SNIS189D June 2015 – June 2018 LMT01
The comparator hysteresis determines the noise level that the signal can support without causing the comparator to trip falsely and resulting in an inaccurate pulse count. The comparator hysteresis is set by the precision of the MSP430 and what thresholds it is capable of. For this case, as the input signal transitions high, the comparator threshold is dropped by 77 mV. If the noise on the signal is kept below this level as it transitions, the comparator will not trip falsely. In addition, the MSP430 has a digital filter on the COMP_B output that be used to further filter output transitions that occur too quickly.