Functional overview STM32F072x8 STM32F072xB
Both comparators can wake up from STOP mode, generate interrupts and breaks for the timers and can be also combined into a window comparator.
3.13 Touch sensing controller (TSC)
The STM32F072x8/xB devices provide a simple solution for adding capacitive sensing functionality to any application. These devices offer up to 24 capacitive sensing channels distributed over 8 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 in 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.
For operation, one capacitive sensing GPIO in each group is connected to an external capacitor and cannot be used as effective touch sensing channel.
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.
Table 5. Capacitive sensing GPIOs available on STM32F072x8/xB devices
Group
Capacitive sensing signal name
Pin name
Group
Capacitive sensing signal name
Pin name
1
2
3
4
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_IO1
TSC_G3_IO2
TSC_G3_IO3
TSC_G3_IO4
TSC_G4_IO1
TSC_G4_IO2
TSC_G4_IO3
TSC_G4_IO4
PC5
PB0
PB1
PB2
PA9
PA10
PA11
PA12
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
5
6
7
8
TSC_G5_IO1
TSC_G5_IO2
TSC_G5_IO3
TSC_G5_IO4
TSC_G6_IO1
TSC_G6_IO2
TSC_G6_IO3
TSC_G6_IO4
TSC_G7_IO1
TSC_G7_IO2
TSC_G7_IO3
TSC_G7_IO4
TSC_G8_IO1
TSC_G8_IO2
TSC_G8_IO3
TSC_G8_IO4
PE2
PE3
PE4
PE5
PD12
PD13
PD14
PD15
PB3
PB4
PB6
PB7
PB11
PB12
PB13
PB14
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