Use the `mbed_sdk_inited` flag to correct the `HAL_GetTick()` behavior
after waking up from deep sleep mode. `ticker_read_us()` must not be
used to read us_ticker timestamp after waking up until the us_ticker
context is restored. More detailed description in issue #8117.
Fixes#8117
Correctly detect and handle the low power run mode when entering and exiting sleep mode.
The generic `hal_sleep` implementation tries to exit LPR mode always, resulting in a spin-loop during a critical section (disabled IRQ).
The new approach returns from LPR to Run mode if enabled (LPR bit set), enters sleep, and resets to the original state on wakeup (WFI).
As suggested by Russ Butler in mbed-os issue #7328, and until there is an
implementation of mbed-os issue #4408, we are implementing a workaround
at HAL level to check if there is any ongoing serial transfer (which happens
if HW FIFO is not yet empty).
In case a transfer is ongoing, we're not entering deep sleep and
return immediately.
- RTC_SSR for the subseconds
- RTC_TR for the time
- RTC_DR for the date
These registers were accessed through shadow registers which are synchronized with PCLK1 (APB1 clock).
They are now accessed directly in order to avoid waiting for the synchronization duration.
There are cases where a call hal_deepsleep would overflow the idle task
stack, especially in developper or debug profile.
In order to avoid this case, we split ForceClockOutofDeepSleep
into two separate functions the two structure RCC_ClkInitStruct and
RCC_OscInitStruct are not allocated at the same time.
Tests have shown that there is hich-up on MSI clock during the setup phase.
If this stabilization phase happens when application has restarted again
this can have side effects, like grambled UART characters typically.
So we're adding a delay before hading-over back to application.
With this modification, on NCULEO_L476RG, the wake-up time is increased
from 2ms to 2,5ms.
If possible this should be improved in the future to save 500 microseconds
of wak-up time. See TODO
There are cases where HW registers are found in unpexcepted state when
exiting Deep Sleep only few micro-seconds after it was entered.
By using an internal clock that does not depend on anythin and clocking
the system without using PLL, this allows SetSysClock default configuration
to run fine whatever possible configuration we find the HW in when
exiting Deep Sleep.
Also we shall restore interrupts only after all cloks are back to
expected running state.
STM32L0, L4, F7 and few F4 chip are supporting LPTIM feature.
We propose to allow user to use LPTIM for MBED LowPowerTimer API instead of using RTC wakeup timers.
By default, all targets that are supporting this feature have been configured.
Add sleep/deepsleep functions to platform layer which are replacing HAL
functions with the same name, rename existing symbols in HAL layer
to hal_sleep/hal_deepsleep. This way sleep functions
are always available, even if target doesn't implement them, which makes
the code using sleep clearer. It also enables us to make decision on in
which builds (debug/release) the sleep will be enabled.
jeromecoutant
Martin Kojtal
Markus Siglreithmaier
Filip Jagodzinski
Laurent Meunier
Cruz Monrreal
bcostm
Laurent MEUNIER
Wolfgang Betz
Helmut Tschemernjak
Helmut Tschemernjak
Bartek Szatkowski