Hi,
We are trying to get our nRF54L15 running, but are running into clock issues. The hardware is configured without an external 32kHz crystal, so we want to rely on the NRF54's internal RC for our low-speed clock. We need to configure the GRTC to use the internal RC, not the external LFXO. We have set the following clock-related Kconfig options to accomplish this:
```
CONFIG_CLOCK_CONTROL=y
CONFIG_CLOCK_CONTROL_NRF=y
CONFIG_NRFX_CLOCK=y
CONFIG_NRF_GRTC_TIMER=y
CONFIG_NRF_GRTC_START_SYSCOUNTER=y
CONFIG_NRFX_GRTC=y
CONFIG_NRFX_CLOCK_LF_SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_SYNTH=n
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n
CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC_CALIBRATION=y
CONFIG_CLOCK_CONTROL_NRF_CALIBRATION_LF_ALWAYS_ON=y
```
We also have our device-tree set up as follows (relevant snippets):
```
#include <nordic/nrf54l15_cpuapp.dtsi>
&lfxo {
status = "disabled";
load-capacitors = "internal";
load-capacitance-femtofarad = <7000>;
clock-frequency = <32768>;
};
&hfxo {
status = "okay";
clock-frequency = <32000000>;
load-capacitors = "internal";
load-capacitance-femtofarad = <17000>; // 17pF per BM15C datasheet
};
&grtc {
owned-channels = <0 1 2>;
status = "okay";
};
&clock {
status = "okay";
};
```
However, when we run our application with the debugger enabled, we are stuck in clock initialization -- in the GRTC initialization. github.com/.../nrfy_grtc.h. More precisely, we get stuck inside of the sys counter ready check. Upon inspecting the GRTC registers, we see that the GRTC is configured in CLKSEL to use the LFXO. However, it should be it should be configured to use the RC per my Kconfig options. I have verified from KConfig output that the necessary config options are enabled.
We are at a loss as to why the GRTC is not configured to use the RC, as it is explicitly set to do so in our configuration. Any help would be greatly appreciated.
