Touch sensing controller (TSC) RM0351
692/1693 DocID024597 Rev 3
23.3 TSC functional description
23.3.1 TSC block diagram
The block diagram of the touch sensing controller is shown in Figure 165: TSC block
diagram.
Figure 165. TSC block diagram
23.3.2 Surface charge transfer acquisition overview
The surface charge transfer acquisition is a proven, robust and efficient way to measure a
capacitance. It uses a minimum number of external components to operate with a single
ended electrode type. This acquisition is designed around an analog I/O group which is
composed of four GPIOs (see Figure 166). Several analog I/O groups are available to allow
the acquisition of several capacitive sensing channels simultaneously and to support a
larger number of capacitive sensing channels. Within a same analog I/O group, the
acquisition of the capacitive sensing channels is sequential.
One of the GPIOs is dedicated to the sampling capacitor C
S
. Only one sampling capacitor
I/O per analog I/O group must be enabled at a time.
-36
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