Our design has an nRF5340 with RV3028C7 to provide the 32 kHz clock via P0.00.
If I configure P0.00 as a digital input, I can see the pin toggling.
However, if I use the code below to try and switch from to the external clock, the EVENTS_LFCLKSTARTED doesn't happen. Any idea why this would be?
NRF_CLOCK->LFCLKSRC = CLOCK_LFCLKSRC_SRC_LFXO << CLOCK_LFCLKSRC_SRC_Pos;
NRF_OSCILLATORS->XOSC32KI.INTCAP = OSCILLATORS_XOSC32KI_INTCAP_INTCAP_External << OSCILLATORS_XOSC32KI_INTCAP_INTCAP_Pos;
NRF_OSCILLATORS->XOSC32KI.BYPASS = OSCILLATORS_XOSC32KI_BYPASS_BYPASS_Enabled << OSCILLATORS_XOSC32KI_BYPASS_BYPASS_Pos;
NRF_P0->PIN_CNF[0] = GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos |
GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos |
GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos |
GPIO_PIN_CNF_INPUT_Disconnect << GPIO_PIN_CNF_INPUT_Pos;
NRF_P0->PIN_CNF[1] = GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos |
GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos |
GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos |
GPIO_PIN_CNF_INPUT_Disconnect<< GPIO_PIN_CNF_INPUT_Pos;
NRF_CLOCK->LFCLKALWAYSRUN = CLOCK_LFCLKALWAYSRUN_ALWAYSRUN_AlwaysRun << CLOCK_LFCLKALWAYSRUN_ALWAYSRUN_Pos;
NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
NRF_CLOCK->TASKS_LFCLKSTART = 1;
uint32_t count = 0;
while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0) {
// wait for LFCLK to start
++count;
}
