Channel Configuration - Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual

28.3.1 Channel Configuration

LESENSE has 16 individually configurable channels, each with 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, sen-
sor 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 refer to the channel configuration registers (CHx_TIMING, CHx_INTERACT, and
CHx_EVAL) throughout this chapter.
By default, the channel configuration registers are directly mapped to the channel number. Configuring SCANCONF in CTRL makes it
possible to alter this mapping.
Configuring SCANCONF to INVMAP will make channels 0-7 use the channel configuration registers for channels 8-15, and vice versa.
This feature allows an application to quickly and easily switch the configuration set for the channels.
Setting SCANCONF to TOGGLE will make channel x alternate between using CH
is decided by the state of the corresponding bit in SCANRES. For instance, if channel 3 is performing a scan and bit 3 in SCANRES is
set, CH _CONF will be used. Channels 8 through 15 will toggle between CH
11
way to implement hysteresis on channel events, as threshold values can be changed depending on the sensor status.
Setting SCANCONF to DECDEF will make the state of the decoder define which scan configuration to be used. If the decoder state is
at index 16 or higher, channel x will use CH
CH _CONF when the decoder state index is less than 8 and CH
X
decoder state to define which configuration to use enables easy implementation of hysteresis, for example, as different threshold values
can be used for the same channel depending on the state of the application.
page 933 summarizes how channel configuration is selected for different settings of SCANCONF.
LESENSE
channel x
DIRMAP
0 <= x < 8 CH _CONF
x
8 <= x < 16 CH _CONF
x
Channels are enabled in the CHEN register, where bit x enables channel x. During a scan, all enabled channels are measured, starting
with the lowest indexed channel.
enabled.
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_CONF, otherwise it will use CH
X+8
Table 28.1. LESENSE Scan Configuration Selection
INVMAP
SCANRES[n] = 0
CH _CONF CH _CONF
x+8 x
CH _CONF CH _CONF
x-8 x
Figure 28.3 Scan Sequence on page 934
LESENSE - Low Energy Sensor Interface
_CONF and CH
X
_CONF and CH
X
_CONF. Similarly, channels 8 through 15 will use
X
_CONF when the decoder state index is higher than 7. Allowing the
X-8
Table 28.1 LESENSE Scan Configuration Selection on
SCANCONF
TOGGLE
SCANRES[n] = 1 DECSTATE < 16
CH _CONF CH
x+8
CH _CONF CH
x-8
illustrates a scan sequence with channels 3, 5, and 9
Reference Manual
_CONF. The configuration used
X+8
_CONF. This mode provides an easy
X-8
DECDEF
DECSTATE >= 16
_CONF CH _CONF
x x+8
_CONF CH _CONF
x x-8
Rev. 1.1 | 933