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STM32F334x4 STM32F334x6 STM32F334x8 Functional overview

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 electrode 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.

Table 10. Capacitive sensing GPIOs available on STM32F334x4/6/8 devices

Group

Capacitive sensing

group name

Pin name - Group

Capacitive sensing

group name

Pin name

TSC_G1_IO1 PA0 -

TSC_G4_IO1 PA9

TSC_G1_IO2 PA1 - TSC_G4_IO2 PA10

TSC_G1_IO3 PA2 - TSC_G4_IO3 PA13

TSC_G1_IO4 PA3 - TSC_G4_IO4 PA14

TSC_G2_IO1 PA4 -

TSC_G5_IO1 PB3

TSC_G2_IO2 PA5 - TSC_G5_IO2 PB4

TSC_G2_IO3 PA6 - TSC_G5_IO3 PB6

TSC_G2_IO4 PA7 - TSC_G5_IO4 PB7

TSC_G3_IO1 PC5 -

TSC_G6_IO1 PB11

TSC_G3_IO2 PB0 - TSC_G6_IO2 PB12

TSC_G3_IO3 PB1 - TSC_G6_IO3 PB13

TSC_G3_IO1 PC5 - TSC_G6_IO4 PB14

----- -

Table 11. No. of capacitive sensing channels available on STM32F334x4/6/8 devices

Analog I/O group

Number of capacitive sensing channels

STM32F334xRx STM32F334xCx STM32F334xKx

G1 3 3 3

G2 3 3 3

G3 3 2 2

G4 3 3 3

G5 3 3 3

G6 3 3 0

Number of capacitive

sensing channels

18 17 14

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