NXP Semiconductors K32 L2A Series, Reference Manual, Page: 1279 / 1379

Table 49-3. Delta voltage configuration (continued)
DVOLT V
p
(V) V
m
(V)
Δ
V (V)
01 1.111 0.519 0.592
10 0.986 0.644 0.342
11 0.914 0.716 0.198
49.4.8 Current source
The TSI module supports eight different current source power to increment from 500 nA
to 64 µA. TSI_GENCS[EXTCHRG] determines the current of electrode oscillator that
charges and discharges external electrodes. The TSI_GENCS[REFCHRG] determines the
current of reference oscillator on which the internal reference clock depends. The lower
current source takes more time for charge and discharge, which is useful to detect high-
accuracy change. The higher current source takes less time, which can be used to charge
a big electrode by less power consumption.
TSI_GENCS[CURSW] allows the current source to swap, so that the reference oscillator
and electrode oscillator use the opposite current sources. When TSI_GENCS[CURSW] is
set and the current sources are swapped, TSI_GENCS[EXTCHRG] and
TSI_GENCS[REFCHRG] still control the corresponding current sources, that is,
TSI_GENCS[EXTCHRG] controls the reference oscillator current and
TSI_GENCS[REFCHRG] controls the electrode oscillator current.
49.4.9 End of scan
As a scan starts, [SCNIP] bit is set to indicate scan is in progress. When the scan
completes, the [EOSF] bit is set. Before clearing the [EOSF] bit, the value in
TSI_DATA[TSICNT] must be read. If the TSI_GENCS[TSIIEN] and
TSI_GENCS[ESOR] are set andTSI_GENCS[DMAEN]is not set, an interrupt is
submitted to CPU for post-processing immediately. The interrupt is also optional to wake
MCU to execute ISR if it is in low power mode. When DMA function is enabled by
setting TSI_GENCS[TSIIEN] and TSI_GENCS[ESOR], as soon as scan completes, a
DMA transfer request is asserted to DMA controller for data movement, generally, DMA
engine will fetch TSI conversion result from TSI_DATA register,store it to other memory
space and then refresh the TSI scan channel index(TSI_DATA[TSICH]) for next loop.
When DMA transfer is done, TSI_GENCS[EOSF] is cleared automatically.
Chapter 49 Touch Sensing Input (TSI)
K32 L2A Reference Manual, Rev. 2, 01/2020
NXP Semiconductors 1279