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STM32L151xC/C-A STM32L152xC/C-A
Functional overview
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Both comparators can wake up from Stop mode, and be combined into a window
comparator.
The internal reference voltage is available externally via a low-power / low-current output
buffer (driving current capability of 1 µA typical).
3.14 System
configuration controller and routing interface
The system configuration controller provides the capability to remap some alternate
functions on different I/O ports.
The highly flexible routing interface allows the application firmware to control the routing of
different I/Os to the TIM2, TIM3 and TIM4 timer input captures. It also controls the routing of
internal analog signals to ADC1, COMP1 and COMP2 and the internal reference voltage
V
REFINT
.
3.15 Touch
sensing
The STM32L151xC/C-A and STM32L152xC/C-A devices provide a simple solution for
adding capacitive sensing functionality to any application. These devices offer up to 23
capacitive sensing channels distributed over 10 analog I/O groups. Both software and timer
capacitive sensing acquisition modes are supported.
Capacitive sensing technology is able to detect the presence of a finger near a sensor which
is protected from direct touch by a dielectric (glass, 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. It consists of
charging the sensor capacitance and then transferring a part of the accumulated charges
into a sampling capacitor until the voltage across this capacitor has reached a specific
threshold. The capacitive sensing acquisition only requires few external components to
operate. This acquisition is managed directly by the GPIOs, timers and analog I/O groups
(see
Section 3.14: System configuration controller and routing interface
Reliable touch sensing functionality can be quickly and easily implemented using the free
STM32L1xx STMTouch touch sensing firmware library.
3.16
Timers and watchdogs
The ultra-low-power STM32L151xC/C-A and STM32L152xC/C-A devices include seven
general-purpose timers, two basic timers, and two watchdog timers.
compares the features of the general-purpose and basic timers.
