Техническая Спецификация для Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK
Модели
AT91SAM9N12-EK
875
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
42.7.7 Sequence
and Noise Filtering
The ADC Controller can manage ADC conversions and Touchscreen measurement. On each trigger event the sequence
of ADC conversions is performed as described in
of ADC conversions is performed as described in
Touchscreen measure frequency can be specified in number of trigger events by writing the TSFREQ parameter in the
. An internal counter counts triggers up to TSFREQ, and every time it rolls out, a
Touchscreen sequence is appended to the classic ADC conversion sequence (see
Additionally the user can average multiple Touchscreen measures by writing the TSAV parameter in the
. This can be 1, 2, 4 or 8 measures performed on consecutive triggers as illustrated in
bellow. Consequently, the TSFREQ parameter must be greater or equal to the TSAV parameter.
Figure 42-11. Insertion of Touchscreen sequences (TSFREQ = 2; TSAV = 1)
42.7.8 Measured Values, Registers and Flags
As soon as the controller finishes the Touchscreen sequence, XRDY, YRDY and PRDY are set and can generate an
interrupt. These flags can be read in the
interrupt. These flags can be read in the
. They are reset independently by reading in
ADC_XPOSR, ADC_YPOSR and ADC_PRESSR. for classic ADC conversions.
presents XPOS (V
X
- V
Xmin
) on its LSB and XSCALE (V
XMAX
- V
Xmin
) aligned
on the 16th bit.
presents YPOS (V
Y
- V
Ymin
) on its LSB and YSCALE (V
YMAX
- V
Ymin
) aligned
on the 16th bit.
To improve the quality of the measure, the user must calculate: XPOS/XSCALE and YPOS/YSCALE.
V
XMAX,
V
Xmin,
V
YMAX,
and
V
Ymin
are measured at the first start up of the controller. These values can change during use, so
it can be necessary to refresh them. Refresh can be done by writing ‘1’ in the CALIB field of the control register
(ADC_CR).
(ADC_CR).
presents Z1 on its LSB and Z2 aligned on the 16th bit. See
to
know how use them.
Trigger event
ADC_SEL
XRDY
Read the
ADC_XPOSR
Read the
ADC_XPOSR
C
T
C
T
C
C
T
C
T
C
C
C: Classic ADC Conversion Sequence - T: Touchscreen Sequence
YRDY
Read the
ADC_YPOSR
Read the
ADC_YPOSR