Hysteresis - Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual

25.3.4 Hysteresis

When the hysteresis level is set to a non-zero value, the digital output will not toggle until the positive input voltage is at a voltage equal
to the hysteresis level above or below the negative input voltage (see
to avoid continual comparator output changes due to noise when the positive and negative inputs are nearly equal by requiring the input
difference to exceed the hysteresis threshold.
In the analog comparator, hysteresis can be configured to 8 different levels. Level 0 is no hysteresis. Hysteresis is configured through
the HYST field in ACMPn_HYSTERESIS0 and ACMPn_HYSTERESIS1 registers. The hysteresis value can be positive or negative.
The comparator will output a 1 if:
There are two hysteresis registers, ACMPn_HYSTERESIS0 and ACMPn_HYSTERESIS1, as the ACMP supports asymmetric hystere-
sis. ACMPn_HYSTERESIS0 are the hysteresis values used when the comparator output is 0; ACMPn_HYSTERESIS1 are the values
used when the comparator output is 1. The user must set both registers to the same values if symmetric hysteresis is desired.
Along with the HYST field, the ACMPn_HYSTERESIS0/1 registers include the DIVVA and DIVVB fields. This allows the user to imple-
ment even larger hysteresis when comparing against VADIV or VBDIV, as the reference voltage can vary with the comparator output,
also.
Voltage
NEGSEL + HYST0
NEGSEL
NEGSEL + HYST1
CMPOUT without
Hysteresis
CMPOUT with
Hysteresis
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POSSEL - NEGSEL > HYST
HYSTERESIS0 HYSTERESIS1
Active Active
Figure 25.3. Hysteresis
Figure 25.3 Hysteresis on page 816
HYSTERESIS0
Active
POSSEL
Reference Manual
ACMP - Analog Comparator
). This feature can be used
HYSTERESIS1
Active
Time
Rev. 1.1 | 816