Vbat; Touch Sensing Controller (Tsc); Table 5. Capacitive Sensing Gpios Available On Stm32F042X Devices - STMicroelectronics STM32F042G4 Manual

Functional overview
3.10.3 V battery voltage monitoring
BAT
This embedded hardware feature allows the application to measure the V
using the internal ADC channel ADC_IN18. As the V
and thus outside the ADC input range, the V
divider by 2. As a consequence, the converted digital value is half the V
3.11

Touch sensing controller (TSC)

The STM32F042x devices provide a simple solution for adding capacitive sensing
functionality to any application. These devices offer up to 14 capacitive sensing channels
distributed over 5 analog I/O groups.
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. To limit the CPU bandwidth usage, this acquisition is directly managed by the
hardware touch sensing controller and only requires few external components to operate.
The touch sensing controller is fully supported by the STMTouch touch sensing firmware
library, which is free to use and allows touch sensing functionality to be implemented reliably
in the end application.
Group
1
2
3
20/117

Table 5. Capacitive sensing GPIOs available on STM32F042x devices

Capacitive sensing
signal name
TSC_G1_IO1
TSC_G1_IO2
TSC_G1_IO3
TSC_G1_IO4
TSC_G2_IO1
TSC_G2_IO2
TSC_G2_IO3
TSC_G2_IO4
TSC_G3_IO2
TSC_G3_IO3
TSC_G3_IO4
pin is internally connected to a bridge
BAT
Pin
Group
name
PA0
PA1
4
PA2
PA3
PA4
PA5
5
PA6
PA7
PB0
PB1
PB2
DocID025832 Rev 2
BAT
voltage may be higher than V
BAT
BAT
Capacitive sensing
signal name
TSC_G4_IO1
TSC_G4_IO2
TSC_G4_IO3
TSC_G4_IO4
TSC_G5_IO1
TSC_G5_IO2
TSC_G5_IO3
TSC_G5_IO4
STM32F042xx
battery voltage
,
DDA
voltage.
Pin
name
PA9
PA10
PA11
PA12
PB3
PB4
PB6
PB7