GD32W51x User Manual
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26.
Touch sensing interface (TSI)
26.1.
Overview
Touch Sensing Interface (TSI) provides a convenient solution for touch keys, sliders and
capacitive proximity sensing applications. The controller builds on charge transfer method.
Placing a finger near fringing electric fields adds capacitance to the system and TSI is able to
measure this capacitance change using charge transfer method.
26.2.
Characteristics
Charge transfer sequence fully controlled by hardware.
3 fully parallel groups implemented.
9 IOs configurable for capacitive sensing Channel Pins and 3 for Sample Pins.
Configurable transfer sequence frequency.
Able to implement the user specific charge transfer sequences.
Sequence end and error flags / configurable interrupts.
Spread spectrum function implemented.
26.3.
Function Overview
26.3.1.
TSI block diagram
Figure 26-1. Block diagram of TSI module
TSI registers
A
H
B
B
u
s
Group 0 IO
Controller
Pulse Clock
Generators
Charge Transfer
Sequence FSM
Group 1 IO
Controller
Group 2 IO
Controller
TSI Counters
G1_IO0
G1_IO3
G1_IO2
G1_IO1
G2_IO0
G2_IO3
G2_IO2
G2_IO1
G0_IO0
G0_IO3
G0_IO2
G0_IO1
26.3.2.
Touch sensing technique overview
There are different technologies for touch sensing, such as optical, resistive, capacitive, strain,