DocID025202 Rev 7
438/1080
RM0365
Touch sensing controller (TSC)
455
19.3
TSC functional description
19.3.1 TSC
block
diagram
The block diagram of the touch sensing controller is shown in
.
Figure 127. TSC block diagram
19.3.2
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
). 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
'?)/
'?)/
'?)/
'?)/
'?)/
'?)/
'?)/
'?)/
'X?)/
'X?)/
'X?)/
'X?)/
)/CONTROL
LOGIC
39.#
0ULSEGENERATOR
3PREADSPECTRUM
43#?)/'#2
43#?)/'#2
43#?)/'X#2
F
(#,+
#LOCK
PRESCALERS
'ROUPCOUNTERS