Information

CMPx_MUXCR field descriptions (continued)
Field Description
NOTE: When an inappropriate operation selects the same input for both muxes, the comparator
automatically shuts down to prevent itself from becoming a noise generator.
000 IN0
001 IN1
010 IN2
011 IN3
100 IN4
101 IN5
110 IN6
111 IN7
2–0
MSEL
Minus Input Mux Control
Determines which input is selected for the minus input of the comparator. For INx inputs, see CMP, DAC,
and ANMUX block diagrams.
NOTE: When an inappropriate operation selects the same input for both muxes, the comparator
automatically shuts down to prevent itself from becoming a noise generator.
000 IN0
001 IN1
010 IN2
011 IN3
100 IN4
101 IN5
110 IN6
111 IN7
32.8 CMP functional description
The CMP module can be used to compare two analog input voltages applied to INP and
INM. CMPO is high when the non-inverting input is greater than the inverting input, and
is low when the non-inverting input is less than the inverting input. This signal can be
selectively inverted by setting CR1[INV] = 1.
SCR[IER] and SCR[IEF] are used to select the condition which will cause the CMP
module to assert an interrupt to the processor. SCR[CFF] is set on a falling-edge and
SCR[CFR] is set on rising-edge of the comparator output. The optionally filtered CMPO
can be read directly through SCR[COUT].
32.8.1 CMP functional modes
There are three main sub-blocks to the CMP module:
CMP functional description
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
644 Freescale Semiconductor, Inc.