Errate 2.17.4 says:
> Upon enabling the RTC tamper detection feature, a false tamper
> detection *can* be reported by the RTC.
It turns out that this spurious event is not always generated.
If RTC alarm is used and the CPU was previously woken from hibernate
by RTC, it *can* happen that the false tamper event is *not* generated.
In this case, we will block indefinitely on the mutex.
To solve this, add a timeout to the event.
Also poll the event instead of using a mutex, as we have already set
`PM->SLEEPCFG.bit.SLEEPMODE` at this point.
The DAC can have some start-up delay.
If we try to write to it before it's ready, it will get stuck.
This happens now that `tests/driver_dac_dds` immediately sets a DAC
value after init.
The samd2x class of MCUs doesn't have this bit, but a quick test on
samd10 shows that it might not be nececary there - the DAC does not
get stuck when writing to it immediately after init.
`flashpage_write_raw()` got renamed to `flashpage_write()`.
Now `sam0_flashpage_aux_write_raw()` is the only remaining 'raw'
function, even though it behaves just like `flashpage_write()`.
So let's also rename that for consistency.
On samd5x only the RTC can wake the CPU from Deep Sleep (pm modes 0 & 1).
The external interrupt controller is disabled, but we can use the tamper
detection of the RTC.
If an gpio interrupt is configured on one of the five tamper detect pins,
those can be used to wake the CPU from Deep Sleep / Hibernate.
The Cortex-m0 based ATSAM devices can use the Single-cycle I/O Port for
GPIO. This commit modifies the gpio_t type to use this port when
available. It is mapped back to the peripheral memory space for
configuration access. When it is not available, the _port_iobus() and
_port() functions behave identical, which is the case for the samd51.
This changes the prefixes of the symbols generated from USEMODULE and
USEPKG variables. The changes are as follow:
KCONFIG_MODULE_ => KCONFIG_USEMODULE_
KCONFIG_PKG_ => KCONFIG_USEPKG_
MODULE_ => USEMODULE_
PKG_ => USEPKG_
If we disable an external interrupt, GPIO events that would generate an interrupt will still set the interrupt flag.
That means once we enable the interrupt again, a stale interrupt will be triggered.
This is surprising and probably not what the user wants, unfortunately the API documentation is not very clear about what to expect.
There is however no way to drop those intermediate interrupts with the current API.
Ignoring the events that occurred while the GPIO interrupt were disabled is probably the right (and expected) thing to.
Move common code into helper functions and extract the commands
that differ between normal and RWWEE page reading / writing.
This cuts down on `#ifdef` use.
The RTC and RTT share the same peripheral, so they can also
share the same code.
This is needed to integrate the Tamper Detection into common
RTC/RTT code.
We don't need to read-modify-write the CTRLA register to disable
the UART.
The entire CTRLA register is re-written just a few lines below, so
we can just set it to 0 to disable the UART.
There is also no need to reset the UART since we re-write all config
registers in init.
