NXP Semiconductors KE1xF Series, Reference Manual, Page: 876 / 1483

38.6.1 External pins
The CMP has two analog inputs: INP and INM. Each of these pins can accept an input
voltage that varies across the full operating range of the MCU. If the module is not
enabled, each pin can be used as a digital input or output. Consult the specific MCU
documentation to determine what functions are shared with these analog inputs.
The user can select either filtered or unfiltered comparator outputs for use on an external
I/O pad.
38.7 CMP functional modes
There are three main sub-blocks to the CMP module:
• The comparator itself
• The window function
• The filter function
The filter, C0[FILTER_CNT], can be clocked from an internal or external clock source.
The filter is programmable with respect to the number of samples that must agree before
a change in the output is registered. In the simplest case, only one sample must agree. In
this case, the filter acts as a simple sampler.
The external sample input is enabled using C0[SE]. When set, the output of the
comparator is sampled only on rising edges of the sample input.
The "windowing mode" is enabled by setting C0[WE]. When set, the comparator output
is sampled only when WINDOW=1. This feature can be used to ignore the comparator
output during time periods in which the input voltages are not valid. This is especially
useful when implementing zero-crossing-detection for certain PWM applications.
The comparator filter and sampling features can be combined as shown in the following
table. Individual modes are discussed below.
Table 38-3. Comparator sample/filter controls
Mode # C0[EN] C0[WE] C0[SE]
C0[FILTER_CN
T]
C0[FPR] Operation
1 0 X X X X Disabled
See the Disabled mode (# 1) .
2A 1 0 0 0x00 X Continuous Mode
Table continues on the next page...
CMP functional modes
Kinetis KE1xF Sub-Family Reference Manual, Rev. 4, 06/2019
876 NXP Semiconductors