Can't detect the custom device after uploading ble_app_beacon example (nRF52810)

[mertklic]

Hi,

I developed a custom board with nRF52810. Here is my schematic: 

Layout:

I can succesfully upload the "ble_app_beacon" example in SDK17.1.0 with softdevice112 using Segger Embedded Studio.

I power my device with STLink and use JTAG to program it. I connected the GND of STLink and JTAG to achive this. 

I can debug too.

Dont mind the commented lines. I tried to toggle a LED in order to make sure that i can program the device correctly and it worked.

The problem is device is not detectable. I dont think the BLE works properly. Here is my setup. I connected an external 2.4GHz antenna in case my PCB antenna is not good.

I dont know what to do. 

Any help would be great.

Regards,

Mert 

[Håkon Alseth]

Hi,

 

Both softdevice.hex + application is loaded, which is good.

Could you try to run this sequence and see if the HFXO starts up properly?

NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

 

If you hang in the while-loop, there is a problem with your 32M xtal.

 

Kind regards,

Håkon

[mertklic]

Hi Håkon,

Thank you for your quick reply.

The code stucks at while loop. You are correct.

Tomorrow I will check my hardware with oscilloscope and make sure i have good crystal. Maybe i will solder a new one.

Thanks,

Regards,

Mert

[Håkon Alseth]

Hi Mert,

 

Good to hear that you found the source of the problem. Usually this is because of excess solder, so try ohm'ing from the can of the crystal to the XC1/XC2 pins. If they read as <10 ohm, it is likely a short from the side of the crystal or underneath it.

 

Kind regards,

Håkon

[mertklic]

Hi Håkon,

The problem was with solder of XC1 and XC2 pins on the processor. Now thanks to you i finally be able to detect my device. Now I have one more question. My low frequency crystal does not seem to work even though i resoldered everything and make sure the connections are good.I think it happens because of the code We added previously.

NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

Do you think i am right? I will try it when i go back home.

Regards,

Mert

[Håkon Alseth]

Hi,

 

With 12 pF loading caps, your 32k xtal needs to have a CL of 8 pF (C=2*CL-4pF).

You should check the spec of your 32k xtal.

 

If all this aligns, you can start the lfclk simillarly as the hfclk:

/* Start low frequency crystal oscillator for app_timer(used by bsp)*/
NRF_CLOCK->LFCLKSRC            = (CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos);
NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
NRF_CLOCK->TASKS_LFCLKSTART    = 1;

while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0)
{
}

 

Same thing applies, if it hangs in that loop, you have lfclk problems.

Note that this must be called before softdevice init.

 

Kind regards,

Håkon

[mertklic]

Hi Håkon,

For now I only have a xtal with CL of 12pF. I bought a new one and waiting for it to replace.

I ran the same project with new code included and there was no problem. The beacon still works without getting stuck at while loop.

But when i observe the crystal with my oscilloscope, i still dont see any clock signal.

the breakpoint also works.

I made some research and seems like it is good to have lf crystal to save power.

Why do you think i dont see any signal on oscilloscope?

Regards,

Mert

[Håkon Alseth]

Hi,

 

If the firmware is not stuck in the loop, and your BT link works, the LFCLK is setup correctly.

SoftDevice has a dependency on the LFCLK as well as the HFXO, so without those it will not advertise.

mertklic said:

But when i observe the crystal with my oscilloscope, i still dont see any clock signal.

Loading the xtal with a probe will highly likely change the amplitude of the signal, so it will go down to < 100 mVpp.

 

Setup a app_timer instance, with a known interval, and toggle a pin in the handler instead. This will give you a indicator of the accuracy of the LFCLK.

 

Kind regards,

Håkon

[mertklic]

Hi Håkon

Thank you for your help. I solved all my problems.

Regards,

Mert