ble_app_uart example not working nRF52833 and S140

[trashman]

Hello. I tried to run ble_peripheral/ble_app_uart example from the newest SDK (17.2) on my ebyte e73 with nRF52833 onboard, but without success. I used softdevice S140 (tried both 7.0.1 and 7.2.0 versions). So far I've been successful with running this example on another ebyte with nRF52832 onboard. I don't think that it is a hardware issue, because I tried programming code which does not require soft device and it worked pretty well. To my surprise ble_app_beacon example with S132 also worked. To flash the program i do the following (using openocd):

init_reset halt; init; halt; nrf51 mass_erase; reset; program "/path/to/nrf528_xxaa.out" verify; program "/path/to/s140_nrf52_7.2.0_softdevice.hex" 0x0 verify

I tried debugging with GDB, it seems that the problem is encountered when `sd_softdevice_enable` is called. 

Any ideas what could be the cause?

[Vidar Berg]

Hello,

Did you select the pca10100 configuration (board name for nRF52833 DK) when you built the ble_app_uart project for your module?

I tried debugging with GDB, it seems that the problem is encountered when `sd_softdevice_enable` is called. 

 It's almost always a problem with the low frequency clock source if the program hangs inside sd_softdevice_enable() call. Not sure if that is the case here, but as a test, please try to change to the 'SYNTH' clock source in sdk_configh (NRF_SDH_CLOCK_LF_SRC==NRF_CLOCK_LF_SRC_SYNTH) to see if you get the same result.

Can you post the CPU registers you see in GDB when the code hangs?

[trashman]

Hello, thank you for your reply. Yes, I used pca10100 configuration, I tried both provided hex file and compiled by myself. It seems you were right about clock source. After this little change I can now see Nordic_UART device in nRF Connect app. Thanks a lot!

[Vidar Berg]

Hello,

No problem, thanks for the update. It's only a bit suprising that the ble_app_beacon example worked then, it selects the external 32 KHz crystal by default as ble_app_uart.

[trashman]

Yeah, but there is an answer for that. I used my own modified beacon example. I've just checked sdk_configs in both places. The one which worked (beacon) had NRF_SDH_CLOCK_LF_SRC set to NRF_CLOCK_LF_SRC_RC, while the other had NRF_CLOCK_LF_SRC_XTAL. The XTAL version worked with my previous ebyte, but it seems it does not work with the new one (other model).