FW is not running on the nRF52832 on Coin cell

[barfiii]

Hi,

We are encountering an issue where the existing firmware does not run on the chip when powered by a coin cell, even though a 3.3V power supply is available from the coin cell. The firmware application only starts running after performing a software reset using nRF Connect while the power supply is connected via J-Link. How can this issue be resolved on the firmware side without adding a hardware reset switch?

Regards,

Sai Krishna

[Kazi Afroza Sultana]

Hello,

''We are encountering an issue where the existing firmware does not run on the chip when powered by a coin cell, even though a 3.3V power supply is available from the coin cell.'' Which firmware you are working on? does it work if you power the device by external power supply?

''The firmware application only starts running after performing a software reset using nRF Connect while the power supply is connected via J-Link.''

You meant it worked when you did nrfjprog --reset each time before running the program?

''How can this issue be resolved on the firmware side without adding a hardware reset switch??''

I think it's your custom module. Is there any internal component in your software is working but not present on the module? You can check it and change the config file in accordance with board.  For example: you may not have the DCDC converter on the board, but it may be enabled in the application. Setting this CONFIG_BOARD_ENABLE_DCDC=n in prj.conf file ca solve the issue perhaps. 

Thanks.

BR

Kazi

[barfiii]

Hi Kazi,

''We are encountering an issue where the existing firmware does not run on the chip when powered by a coin cell, even though a 3.3V power supply is available from the coin cell.'' Which firmware you are working on? does it work if you power the device by external power supply?

My firmware application is designed to blink an LED. However, the LED does not blink when the device is powered using a coin cell. The blinking starts working only after performing a software reset and powering the device using J-Link.

''The firmware application only starts running after performing a software reset using nRF Connect while the power supply is connected via J-Link.''

You meant it worked when you did nrfjprog --reset each time before running the program?

Yes. I'm using reset option under the connected devices in nRF Connect.

''How can this issue be resolved on the firmware side without adding a hardware reset switch??''

I think it's your custom module. Is there any internal component in your software is working but not present on the module? You can check it and change the config file in accordance with board.  For example: you may not have the DCDC converter on the board, but it may be enabled in the application. Setting this CONFIG_BOARD_ENABLE_DCDC=n in prj.conf file ca solve the issue perhaps. 

We are using a custom board based on the nRF52 MCU, where P0.21 (Reset) is left unconnected. That’s why I asked if any changes are required on the firmware side to ensure the application runs on the MCU using a coin cell after it has been programmed. Will the code run automatically once the MCU is powered up?

BR

Krishna

[Kazi Afroza Sultana]

Hello Krishna,

Reset pin has internal pull up resistor; even if you leave it floating it would have effect on application. So, you need to set the 

CONFIG_GPIO_AS_PINRESET=n in prj.cnf file.

You also mentioned that application works when you preform the soft reset each time. try to set the above config and see it helps. 

Did you disable the DC-DC converter as I mentioned on my last reply?

One thing I need to mention that blinky sample typically uses the external crystal 32.768kHz connected to P0.00 and P0.01 as the default LFCLK source. 

The system waits until the crystal starts counting. 

Do you have external crystal? if not you can use the internal RC oscillator for the LFCLK by setting CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y in prj.conf file.