Bluetooth is not working

[Venus_Bilandi]

We have developed a PCB using nrf52840 controller. It's a brand new controller. I am using SEGGER embedded studio for programing.

I have flashed an example code ble_app_blinky_pca10056_s140 on the controller,.

This code isn't working on this controller. there is no problem in flashing the code but it's not working.

In above picture is the last location where code stops working.

This is mine main function

int main(void)
{
// Initialize.
log_init();

nrf_gpio_cfg_output(Led1);
nrf_gpio_cfg_output(Led2);
nrf_gpio_cfg_output(Led3);
nrf_gpio_cfg_output(Led4);
nrf_gpio_pin_write(LEDBUTTON_BUTTON, 1);

//leds_init();
timers_init();
//buttons_init();
power_management_init();
ble_stack_init();
gap_params_init();
gatt_init();
services_init();
advertising_init();
conn_params_init();

// Start execution.
NRF_LOG_INFO("Blinky example started.");
advertising_start();

// Enter main loop.
for (;;)
{
idle_state_handle();
}
}

Is this happening because of soft devices?

[Edvin]

Hello,

The SDK examples assumes that you have an external LFXTAL, which I assume that your custom PCB doesn't, as this is optional.

You need to configure the example to use the internal RC Oscillator instead of an external LFXTAL. Open sdk_config.h in your example project and change set the following settins:

#define NRFX_CLOCK_CONFIG_LF_SRC 0
#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

They should be defined, so you need to find them and change the numbers.

Let me know whether that works for your PCB.

Best regards,

Edvin

[Venus_Bilandi]

Hello,

Edvin, We have an external crystal on board.

And  I am using these settings.

#define NRFX_CLOCK_CONFIG_LF_SRC 1
#define CLOCK_CONFIG_LF_SRC 1
#define NRF_SDH_CLOCK_LF_SRC 1
#define NRF_SDH_CLOCK_LF_RC_CTIV 0
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 0
#define NRF_SDH_CLOCK_LF_ACCURACY 7

please help

[Edvin]

Can you try the settings that I provided please? If that works, and your current settings do not, it may indicate that you need to tweak your settings.

Besides, the XTAL inside the ring in your screenshot is the HFXTAL, which is mandatory. The LFXTAL (32kHz, not MHz) is optional, and I can't see it on your layout.

Please try.

[Venus_Bilandi]

Hello Edvin 

Do we need a LFXTAL (32Khz) to operate Bluetooth, or Bluetooth data transfer?

[awneil]

No, you don't need it - but your configuration has to be correct to work without it.

If your configurations says that there is an LFXTAL, when there really isn't one - it is not going to work!

[Edvin]

No. As I said, it is optional whether or not to use an LFXTAL when you are using our SoftDevice (Bluetooth stack).

However, the SoftDevice does require an LFCLK. If you don't have an LFXTAL you need to tell the SoftDevice to use the RC Oscillator instead of the LFXTAL by setting the settings that I wrote in my first reply.

Explanation:

LFCLK: 32kHz clock.

LFXTAL: a physical HardWare component generating the 32kHz frequency used by the LFCLK.

RC Oscillator: An oscillator located inside the chip that can be used instead of an external LFXTAL.