21. ACMP - Analog Comparator
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Quick Facts
What?
The ACMP (Analog Comparator) compares two ana-
log signals and returns a digital value telling which is
greater.
Why?
Applications often do not need to know the exact
value of an analog signal, only if it has passed a cer-
tain threshold. Often the voltage must be monitored
continuously, which requires extremely low power
consumption.
How?
Available down to Energy Mode 3 and using as little
as 100 nA, the ACMP can wake up the system when
input signals pass the threshold. The analog compa-
rator can compare two analog signals or one analog
signal and a highly configurable internal reference.
21.1 Introduction
The Analog Comparator compares the voltage of two analog inputs and outputs a digital signal indicating which input voltage is higher.
Inputs can either be from internal references or from external pins. Response time, and thereby the current consumption, can be config-
ured by altering the current supply to the comparator.
21.2 Features
• Up to 144 selectable external I/O inputs for both positive and negative inputs
• Up to 48 I/O can be used as a dividable reference
• Voltage supply monitoring
• Low power mode for internal V
DD
and bandgap references
• Selectable hysteresis
• 8 values
• Values can be positive or negative
• Divideable references have scale for both both output values, allowing for even larger hysteresis
• Selectable response time
• Asynchronous interrupt generation on selectable edges
• Rising edge
• Falling edge
• Both edges
• Operational in EM0 Active down to EM3 Stop
• Dedicated capacitive sense mode with up to 80 inputs
• Adjustable internal resistor
• Configurable output when inactive
• Comparator output direct on PRS
• Comparator output on GPIO through alternate functionality
• Output inversion available
EFM32JG1 Reference Manual
ACMP - Analog Comparator
silabs.com
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