nrfx_err_t nrfx_rtc_cc_set(nrfx_rtc_t const * const p_instance,
uint32_t channel,
uint32_t val,
bool enable_irq)
{
NRFX_ASSERT(m_cb[p_instance->instance_id].state != NRFX_DRV_STATE_UNINITIALIZED);
NRFX_ASSERT(channel<p_instance->cc_channel_count);
nrfx_err_t err_code;
uint32_t int_mask = RTC_CHANNEL_INT_MASK(channel);
nrf_rtc_event_t event = RTC_CHANNEL_EVENT_ADDR(channel);
nrf_rtc_event_disable(p_instance->p_reg, int_mask);
nrf_rtc_int_disable(p_instance->p_reg, int_mask);
val = RTC_WRAP(val);
if (m_cb[p_instance->instance_id].reliable)
{
nrf_rtc_cc_set(p_instance->p_reg,channel,val);
uint32_t cnt = nrf_rtc_counter_get(p_instance->p_reg);
int32_t diff = cnt - val;
if (cnt < val)
{
diff += RTC_COUNTER_COUNTER_Msk;
}
if (diff < m_cb[p_instance->instance_id].tick_latency)
{
err_code = NRFX_ERROR_TIMEOUT;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
}
else
{
nrf_rtc_cc_set(p_instance->p_reg,channel,val);
}
if (enable_irq)
{
nrf_rtc_event_clear(p_instance->p_reg,event);
nrf_rtc_int_enable(p_instance->p_reg, int_mask);
}
nrf_rtc_event_enable(p_instance->p_reg,int_mask);
NRFX_LOG_INFO("RTC id: %d, channel enabled: %lu, compare value: %lu.",
p_instance->instance_id,
channel,
val);
err_code = NRFX_SUCCESS;
NRFX_LOG_INFO("Function: %s, error code: %s.", __func__, NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
ret_code_t nrf_drv_rtc_cc_set(nrf_drv_rtc_t const * const p_instance,
uint32_t channel,
uint32_t val,
bool enable_irq)
{
ASSERT(m_cb[p_instance->instance_id].state != NRF_DRV_STATE_UNINITIALIZED);
ASSERT(channel<p_instance->cc_channel_count);
uint32_t int_mask = RTC_CHANNEL_INT_MASK(channel);
nrf_rtc_event_t event = RTC_CHANNEL_EVENT_ADDR(channel);
nrf_rtc_event_disable(p_instance->p_reg, int_mask);
nrf_rtc_int_disable(p_instance->p_reg, int_mask);
val = RTC_WRAP(val);
if (m_cb[p_instance->instance_id].reliable)
{
nrf_rtc_cc_set(p_instance->p_reg,channel,val);
uint32_t cnt = nrf_rtc_counter_get(p_instance->p_reg);
int32_t diff = cnt - val;
if (cnt < val)
{
diff += RTC_COUNTER_COUNTER_Msk;
}
if (diff < m_cb[p_instance->instance_id].tick_latency)
{
return NRF_ERROR_TIMEOUT;
}
}
else
{
nrf_rtc_cc_set(p_instance->p_reg,channel,val);
}
if (enable_irq)
{
nrf_rtc_event_clear(p_instance->p_reg,event);
nrf_rtc_int_enable(p_instance->p_reg, int_mask);
}
nrf_rtc_event_enable(p_instance->p_reg,int_mask);
return NRF_SUCCESS;
}
void common_rtc_set_interrupt(uint32_t us_timestamp, uint32_t cc_channel,
uint32_t int_mask)
{
// The internal counter is clocked with a frequency that cannot be easily
// multiplied to 1 MHz, therefore besides the translation of values
// (microsecond <-> ticks) a special care of overflows handling must be
// taken. Here the 32-bit timestamp value is complemented with information
// about current the system up time of (ticks + number of overflows of tick
// counter on upper bits, converted to microseconds), and such 64-bit value
// is then translated to counter ticks. Finally, the lower 24 bits of thus
// calculated value is written to the counter compare register to prepare
// the interrupt generation.
uint64_t current_time64 = common_rtc_64bit_us_get();
// [add upper 32 bits from the current time to the timestamp value]
uint64_t timestamp64 = us_timestamp +
(current_time64 & ~(uint64_t)0xFFFFFFFF);
// [if the original timestamp value happens to be after the 32 bit counter
// of microsends overflows, correct the upper 32 bits accordingly]
if (us_timestamp < (uint32_t)(current_time64 & 0xFFFFFFFF))
{
timestamp64 += ((uint64_t)1 << 32);
}
// [microseconds -> ticks, always round the result up to avoid too early
// interrupt generation]
uint32_t compare_value =
(uint32_t)CEIL_DIV((timestamp64) * RTC_INPUT_FREQ, 1000000);
// The COMPARE event occurs when the value in compare register is N and
// the counter value changes from N-1 to N. Therefore, the minimal safe
// difference between the compare value to be set and the current counter
// value is 2 ticks. This guarantees that the compare trigger is properly
// setup before the compare condition occurs.
uint32_t closest_safe_compare = common_rtc_32bit_ticks_get() + 2;
if ((int)(compare_value - closest_safe_compare) <= 0)
{
compare_value = closest_safe_compare;
}
nrf_rtc_cc_set(COMMON_RTC_INSTANCE, cc_channel, RTC_WRAP(compare_value));
nrf_rtc_event_enable(COMMON_RTC_INSTANCE, int_mask);
}
