STM32WB55xx STM32WB35xx
Functional overview
3.15
Voltage reference buffer (VREFBUF)
The STM32WB55xx devices embed a voltage reference buffer that can be used as voltage
reference for the ADC and also as voltage reference for external components through the
VREF+ pin. The internal voltage reference buffer supports two voltages:
ï‚· 2.048 V
ï‚· 2.5 V
An external voltage reference can be provided through the VREF+ pin when the internal
voltage reference buffer is off. The VREF+ pin is double-bonded with VDDA on UFQFPN48
package, hence the internal voltage reference buffer is not available on a dedicated pin, but
user can still use the VDDA value.
3.16
Comparators (COMP)
The STM32WB55xx and STM32WB35xx devices embed two rail-to-rail comparators with
programmable reference voltage (internal or external), hysteresis and speed (low speed for
low-power) and with selectable output polarity.
The reference voltage can be one of the following:
ï‚· External I/O
ï‚· Internal reference voltage or submultiple (1/4, 1/2, 3/4).
All comparators can wake up from Stop mode, generate interrupts and breaks for the timers
and can be also combined into a window comparator.
3.17
Touch sensing controller (TSC)
The touch sensing controller provides a simple solution for adding capacitive sensing
functionality to any application. Capacitive sensing technology is able to detect finger
presence near an electrode which is protected from direct touch by a dielectric such as
glass or plastic. The capacitive variation introduced by the finger (or any conductive object)
is measured using a proven implementation based on a surface charge transfer acquisition
principle.
The touch sensing controller is fully supported by the STMTouch touch sensing firmware
library (free to use) and enables reliable touch sensing functionality in the end application.
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