/**
* @brief Clock calibration function used by rtc_clk_cal and rtc_clk_cal_ratio
* @param cal_clk which clock to calibrate
* @param slowclk_cycles number of slow clock cycles to count
* @return number of XTAL clock cycles within the given number of slow clock cycles
*/
static uint32_t rtc_clk_cal_internal(rtc_cal_sel_t cal_clk, uint32_t slowclk_cycles)
{
/* Enable requested clock (150k clock is always on) */
int dig_32k_xtal_state = REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_XTAL32K_EN);
if (cal_clk == RTC_CAL_32K_XTAL && !dig_32k_xtal_state) {
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_XTAL32K_EN, 1);
}
if (cal_clk == RTC_CAL_8MD256) {
SET_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_CLK8M_D256_EN);
}
/* Prepare calibration */
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_CLK_SEL, cal_clk);
CLEAR_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START_CYCLING);
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_MAX, slowclk_cycles);
/* Figure out how long to wait for calibration to finish */
uint32_t expected_freq;
rtc_slow_freq_t slow_freq = REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ANA_CLK_RTC_SEL);
if (cal_clk == RTC_CAL_32K_XTAL ||
(cal_clk == RTC_CAL_RTC_MUX && slow_freq == RTC_SLOW_FREQ_32K_XTAL)) {
expected_freq = 32768; /* standard 32k XTAL */
} else if (cal_clk == RTC_CAL_8MD256 ||
(cal_clk == RTC_CAL_RTC_MUX && slow_freq == RTC_SLOW_FREQ_8MD256)) {
expected_freq = RTC_FAST_CLK_FREQ_APPROX / 256;
} else {
expected_freq = 150000; /* 150k internal oscillator */
}
uint32_t us_time_estimate = (uint32_t) (((uint64_t) slowclk_cycles) * MHZ / expected_freq);
/* Start calibration */
CLEAR_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START);
SET_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START);
/* Wait the expected time calibration should take.
* TODO: if running under RTOS, and us_time_estimate > RTOS tick, use the
* RTOS delay function.
*/
ets_delay_us(us_time_estimate);
/* Wait for calibration to finish up to another us_time_estimate */
int timeout_us = us_time_estimate;
while (!GET_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_RDY) &&
timeout_us > 0) {
timeout_us--;
ets_delay_us(1);
}
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_XTAL32K_EN, dig_32k_xtal_state);
if (cal_clk == RTC_CAL_8MD256) {
CLEAR_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_CLK8M_D256_EN);
}
if (timeout_us == 0) {
/* timed out waiting for calibration */
return 0;
}
return REG_GET_FIELD(TIMG_RTCCALICFG1_REG(0), TIMG_RTC_CALI_VALUE);
}
uint64_t rtc_time_get(void)
{
SET_PERI_REG_MASK(RTC_CNTL_TIME_UPDATE_REG, RTC_CNTL_TIME_UPDATE);
while (GET_PERI_REG_MASK(RTC_CNTL_TIME_UPDATE_REG, RTC_CNTL_TIME_VALID) == 0) {
ets_delay_us(1); // might take 1 RTC slowclk period, don't flood RTC bus
}
SET_PERI_REG_MASK(RTC_CNTL_INT_CLR_REG, RTC_CNTL_TIME_VALID_INT_CLR);
uint64_t t = READ_PERI_REG(RTC_CNTL_TIME0_REG);
t |= ((uint64_t) READ_PERI_REG(RTC_CNTL_TIME1_REG)) << 32;
return t;
}
void rtc_clk_wait_for_slow_cycle(void)
{
REG_CLR_BIT(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START_CYCLING | TIMG_RTC_CALI_START);
REG_CLR_BIT(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_RDY);
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_CLK_SEL, RTC_CAL_RTC_MUX);
/* Request to run calibration for 0 slow clock cycles.
* RDY bit will be set on the nearest slow clock cycle.
*/
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_MAX, 0);
REG_SET_BIT(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START);
ets_delay_us(1); /* RDY needs some time to go low */
while (!GET_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_RDY)) {
ets_delay_us(1);
}
}
uint32_t rtc_sleep_start(uint32_t wakeup_opt, uint32_t reject_opt)
{
REG_SET_FIELD(RTC_CNTL_WAKEUP_STATE_REG, RTC_CNTL_WAKEUP_ENA, wakeup_opt);
WRITE_PERI_REG(RTC_CNTL_SLP_REJECT_CONF_REG, reject_opt);
/* Start entry into sleep mode */
SET_PERI_REG_MASK(RTC_CNTL_STATE0_REG, RTC_CNTL_SLEEP_EN);
while (GET_PERI_REG_MASK(RTC_CNTL_INT_RAW_REG,
RTC_CNTL_SLP_REJECT_INT_RAW | RTC_CNTL_SLP_WAKEUP_INT_RAW) == 0) {
;
}
/* In deep sleep mode, we never get here */
uint32_t reject = REG_GET_FIELD(RTC_CNTL_INT_RAW_REG, RTC_CNTL_SLP_REJECT_INT_RAW);
SET_PERI_REG_MASK(RTC_CNTL_INT_CLR_REG,
RTC_CNTL_SLP_REJECT_INT_CLR | RTC_CNTL_SLP_WAKEUP_INT_CLR);
return reject;
}