
Electrode
Voltage
Time
Electrode Capacitor Charging and
Discharging with constant current
Hysteresis
Voltage Delta
Figure 49-3. TSI electrode oscillator chart
The oscillator frequency is give by the following equation
F
elec
I
2 * C
elec
*
Δ
V
Equation 4. TSI electrode oscillator frequency
Where:
I: constant current
C
elec
: electrode capacitance
Δ
V: Hysteresis delta voltage
So by this equation, for example, an electrode with C
elec
= 20 pF, with a current source of
I = 16 µA and
Δ
V = 600 m V have the following oscillation frequency:
F
elec
16 µA
2 * 20pF
*
600mV 0.67MHz
Equation 5. TSI electrode oscillator frequency
The current source is used to accommodate the TSI electrode oscillator frequency with
different electrode capacitance sizes.
49.4.1.2 Electrode oscillator and counter module control
The TSI oscillator frequency signal goes through a prescaler defined by the GENCS[PS]
and then enters in a modulus counter. GENCS[NSCN] defines the maximum count value
of the modulus counter.
Chapter 49 Touch Sensing Input (TSI)
K32 L2A Reference Manual, Rev. 2, 01/2020
NXP Semiconductors
1275
Содержание K32 L2A Series
Страница 2: ...K32 L2A Reference Manual Rev 2 01 2020 2 NXP Semiconductors...
Страница 42: ...K32 L2A Reference Manual Rev 2 01 2020 42 NXP Semiconductors...
Страница 122: ...Flash Memory Clock K32 L2A Reference Manual Rev 2 01 2020 122 NXP Semiconductors...
Страница 146: ...Module operation in low power modes K32 L2A Reference Manual Rev 2 01 2020 146 NXP Semiconductors...
Страница 158: ...Debug and security K32 L2A Reference Manual Rev 2 01 2020 158 NXP Semiconductors...
Страница 174: ...Module Signal Description Tables K32 L2A Reference Manual Rev 2 01 2020 174 NXP Semiconductors...
Страница 246: ...Application information K32 L2A Reference Manual Rev 2 01 2020 246 NXP Semiconductors...
Страница 322: ...Kinetis Bootloader Status Error Codes K32 L2A Reference Manual Rev 2 01 2020 322 NXP Semiconductors...
Страница 344: ...Application initialization information K32 L2A Reference Manual Rev 2 01 2020 344 NXP Semiconductors...
Страница 374: ...CMP Trigger Mode K32 L2A Reference Manual Rev 2 01 2020 374 NXP Semiconductors...
Страница 384: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 384 NXP Semiconductors...
Страница 592: ...Application Information K32 L2A Reference Manual Rev 2 01 2020 592 NXP Semiconductors...
Страница 602: ...Initialization and application information K32 L2A Reference Manual Rev 2 01 2020 602 NXP Semiconductors...
Страница 656: ...Functional Description K32 L2A Reference Manual Rev 2 01 2020 656 NXP Semiconductors...
Страница 664: ...Functional Description K32 L2A Reference Manual Rev 2 01 2020 664 NXP Semiconductors...
Страница 744: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 744 NXP Semiconductors...
Страница 762: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 762 NXP Semiconductors...
Страница 806: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 806 NXP Semiconductors...
Страница 868: ...Integer square root K32 L2A Reference Manual Rev 2 01 2020 868 NXP Semiconductors...
Страница 976: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 976 NXP Semiconductors...
Страница 1012: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1012 NXP Semiconductors...
Страница 1094: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1094 NXP Semiconductors...
Страница 1132: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1132 NXP Semiconductors...
Страница 1182: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1182 NXP Semiconductors...
Страница 1290: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1290 NXP Semiconductors...
Страница 1344: ...USB Voltage Regulator Module Signal Descriptions K32 L2A Reference Manual Rev 2 01 2020 1344 NXP Semiconductors...
Страница 1356: ...Initialization Application Information K32 L2A Reference Manual Rev 2 01 2020 1356 NXP Semiconductors...