/** Initialize the low power ticker
*
*/
void lp_ticker_init(void)
{
lptmr_config_t lptmrConfig;
if (lp_ticker_inited) {
return;
}
lp_ticker_inited = true;
/* Setup low resolution clock - RTC */
if (!rtc_isenabled()) {
rtc_init();
RTC_DisableInterrupts(RTC, kRTC_AlarmInterruptEnable | kRTC_SecondsInterruptEnable);
RTC_StartTimer(RTC);
}
RTC->TAR = 0; /* Write clears the IRQ flag */
NVIC_ClearPendingIRQ(RTC_IRQn);
NVIC_SetVector(RTC_IRQn, (uint32_t)rtc_isr);
NVIC_EnableIRQ(RTC_IRQn);
/* Setup high resolution clock - LPTMR */
LPTMR_GetDefaultConfig(&lptmrConfig);
/* Use 32kHz drive */
CLOCK_SetXtal32Freq(OSC32K_CLK_HZ);
lptmrConfig.prescalerClockSource = kLPTMR_PrescalerClock_2;
LPTMR_Init(LPTMR0, &lptmrConfig);
LPTMR_EnableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
NVIC_ClearPendingIRQ(LPTMR0_IRQn);
NVIC_SetVector(LPTMR0_IRQn, (uint32_t)lptmr_isr);
EnableIRQ(LPTMR0_IRQn);
}
void rtc_write(time_t t) {
if (t == 0) {
t = 1;
}
RTC_StopTimer(RTC);
RTC->TSR = t;
RTC_StartTimer(RTC);
}
void rtc_init(void) {
rtc_config_t rtcConfig;
RTC_GetDefaultConfig(&rtcConfig);
RTC_Init(RTC, &rtcConfig);
/* Setup the RTC 32KHz oscillator */
rtc_setup_oscillator(RTC);
RTC_StartTimer(RTC);
}
static void rtc_isr(void)
{
uint32_t sr = RTC->SR;
if (sr & RTC_SR_TOF_MASK) {
// Reset RTC to 0 so it keeps counting
RTC_StopTimer(RTC);
RTC->TSR = 0;
RTC_StartTimer(RTC);
} else if (sr & RTC_SR_TAF_MASK) {
RTC_DisableInterrupts(RTC, kRTC_AlarmInterruptEnable);
RTC->TAR = 0; /* Write clears the IRQ flag */
/* Wait subsecond remainder if any */
if (lptmr_schedule) {
LPTMR_SetTimerPeriod(LPTMR0, lptmr_schedule);
LPTMR_EnableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
LPTMR_StartTimer(LPTMR0);
} else {
lp_ticker_irq_handler();
}
} else if (sr & RTC_SR_TIF_MASK) {
RTC_DisableInterrupts(RTC, kRTC_TimeOverflowInterruptEnable);
}
}
void rtc_write(time_t t)
{
RTC_StopTimer(RTC);
RTC->TSR = t;
RTC_StartTimer(RTC);
}
