nrf ble uart example does not run after a power-on reset

RE: nrf ble uart example does not run after a power-on reset

Hung Bui — Fri, 09 Feb 2024 12:33:44 GMT

Hi Akshaya,
It's strange that configuring the pin as pull up help the issue. Normally with UART you don't need to put a pull up in the RX pin.

What do you have on the other side of UART ? which device do you connect to ?
Please check what you have on the PCB on the RX pin, is there any chance you have a pull down resistor on it ?
Please try to reproduce the issue on a DK (for NRF52832 or nRF52840)

RE: nrf ble uart example does not run after a power-on reset

Akshaya Balu — Thu, 08 Feb 2024 09:17:17 GMT

Hi Hung,

Thanks for the response.

My issue is resolved now.

The issue was resolved when I enabled RX pin with the internal pin pull-up by the following code.

nrf_gpio_cfg_input(RX_PIN_NUMBER, NRF_GPIO_PIN_PULLUP);

RE: nrf ble uart example does not run after a power-on reset

Hung Bui — Wed, 07 Feb 2024 12:30:30 GMT

Hi Akshaya,

Could you clarify which sample are you testing with, where exactly BLE_peripheral_uart located ? We have ble_app_uart but I am not so sure if it's what you testing with.
What did you mean by "getting detected" ? Did you mean it was advertising ?
Could you explain the reason for the change you made:
#define RETARGET_ENABLED 0
deleted the file segger_rtt_printf.c
In flash_placement.xml, remove size="0x4"
Change library I/O to RTT

What kind of error if you dont change them ?

Have you followed the instruction here on how to build for nRF52811 ? https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/nrf52811_user_guide.html?cp=9_5_2_5_1_3#ug_52811_project

Please try to start with some simple application, for example blinky or uart (no BLE) and check if it works on your board before you move to the peripheral uart example. You may want to get familiar with how to debug the application, not just observing if it's advertising or not.