* fix: pulse driver with 32bit timers
* fix(mpm): clear RX buffer before signature
* fix: add some debouncing on soft-serial start bit detection
This helps coping with spurious impulses on S.PORT created by payload sent over PPM pin (X10E).
* fix: whenever the RXNE bit is set, read the register
... regardless of errors. That allows for reducing the effect of detected errors.
