ST STM32L4+ Series Reference Manual page 1046

Touch sensing controller (TSC)
31.3 TSC functional description
31.3.1 TSC block diagram
The block diagram of the touch sensing controller is shown in
diagram.
f
HCLK
31.3.2 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
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
I/O per analog I/O group must be enabled at a time.
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Figure 241. TSC block diagram
Pulse generator
Clock
prescalers
Spread spectrum
Group counters
TSC_IOG1CR
TSC_IOG2CR
TSC_IOGxCR
Figure
RM0432 Rev 6
242). Several analog I/O groups are available to allow
S
Figure 241: TSC block
SYNC
G1_IO1
G1_IO2
G1_IO3
G1_IO4
G2_IO1
G2_IO2
I/O control
G2_IO3
logic
G2_IO4
Gx_IO1
Gx_IO2
Gx_IO3
Gx_IO4
. Only one sampling capacitor
RM0432
MS30929V1