Bluetooth broadcast errors in low and high temperature conditions

[Zion]

Hi，

     SDK:ncs2.6.1. The main program runs in the app core, and the net core is included as a child image. The Bluetooth broadcast is normal when tested at room temperature, but after being tested in the high and low temperature box, it is found that the Bluetooth broadcast suddenly disappears when tested below -30℃ and 60℃. At present, it is suspected that it is because of the external high-speed crystal problem.

What I want to ask is that

① when do most of these problems appear, may be the hardware configuration, software configuration problems?

② How can I solve this problem?

The app core is configured as follows:

# External clock
CONFIG_SOC_ENABLE_LFXO=y
# CONFIG_SOC_LFXO_CAP_EXTERNAL=y
# CONFIG_SOC_LFXO_CAP_INT_6PF=y
# CONFIG_SOC_LFXO_CAP_INT_7PF=y
# CONFIG_SOC_LFXO_CAP_INT_9PF=y
# CONFIG_SOC_HFXO_CAP_DEFAULT=y
# CONFIG_SOC_HFXO_CAP_EXTERNAL=y
CONFIG_SOC_HFXO_CAP_INTERNAL=y
CONFIG_SOC_HFXO_CAP_INT_VALUE_X2=24

app.overlay:

&clock {
    status = "okay";	
	lfxo: lfxo {
		// source = "LFXO";
		compatible = "nordic,nrf-lfxo";
		#clock-cells = <0>;
		clock-frequency = <32768>;
		// zephyr,pm-device-runtime-auto;
		status = "okay";
	};

	hfxo: hfxo {
		// source = "HFXO";   
		compatible = "nordic,nrf-hfxo";
		#clock-cells = <0>;
		clock-frequency = <DT_FREQ_M(32)>;
		// zephyr,pm-device-runtime-auto;
		status = "okay";
	};	
};

net_core.overlay:

&gpiote {
	status = "disabled";
};

&gpio0 {
	status = "disabled";
};

&gpio1 {
	status = "disabled";
};

&uart0 {
	status = "disabled";
};

arduino_serial: &uart0{
	status = "disabled";
};


&ieee802154 {
	status = "disabled";
};

&wdt {
	status = "okay";
};

&rng {
	status = "okay";
};

&radio {
	status = "okay";
};

&temp {
	status = "disabled";
};

[Kazi Afroza Sultana]

Hello,

''t is found that the Bluetooth broadcast suddenly disappears when tested below -30℃ and 60℃. At present, it is suspected that it is because of the external high-speed crystal problem.'' The reason could be related to both hardware and software probably. 

Can you please send us the crystal datasheet? Does it support wider temperature range?

[Zion]

I am sure that the test of external high-speed crystal oscillator is good. As for the manual, I need to find it for you tomorrow.

[Zion]

But I have a question, I use onoff_request to switch the external high-speed crystal clock in my application, how can I be sure that Bluetooth is not using the external high-speed crystal clock when I control to turn off the external high-speed clock?

[Zion]

306010055_FC-135_物料规格书-1.pdf306011503_惠伦_1S32000049_Datasheet.pdf

306010055_FC-135_物料规格书-1.pdfI have uploaded the datasheet for the external high-speed/low-speed crystals we are currently using, and they should meet the requirements. From my testing, it seems that in my application, if I don't use the onoff_request to toggle the external high-speed clock, Bluetooth works fine and can broadcast normally even under high and low temperatures. Therefore, I would like to know if toggling the external high-speed clock in the application could conflict with the Bluetooth protocol stack.

[Kazi Afroza Sultana]

Hello,

The specification of crystal looks ok. 

Usually, SoftDevice manages the HFCLK. Your application can request SoftDevice to set the clock source with the external crystal. you can read this documentation High-frequency clock configuration.

If your application does not require any manual control of the HFCLK, its best to let the SoftDevice manage the clock. Did you try to set on off for HF crystal in following way?

sdk-nrf/samples/peripheral/radio_test/src/main.c at e895510c7cad107d815070c02923e82564ed0337 · nrfconnect/sdk-nrf · GitHub