C8051F380/1/2/3/4/5/6/7/C
8.1. Comparator Multiplexers
C8051F380/1/2/3/4/5/6/7/C devices include an analog input multiplexer to connect Port I/O pins to the
comparator inputs. The Comparator inputs are selected in the CPTnMX registers (SFR Definition 8.5 and
SFR Definition 8.6). The CMXnP2–CMXnP0 bits select the Comparator positive input; the CMXnN2–CMX-
nN0 bits select the Comparator negative input.
Important Note About Comparator Inputs: The Port pins selected as comparator inputs should be con-
figured as analog inputs in their associated Port configuration register, and configured to be skipped by the
Crossbar (for details on Port configuration, see Section “20.3. General Purpose Port I/O” on page 161).
VDD
CP0 +
+
CP0 - -
GND
VDD
CP1 +
+
CP1 - -
GND
CPT0MX
CPT1MX
Figure 8.4. Comparator Input Multiplexer Block Diagram
Rev. 1.4
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