nrf51 Bluetooth issue- ble_app_uart stopped working

[bitpapi]

I have tried running the ble_app_uart project on nrf51 DK. Initially the program compiled and ran perfectly(I was able to see that device on nrf UART app). Later when I used the nrf51 DK to program nrf51822 on a custom PCB I was able to make the blinky project work. However when I tried to program the ble_app_uart project again on the PCb and nrf51DK it compiles and programs but I am unable to see the device on the nrf UART app.

TLDR- ble_app_uart worked on the nrf51DK. Later I try to use nrfDK to program ble-app_uart on nrf51822 on PCB it stops working on both the DK and PCB. Blinky LED stil works on both.

[Susheel Nuguru]

what kind of oscillator does you custom chip use? most probably you have selected wrong clock. The ble_uart_example uses external oscillator that is available on DK and i am guessing this is not available on your custom board?

in main.c->ble_stack_init, you have

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, NULL);

You need to change it to use internal RC clock for example change the above line to

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION, NULL);

[bitpapi]

I have an external oscillator so that's not an issue. Main issue is that bluetooth is undiscoverable on nrf51Dk from time to time. Sometimes I program it and the LED1 that signals the bluetooth is on starts blinking.Sometimes it doesn't. Is it an issue with the dev kit?

[Susheel Nuguru]

why dont you reset the devkit. Do a full erase by "nrfjprog --eraseall" on cmd prompt. and try the application again. I am assuming that you have not made any changes to the ble_app_uart example that you are trying on the DK. If it has worked once, then i doubt that there are any defects on DK.