ST STM32F301 6 Series Reference Manual page 314

Touch sensing controller (TSC)
16.3 TSC functional description
16.3.1 TSC block diagram
The block diagram of the touch sensing controller is shown in
f
HCLK
16.3.2 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 composed of
up to four GPIOs (see
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.
The remaining GPIOs are dedicated to the electrodes and are commonly called channels.
For some specific needs (such as proximity detection), it is possible to simultaneously
enable more than one channel per analog I/O group.
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Figure 87. TSC block diagram
Pulse generator
Clock
prescalers
Spread spectrum
Group counters
TSC_IOG1CR
TSC_IOG2CR
TSC_IOGxCR
Figure 88). Several analog I/O groups are available to allow the
RM0366 Rev 5
Figure 87.
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
S
RM0366
MS30929V1