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Hall Sensor XOR

Question asked by Eric Williams on Sep 19, 2019
Latest reply on Sep 19, 2019 by Robin_Shen



In the KV31F sub-family reference manual, there's a handy note regarding using the two 2-CH FTM modules (FTM1 and FTM2) in input capture mode for hall sensor decoding. Apparently one of the SIM_SOPT4 register bits controls the input to FTM2 CH1. If the three hall sensors are connected to FTM1 CH0, FTM1 CH1, and FTM2 CH0 then setting this bit appropriately will result in the "Exclusive-OR" of the three hall sensor lines which could result in reduced complexity in calculation.


My question is regarding the interpretation of "Exclusive OR" for 3 signals, as there are typically two interpretations. Is this an "Only 1" (xor output is true only if only one input is true) or an "odd parity" (xor output is true if an odd number of inputs are true) interpretation?