load caps for the external crystal? I have never seen this issue before, i.e. that the XTAL does not start up correctly when you set NRF_CLOCK_LF_SRC_XTAL as source, provided that a crystal with the correct specs and the correct load caps are used.

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Fri, 19 May 2017 12:39:11 GMT

When using external low-frequency crystals, if NRF_CLOCK - > LFCLKSTAT = = 0 x00010000, the program will stuck in sd_softdevice_enable (p_clock_lf_cfg softdevice_fault_handler); In the use of JLink burning program, I met many times this exception, air upgrade also appeared in the process.

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Fri, 19 May 2017 08:12:44 GMT

I apologize, I referred to an incorrect register value( 0x8001) and corrected my comment. The default value of the LFCLKSRC is 0x00000000 so if you start the LFCLK using the TASKS_LFCLKSTART task then you will read 0x00010000. I still do not understand why you need to check this.

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Thu, 18 May 2017 15:23:33 GMT

yes.I read 0x00010000 from the LFCLKSTAT register. I use projects: SDK12.0.0 ; examples\ble_peripheral\ble_app_hrs_freertos The following code:

int main(void)
{
    ret_code_t err_code;
    uint32_t lfclk_state = 1;
    
    while(lfclk_state)
    {
        lfclk_state = NRF_CLOCK->LFCLKSTAT; //lfclk_state =0x00010000
    }
    
    err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);
....
}

After the exception occurs, I put the low-frequency clock configuration set to use internal frequency clock, the program can run, but related to low frequency clock driver is invalid, such as app_timer, WDT, etc

After this exception occurs,Cut off the chip power supply, and then to electricity to make the program run normally

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Thu, 18 May 2017 07:31:08 GMT

After initialization, you mean that after you've called sd_softdevice_enable with the following clock config

    // Low frequency clock source to be used by the SoftDevice
#define NRF_CLOCK_LFCLKSRC      {.source        = NRF_CLOCK_LF_SRC_XTAL,            \
                                 .rc_ctiv       = 0,                                \
                                 .rc_temp_ctiv  = 0,                                \
                                 .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM}

then you read 0x00010000 from the LFCLKSTAT register?

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Wed, 17 May 2017 12:40:46 GMT

Before 52832 program into the main function, initialize the clock: Under normal circumstances: NRF_CLOCK - > LFCLKSTAT = 0; After the abnormal: NRF_CLOCK - > LFCLKSTAT = 0 x00010000, (1 low frequency clock is still running, 00 said RC internal clock)

Now, initialize the clock before I join lfclk_stop (), the program will stuck waiting for the clock stopped while (nrf_clock_lf_is_running ())

    // Low frequency clock source to be used by the SoftDevice
#define NRF_CLOCK_LFCLKSRC      {.source        = NRF_CLOCK_LF_SRC_XTAL,            \
                                 .rc_ctiv       = 0,                                \
                                 .rc_temp_ctiv  = 0,                                \
                                 .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM}

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Fri, 05 May 2017 07:56:58 GMT

You can the trigger the TASKS_LFCLKSTART task and wait for the EVENTS_LFCLKSTARTED and/or read the LFCLKSTAT register. See this page in the NRF52832 PS.

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Thu, 04 May 2017 14:19:28 GMT

Why do you need to detect "abnormal external low-frequency crystals" ? I assume that you know which crystal that is on your pcb?

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Thu, 04 May 2017 14:07:52 GMT

How to detect abnormal external low-frequency crystals, then automatically switch to the internal low-frequency crystals？

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

juge90 — Thu, 04 May 2017 14:07:22 GMT

How to detect abnormal external low-frequency crystals, then automatically switch to the internal low-frequency crystals？

RE: How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

bjorn-spockeli — Fri, 28 Apr 2017 08:49:05 GMT

You need to modify the NRF_CLOCK_LFCLKSRC in the pca10040.h or custom_board.h to the following

#define NRF_CLOCK_LFCLKSRC      {.source        = NRF_CLOCK_LF_SRC_RC,            \

                                 .rc_ctiv       = 16,                             \

                                 .rc_temp_ctiv  = 2,                              \

                                 .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_250_PPM }