After beating my head against the toolchain for quite a while, I finally managed to get SES to compile the ble_app_uart for the nRF51822 using the s130 soft device. It works as expected with the development kit board (most recent PCA10028 - purchased 7/2018). The device advertises Nordic_UART, and I can find and connect to the service from LightBlue.
However, when I install the same code on my target platform, it fails silently, hanging at the call to SOFTDEVICE_HANDLER_INIT. My assumption was that this was caused by a difference between the clock on the DK board and the clock on the target, so I simply passed NULL to the SOFTDEVICE_HANDLER_INIT call. According to the documentation:
Low frequency clock source and accuracy. If NULL the clock will be configured as an rc source with rc_ctiv = 16 and .rc_temp_ctiv = 2 In the case of XTAL source, the PPM accuracy of the chosen clock source must be greater than or equal to the actual characteristics of your XTAL clock.
Making that change (null clock parameter) fixed the hang, but did not fix the problem - the board never advertises the UART service. I assume that I need to do something to enable the internal RC clock. Any suggestions on getting it working? Most of the posts I found made reference to using something like: NRF_CLOCK_LFCLKSRC_RC_250_PPM_8000MS_CALIBRATION - but that no longer seems to be part of the SDK (I'm using 12.3). Argh...
The target is a custom board with a module from Nordic's list of module vendors. (Here's a link: https://fccid.io/2AA72-PTR5518/User-Manual/User-Manual-2123475) It claims to have a 32 kHz, 25 PPM clock, but this post makes me suspect that claim.
