SLAZ183P October 2012 – May 2021 MSP430F2481
COMP Module
Functional
Configuring the port disable register (CAPD)
According to the user's guide, each bit in the CAPD register should correspond with its associated port I/O number. For example, when "bit 0" of CAPD is set, the port disable function of pin Px.0 is enabled; "bit 1" controls Px.1, and so on (where Px is the port that contains the comparator inputs). However, on this device, the bits of the CAPD register correspond with the Comparator_A input number. For example, "bit 0" of CAPD controls the CA0 input, "bit 1" controls CA1, etc. This difference matters when the port I/O number is not the same as the comparator input number.
If the wrong CAPD bit is set, the port I/O function for the wrong pin will be disabled. Also, the analog signal applied to the comparator input pin being used may cause a parasitic current to flow from Vcc to GND. See the Comparator_A+ chapter of the MSP430x2xx Family User's Guide (SLAU144) for more information on CAPD.
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