28.2 Features
• Up to 16 sensors
• Autonomous sensor monitoring in EM0, EM1, and EM2
• Highly configurable decoding of sensor results
• Interrupt on sensor events
• Configurable enable signals to external sensors
• Circular buffer for storage of up to 16 sensor results
• Multiple evaluation modes minimize the need for software interaction
• Supports ADC0 sampling and evaluation
• Support for multiple sensor types
• LC sensors
• Capacitive sensing
• General analog sensors
28.3 Functional Description
The LESENSE module is capable of controlling on-chip peripherals in order to perform monitoring of different sensors with little or no
CPU intervention. LESENSE uses the analog comparators (ACMP) or ADC0 for measurement of sensor signals. LESENSE can also
control the VDAC to generate accurate reference voltages.
Figure 28.1 LESENSE Block Diagram on page 932
shows an overview of
the LESENSE module.
The LESENSE module consists of a sequencer, an evaluation block, a decoder, and a RAM block:
• The sequencer handles interaction with other peripherals and controls timing of sensor measurements. It also includes a counter
that can be used to count pulses on the ACMP output.
• The evaluation block is used to process the data collected by the sequencer.
• To autonomously analyze sensor results, the LESENSE decoder provides the ability to define a finite state machine with up to 32
states, as well as define programmable actions upon state transitions. This allows the decoder to implement a wide range of decod-
ing schemes, such as quadrature decoding.
• A RAM block is used for storage of configuration and measurement results. This allows LESENSE to have a relatively large result
buffer enabling the chip to remain in a low energy mode for long periods of time while collecting sensor data.
VDAC0
ADC0
LESENSE
ACMP1
ACMP0
Register bitfields
overridden by LESENSE
CH0
CH1
VDAC0_OUT0
VDAC0_OUT1
GND
VADIV
VBDIV
BUS1
BUS2
BUS3
BUS4
BUS0
-
+
APORT
VLP
POSSEL
EN
NEGSEL
VDAC0 Internal
Connections
GND
VADIV
VBDIV
BUS1
BUS2
BUS3
BUS4
BUS0
APORT
VLP
Dedicated
Dedicated
HYST0
DIVVA0
DIVVB0
HYST1
DIVVA1
DIVVB1
BIASPROG FULLBIAS
CSRESEN
CSRESSEL
PERCTRL_ACMP0INV
CURCH[3]
Saturating counter
ACMP sample register
ADC sample register
CH_INTERACT_SAMPLE
PERCTRL_ACMP1INV
Threshold compare
Sliding window
Step Detect
CH_EVAL_MODE
LESENSE
DECODER
SCANRES
SENSORSTATE
PRS input
SCANMASK
CHnDATA
CHnCTRL_EN
LES_CHn
LES_ALTEXn
OPAnOUT_PEN
CH_INTERACT_SAMPLE
VDAC0 Internal
Connections
Figure 28.1. LESENSE Block Diagram
Reference Manual
LESENSE - Low Energy Sensor Interface
silabs.com
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