a 9600 baud serial interface does not need a hardware UART. these
changes switch the SDM power meter implementation to use a software
serial instance instead. this is desirable as hardware UARTs are scarce
and users need them for JK BMS and VE.Direct interfaces.
the destructor will block for way too long if we keep holding the
polling mutex while performing a transcation with the SDM power meter.
when reading, we now release the lock. afterwards, i.e., in between
transactions, we check the stop flag so the task terminates in a timely
manner once asked to do so.
a 1-phase SDM power meter does not know about power or voltage of phase
2 or 3. do not publish values to the respective MQTT topics when using a
single phase SDM power meter.
instead of reading the main config's powermeter struct(s), the
individual power meters now are instanciated using a copy of their
respective config. this allows to instanciate different power meters
with different configs. as a first step, this simplifies instanciating
power meters for test purposes.
all power meter providers now have their own configuration struct
defined. a respective method to serialize and deserialize the provider
config is implemented for each provider.
"powertotal" is always published and it is published by the base class
directly. other values are still published by the derived classes, but
use a base class method, which takes care that a common base topic is
used in particular.
it is important to separate the capabilities of each power meter
provider into their own class/source file, as the providers work
fundamentally different and their implementations must not be
intermangled, which made maintenance and improvements a nightmare
in the past.
