Sensor Interaction - Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual

28.3.4 Sensor Interaction

Many sensor types require some type of excitation in order to work. The LESENSE module can generate a variety of sensor stimuli,
both on the same pin as the measurement is to be made on, as well as alternative pins.
By default, excitation is performed on the pin associated with the channel (i.e., excitation and sensor measurement is performed on the
same pin). The mode of the pin during the excitation phase is configured by the EXMODE bitfield in CHx_INTERACT. The available
modes during the excite phase are:
• DISABLED: The pin is disabled.
• HIGH: The pin is driven high.
• LOW: The pin is driven low.
• DACOUT: The pin is connected to the output of a VDAC channel.
Note:
Excitation with VDAC output is only available on some channels. Refer to
If the VDAC is in opamp-mode, setting EXMODE to DACOUT will result in excitation with output from the opamp.
LESENSE is able to perform sensor excitation on a pin other than the one being measured. When ALTEX in CHx_INTERACT is set,
the excitation will occur on the alternative excite pin associated with the given channel. By default, the alternative excite pins are map-
ped to the LES_ALTEX pins, but they can also be mapped to LESENSE CH
ured in ALTEXMAP in the CTRL register.
tation pins for different configurations.
LESENSE channel
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Figure 28.6 Pin Sequencing on page 938
excite pin.
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Table 28.2 LESENSE Excitation Pin Mapping on page 937
Table 28.2. LESENSE Excitation Pin Mapping
ALTEX = 0
LES_CH0
LES_CH1
LES_CH2
LES_CH3
LES_CH4
LES_CH5
LES_CH6
LES_CH7
LES_CH8
LES_CH9
LES_CH10
LES_CH11
LES_CH12
LES_CH13
LES_CH14
LES_CH15
illustrates the sequencing of the pin associated with the active channel and its alternative
LESENSE - Low Energy Sensor Interface
28.3.9 VDAC Interface
. Mapping of the alternative excite pins is config-
X+8 mod 16
ALTEXMAP = CH
LES_CH8
LES_CH9
LES_CH10
LES_CH11
LES_CH12
LES_CH13
LES_CH14
LES_CH15
LES_CH0
LES_CH1
LES_CH2
LES_CH3
LES_CH4
LES_CH5
LES_CH6
LES_CH7
Reference Manual
for details.
summarizes the mapping of exci-
ALTEX = 1
ALTEXMAP = ALTEX
LES_ALTEX0
LES_ALTEX1
LES_ALTEX2
LES_ALTEX3
LES_ALTEX4
LES_ALTEX5
LES_ALTEX6
LES_ALTEX7
LES_ALTEX0
LES_ALTEX1
LES_ALTEX2
LES_ALTEX3
LES_ALTEX4
LES_ALTEX5
LES_ALTEX6
LES_ALTEX7
Rev. 1.1 | 937