nrf5340 read temperature by nrfx_temp_measure() function sometimes return -53℃ at room temperature

[tianwanjie]

following is my code

#include <nrfx_temp.h>

static void temp_handler(int32_t temperature)
{ 
    m_soc_temperature = temperature;
    printk("Temperature (Celcius): %d \n",temperature / 4);
}

static void soc_temperature_peripheral_init(void)
{
    int err;
    nrfx_temp_config_t temp_config = NRFX_TEMP_DEFAULT_CONFIG;
    err = nrfx_temp_init(&temp_config,temp_handler);
    IRQ_CONNECT(TEMP_IRQn,5,nrfx_temp_irq_handler,NULL,0);
    if (err!=NRFX_SUCCESS) 
    {	
	    printk("soc_temperature_peripheral_init error %d\n", err);
    }
}

int main()
{
    soc_temperature_peripheral_init();
    for(;;)
    {
        k_sleep(K_SECONDS(1));
        if(NRFX_SUCCESS == nrfx_temp_measure()){
            LOG_INF("soc temperature is %d",m_soc_temperature/4);
        }
    }
}

prj.conf file :

CONFIG_NRFX_TEMP=y

[Kenneth]

Can you provide chip markings of the nRF5340 you have and which NCS version you are working on?

Kenneth

[Stephan Walter]

Any news on this issue? We also see negative values in the range -44℃ ... -67℃ at room temperature. This is with SDK version 2.1.1, using the Zephyr sensor driver.

[Kenneth]

Hello,

Can you share a simplified project I can build and run on the nRF5340-DK?

Kenneth

[Stephan Walter]

Hi Kenneth,
Thanks for offering to help. I have so far been unable to create a minimal project that shows the problem.

Our application firmware shows the problem when run on a nRF5340-DK, but for complexity and security reasons I can't share that.

What I have noticed is that after flashing the application core firmware using VS Code, the temperature values seem to be correct. Typical values are TEMP=0x00000066. Resetting the chip from the VS Code debugger does not change that.

But when I reset the chip using SW5 on the DK, suddenly I get negative values, e.g. TEMP=0xFFFFFF2B.

I will try to further narrow down the problem.

--Stephan

[Kenneth]

Hi,

Sounds like a plan, one question though, if this is an application with BLE (softdevice controller)?

If yes, then you should possible check out YOPAN-87 description:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/softdevice_controller/limitations.html# 

Edit: It's not the errata issue itself I want you to be aware of, but the fact that the temperature sensor is used by the network controller, hence you should use the BT_HCI_OP_VS_READ_CHIP_TEMP api to read the temperature if the softdevice controller is used in your application.

Best regards,
Kenneth