Dear All,
I am getting crazy trying to understand how "input offset compensation" works for MSP430F2132's comparator.
According to MSP430F2132's data sheet (p40), it appears that: input offset can be cancelled by using CAEX bit to invert the comparator_A+ inputs on successive measurements.
My point of interest is when input difference is within the input offset tolerance (+/- 30mV) of the comparator. In order to get the idea, I summarized all four cases in the attached table. Please assume that VCA0 is the known reference voltage (given by the design) and VCA1 is the measured voltage (changes over the time).
When looking at comparator output CAOUT and !CAOUT, I do not see how to get the comparison result.
For a given offset, it looks like the outputs are the same in both cases (VCA0>VCA1 and VCA0<VCA1). How am I supposed to tell which input is greater/smaller than the other one??
I would appreciate if anyone could describe, step by step, the required process in order to get the correct comparator output using input offset cancellation.
Thx in advance,
Stephane
