EFM32WG Datasheet, PDF (617/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

25.3 Functional description
...the world's most energy friendly microcontrollers
LESENSE is a module 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, for
measurement of sensor signals. LESENSE can also control the DAC to generate accurate reference
voltages. Figure 25.1 (p. 617) shows an overview of the LESENSE module. LESENSE consists
of a sequencer, count and compare block, a decoder, and a RAM block used for configuration and
result storage. The sequencer handles interaction with other peripherals as well as timing of sensor
measurements. The count and compare block is used to count pulses from ACMP outputs before
comparing with a configurable threshold. To autonomously analyze sensor results, the LESENSE
decoder provides possibility to define a finite state machine with up to 16 states, and programmable
actions upon state transitions. This allows the decoder to implement a wide range of decoding schemes,
for instance 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.
Figure 25.1. LESENSE block diagram
ACMP1 _CHn
ACMP1
POSSEL
* LESENSE cont rols CONVMODE and
OUTMODE individually for t he DAC
channels
Regist er bit fields
overridden by LESENSE
LESENSE
D AC0 _CH1
VSS
D AC0 _CH0
D AC0 _CH1
1.25 V
2.5 V
VDD
ACMP0 _CHn
ACMP0
Scaler
VDDLEVEL
POSSEL
ACMP1 INV
ACMP sam ple reg
Count er
Com pare
PRS input
Decoder
PRS
ACMP0 INV
DAC
interface
Se q u e n c e r
RAM
D AC0 _CH0
VSS
D AC0 _CH0
D AC0 _CH1
1.25 V
2.5 V
VDD
D AC0 _CH0
D AC0 _CH1
Scaler
LES_ALTEXn
DAC0
VDDLEVEL
CH0 CH1
CONVMODE*
OUTMODE*
CHx D ATA
CHx CTRL_EN
AUXHFRCO
25.3.1 Channel configuration
LESENSE has 16 individually configurable channels, the first eight are mapped to the channels of
ACMP0, while the last eight are mapped to the channels of ACMP1. Each LESENSE channel has
its own set of configuration registers. Channel configuration is split into three registers; CHx_TIMING,
CHx_INTERACT, and CHx_EVAL. Individual timing for each sensor is configured in CHx_TIMING,
sensor interaction is configured in CHx_INTERACT, and configurations regarding evaluation of the
measurements are done in CHx_EVAL. For improved readability, CHx_CONF will be used to address
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
617
www.energymicro.com