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.
Laurent MEUNIER
jeromecoutant
Wolfgang Betz
Helmut Tschemernjak
Helmut Tschemernjak
Bartek Szatkowski