STMicroelectronics STM32F05 series - TSC Functional Description; TSC Block Diagram; Surface Charge Transfer Acquisition Overview; Figure 284. TSC Block Diagram

Touch sensing controller (TSC) RM0091
682/742 Doc ID 018940 Rev 1
27.3 TSC functional description
27.3.1 TSC block diagram
The block diagram of the touch sensing controller is shown in Figure 284: TSC block
diagram.
Figure 284. TSC block diagram
27.3.2 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 285). 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.
G1_IO1
G1_IO2
G1_IO3
G1_IO4
G2_IO1
G2_IO2
G2_IO3
G2_IO4
Gx_IO1
Gx_IO2
Gx_IO3
Gx_IO4
I/O Control
Logic
SYNC
Pulse generator
Spread Spectrum
TSC_IOG1CR
TSC_IOG2CR
TSC_IOGxCR
f
HCLK
Clock
prescalers
Group counters