...the world's most energy friendly microcontrollers
2014-07-02 - Tiny Gecko Family - d0034_Rev1.20
336
www.silabs.com
21.3.4 Sensor interaction
Many sensor types require some type of excitation in order to work. LESENSE can generate a variety
of sensor stimuli, both on the same pin as the measurement is to be made on, and on 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 in EXMODE 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 DAC channel.
Note
Excitation with DAC output is only available on channels 0, 1, 2, and 3 (DAC0_CH0) and
channels 12, 13, 14, and 15 (DAC0_CH1).
If the DAC 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 another pin than the one to be measured. When
ALTEX in CHx_INTERACT is set, the excitation will occur on the alternative excite pin associated with
the given channel. All LESENSE channels mapped to ACMP0 have their alternative channel mapped
to the corresponding channel on ACMP1, and vice versa. Alternatively, the alternative excite pins can
be routed to the LES_ALTEX pins. Mapping of the alternative excite pins is configured in ALTEXMAP
in CTRL. Table 21.2 (p. 336) summarizes the mapping of excitation pins for different configurations.
Table 21.2. LESENSE excitation pin mapping
ALTEX = 0
ALTEX = 1
LESENSE channel
ALTEXMAP = ACMP
ALTEXMAP = ALTEX
0
ACMP0_CH0
ACMP1_CH0
LES_ALTEX0
1
ACMP0_CH1
ACMP1_CH1
LES_ALTEX1
2
ACMP0_CH2
ACMP1_CH2
LES_ALTEX2
3
ACMP0_CH3
ACMP1_CH3
LES_ALTEX3
4
ACMP0_CH4
ACMP1_CH4
LES_ALTEX4
5
ACMP0_CH5
ACMP1_CH5
LES_ALTEX5
6
ACMP0_CH6
ACMP1_CH6
LES_ALTEX6
7
ACMP0_CH7
ACMP1_CH7
LES_ALTEX7
8
ACMP1_CH0
ACMP0_CH0
LES_ALTEX0
9
ACMP1_CH1
ACMP0_CH1
LES_ALTEX1
10
ACMP1_CH2
ACMP0_CH2
LES_ALTEX2
11
ACMP1_CH3
ACMP0_CH3
LES_ALTEX3
12
ACMP1_CH4
ACMP0_CH4
LES_ALTEX4
13
ACMP1_CH5
ACMP0_CH5
LES_ALTEX5
14
ACMP1_CH6
ACMP0_CH6
LES_ALTEX6
15
ACMP1_CH7
ACMP0_CH7
LES_ALTEX7
Summary of Contents for EFM32TG
Page 543: ......