Texas Instruments MSP430x4xx - Manual (Page 471)

Scan IF Operation
24-11 Scan IF
Comparator and DAC
The analog input signals are converted into digital signals by the comparator
and the programmable 10-bit DAC. The comparator compares the selected
analog signal to a reference voltage generated by the DAC. If the voltage is
above the reference the comparator output will be high. Otherwise it will be low.
The comparator output can be inverted by setting SIFCAINV. The comparator
output is stored in the selected output bit and processed by the processing
state machine to detect motion and direction.
The comparator and the DAC are turned on and off by SIFCA(tsm) signal and
the SIFDAC(tsm) signal when needed by the timing state machine. They can
also be permanently enabled by setting the SIFCAON and SIFDACON bits.
During sensitive measurements enabling the comparator and DAC with the
SIFCAON and SIFDACON bits may improve resolution.