Information

• Compensate temperature and supply voltage variations
• Stand alone operation not requiring any external crystal even in low power modes
• Configurable integration of each electrode capacitance measurement from 1 to 4096
periods
• Programmable Electrode Oscillator and TSI Reference Oscillator allowing high
sensitivity, small scan time and low power functionality.
• Only uses one pin per electrode implementation with no external hardware required
48.3 Overview
This section presents an overview of the TSI module. The following figure presents the
simplified TSI module block diagram.
External
Electrodes
Cap Switch
PAD0
PAD1
PAD15
Capacitance Measurement Unit
NSCN PS EXTCHRG REFCHRG
TSICHnCNT
STPE
STM
Electrode
Scan Unit
EOSF
PEN [15:0]
OVRF
SMOD
LPSCNITV
Touch
Detection
Unit
TSICHLTH
TSICHHTH
EXTERF
OUTRGF
Touch Sensing Input (TSI) Module
Figure 48-1. Touch sensing input block diagram
Overview
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
1188 Freescale Semiconductor, Inc.