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24.1.2 CMP input connections
The following table shows the fixed internal connections to the CMP0.
Table 24-1. CMP input connections
CMP inputs
CMP0
IN0
CMP0_IN0
IN1
CMP0_IN1
IN2
CMP0_IN2
IN3
CMP0_IN3
IN4
12-bit DAC0 reference/ CMP0_IN4
IN5
CMP0_IN5
IN6
IN7
6-bit DAC0 reference
1. This is the PMC bandgap 1V reference voltage. Prior to using as CMP input, ensure that you enable the bandgap buffer by
setting PMC_REGSC[BGBE]. See the device data sheet for the bandgap voltage (V
BG
) specification.
24.1.3 CMP external references
The 6-bit DAC sub-block supports selection of two references. For this device, the
references are connected as follows:
• VREF_OUT–V
in1
input. When using VREF_OUT, any ADC conversion using this
same reference at the same time is negatively impacted.
• VDD–V
in2
input
24.1.4 CMP trigger mode
The CMP and 6-bit DAC sub-block supports trigger mode operation when
CMP_CR1[TRIGM] is set. When trigger mode is enabled, the trigger event will initiate a
compare sequence that must first enable the CMP and DAC prior to performing a CMP
operation and capturing the output. In this device, control for this two-staged sequencing
is provided from the LPTMR. The LPTMR triggering output is always enabled when the
LPTMR is enabled. The first signal is supplied to enable the CMP and DAC and is
asserted at the same time as the TCF flag is set. The delay to the second signal that
triggers the CMP to capture the result of the compare operation is dependent on the
LPTMR configuration.
Chip-specific CMP information
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
392
Freescale Semiconductor, Inc.