lp_ticker driver is the known registered user of RTC handler API.
In case, a lp_ticker is set in the past, the lp_ticker_fire_interrupt
will be called which itself sets the RTC interrupt as pending by calling
NVIC_SetPendingIRQ(RTC_WKUP_IRQn). This all happens without actual
programing of the RTC wake-up.
As a result the RTC HW and corresponding HAL layer doesn't expect an
interrupt to happen and will not call HAL_RTCEx_WakeUpTimerEventCallback.
To sove this situation, we will not use HAL_RTCEx_WakeUpTimerEventCallback
weak definition but rather call handler whenever an RTC interrupt fires.
As reported by MBED user Fran6Jack:
I2C bus are usually 5V tolerant on all STM32 processor.
If an external device on the I2C bus requires 5V operation,
we usually acheive it by using 5V external pull-ups on the bus.
Since signaling uses open-drain output on I2C for both signal SCL and SDA
any 5V tolerant MCU will work on a 5V I2C bus. Having pull-up activated on a 5V externally pull bus, cause the pin to clamp on the STM32 die diode and could damage the IC (There is a note in STM32 datasheet specifying this issue).
It is understood by all the community that I2C bus should always be
externally pulled by physical resistor. I2C initialization should then
be ALWAYS OpenDrainNoPull by default.
Up to now, this I2C driver was setting pull up by default as it helps
basic testing, like 1 master and 1 slave, conencted with 2 wires without
any external pull ups. This will not work anymore after this commit and
applications tests or examples needs to be modified to explicitely
configure pull ups ... But it is safer to follow reference manual
guidelines.
Decrease the interrupt stack from 2k down to 1k so there is enough
ram to build all the tests with tickless enabled. In general, targets
should not need an interrupt stack greater than 1k with mbed-os.
Rather than Unlocking flash during flash object creation, and leaving
the flash possibly continuously unlocked a(s object might bever be freed),
we decide to Unlock then Lock again at each erase or program call.
Fixing regression introduced in commit
"Ticker: add fire interrupt now function".
In above mentioned commit, the management of timestamp being in the past
has been moved to higher layer (hal/mbed_ticker_api.c), but the reset of
oc_int was missing when implementing the new us_ticker_fire_interrupt
function - which is fixed now.
Jimmy Brisson
Pavel Sorejs
Laurent MEUNIER
bcostm
andreas.larsson
jeromecoutant
Martin Kojtal
Russ Butler
Kevin Gilbert