This commit simplifies ticker interrupt set function and handler.
There were issues around the 16 bits timer wrap-around timing as we were
aligning interrupts with wrap-around limits (0xFFFF) and then reading
TIM_MST->CNT again in timer_update_irq_handler which could lead
to crossing case with the wrap-around (TIM_FLAG_UPDATE) case.
Now we're using the 16 lower bits of the timestamp as the reference from
using in set_compare and never changing it. There is also no need to set
comparator again in timer_update_irq_handler. This is more robust and
also more efficient.
Move to a single more reliable implementation of us_ticker_read()
There were historically 2 versions of us_ticker_read() implementation.
The one removed here was not reliable because us_ticker_read() can be
called in interrupt context which means that TIM_MST->CNT would have
wrapped around while SlaveCounter is not yet updated. So there is a need
to check the TIM_FLAG_UPDATE inside this function, which was not done in
the implementation that is removed here.
- RCC init: unused clock was enabled without any init parameters
- ADC: a parameter setting was missing
- GPIO: mode was not allowed by ST HAL API
- tick: init value was too high for 16b
Laurent MEUNIER
jeromecoutant
bcostm