ble uart example won't run when built from source

[Ray Wendt]

Hi,

I'm working on getting the ble UART example running. I flashed the softdevice (s140), then programmed the board (pca10056) with the provided hex file, and encountered the exact same issue as in this question: devzone.nordicsemi.com/.../, where the board will advertise but my phone won't connect to it (iphone 7, iOS 11)

I added the code from the response to that question, but once I built the project the board did not even enter advertising mode or output anything over the serial port. I went back and verified that the code still does not work even without the changes recommended in the question linked above. I tried with the pca10040 board and its corresponding softdevice, and using an older version of the SDK on both boards, and any program that I built had the same issue. The provided hex file for the pca10040 is completely functional. Update: the same behavior is observed with a pca10028 board.

I also tried adding another log to the main routine as follows to see if it was hanging during the ble initialization, but I still get nothing at all over the serial port. I also did a similar test with attempting to turn on an LED instead of logging and that did not work either.

// Initialize.
err_code = app_timer_init();
APP_ERROR_CHECK(err_code);

uart_init();
log_init();

NRF_LOG_INFO("test\r\n"); //added this line

buttons_leds_init(&erase_bonds);
ble_stack_init();
gap_params_init();
gatt_init();
services_init();
advertising_init();
conn_params_init();

printf("\r\nUART Start!\r\n");
NRF_LOG_INFO("UART Start!");
err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
APP_ERROR_CHECK(err_code);

Does anyone have any insight as to why it's not working or further suggestions for debugging?

[Deepansh]

Hi, Ray which IDE you are using and do step by step debugging and see after which line your code stuck or it works till the ends. if it works till the end without stucking then do it by making log statements as a comment

[endnode]

Hi Ray, even before doing step-by-step debugging (which is anyway very limited as you cannot run it during any time-restricted action such as BLE link) could you elaborate on how nRF5 SDK V14.2.0 pre-compiled HEX file(s) work on your PCA10056 nRF52840 PDK board? If these work but once you "touch" it (try to build yourself) then it looks like problem is in your build set-up. WOuld you agree?;)

[endnode]

Just to clarify why do I ask: there is no such bug indicate in nRF5 SDK v14.x bug list so I believe the examples shouldn't have any issue with iOS11 devices connecting (otherwise this thread will need attention from Nordic support team to reproduce and file the bug on their side). If this is true then again it indicates you just do something wrong on your side...

[Ray Wendt]

I discovered that I have to flash the softdevice after I program the board with the hex file that I built, opposite from the way I had been doing it, and then the example works. For some reason the provided hex file does not require the softdevice to be flashed after the board is programmed, which was the source of my confusion.

[endnode]

That's what I suggested, I believe it's even mentioned in tutorials or SDK release notes: pre-compiled HEX files are merged with Soft Device when applicable. So it's not some magic or mystical reason, it's simply because you flashed both app and SD so it worked.