QUERY · ISSUE

STM32 sleep wake time problem

openby china-zhangdjopened 2021-09-24updated 2024-10-02

port-stm32

rtc.wakeup(ms)
machine.lightsleep(ms)

Do these two functions use the same wake-up source?
What is the maximum value of ms?

CANDIDATE · PULL REQUEST

ports/stm32h5: add sleep modes and RTC alarm wakeup

mergedby renestraubopened 2023-10-21updated 2023-11-03

port-stm32

This PR adds support for machine.lightsleep() and machine.deepsleep() for STM32H5. Wakeup is possible via RTC.alarm(). machine.reset_cause() reports the proper code when waking up from on of those.

r = RTC()
r.wakeup(5_000)
machine.deepsleep()

# System goes to sleep for 5 secs

# Wakes up via reset, all state is lost
MicroPython v1.20.0-288-g3a153d92f-dirty on 2023-10-21; NUCLEO_H563ZI with STM32H563ZI
Type "help()" for more information.

machine.reset_cause()
4
machine.DEEPSLEEP_RESET
4

i = 1
r = RTC()
r.wakeup(5_000)
machine.lightsleep()

# System goes to sleep for 5 secs

# Wakes up from Stop mode, state is retained

machine.reset_cause()
4
i
1

This PR fixes #12697

Assessment

S Sonnet · medium

The query is a support question asking whether rtc.wakeup() and machine.lightsleep() share the same wake-up source on STM32, and what the maximum ms value is. The candidate PR adds lightsleep/deepsleep support for STM32H5 with RTC-based wakeup, and its code examples implicitly demonstrate that rtc.wakeup() is the wake source used with machine.lightsleep(). However, the PR does not address the maximum ms value question, is specific to STM32H5 (not STM32 in general), and does not directly answer the query's questions. It provides relevant context about how these two functions interact but leaves the query's concerns open.

Suggested action

Leave the issue open. Point the user to PR #12761 as an example showing that rtc.wakeup() feeds into machine.lightsleep() as the wake source on STM32H5, and ask them to consult the STM32 HAL documentation or RTC wakeup timer limits for the maximum ms value (which depends on the RTC prescaler configuration).

STM32 sleep wake time problem

ports/stm32h5: add sleep modes and RTC alarm wakeup

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