Alarm for tickless idle

Program wakeups for FreeRTOS tickless sleep. More...

Collaboration diagram for Alarm for tickless idle:

Functions
void	tr_rtc_setup_alarm (uint64_t delta_ms)
	Program an RTC alarm to fire approximately delta_ms in the future.

Detailed Description

Program wakeups for FreeRTOS tickless sleep.

Function Documentation

tr_rtc_setup_alarm()

void tr_rtc_setup_alarm

(

uint64_t

delta_ms

)

Program an RTC alarm to fire approximately delta_ms in the future.

Parameters

[in]

delta_ms

Relative delay in milliseconds. If 0, it is coerced to 1 ms.

Converts (HW_now_ms + max(delta_ms,1)) to an absolute calendar value and arms the hardware alarm via the HAL. Intended for FreeRTOS tickless idle, where the alarm interrupt wakes from WFI/Sleep or triggers a deep‑sleep wake/reset, depending on the platform power configuration.

Example (integration sketch)

void vPortSuppressTicksAndSleep(TickType_t expectedIdle)
{
    if (expectedIdle == 0) return;
    if (eTaskConfirmSleepModeStatus() == eAbortSleep) return;
 
    const uint32_t tick_ms = 1000u / configTICK_RATE_HZ;
    uint32_t sleep_ms = expectedIdle * tick_ms;
 
    tr_rtc_setup_alarm(sleep_ms);
    uint64_t before = tr_rtc_get_uptime_ms();
 
    // enter low power: WFI / SLEEP / DEEP_SLEEP (platform policy)
    platform_enter_low_power(expectedIdle);
 
    uint64_t after = tr_rtc_get_uptime_ms();
    TickType_t slept = (TickType_t)((after - before) / tick_ms);
    if (slept > expectedIdle) slept = expectedIdle;
    vTaskStepTick(slept);
}