Atmel Evaluation Kit AT91SAM9X35-EK AT91SAM9X35-EK Data Sheet
Product codes
AT91SAM9X35-EK
937
SAM9X35 [DATASHEET]
11055E–ATARM–10-Mar-2014
Figure 42-9. Touchscreen Switches Implementation
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
“ADC Touchscreen Mode Register”
“ADC Touchscreen Mode Register”
. 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 “ADC
Touchscreen Mode Register”
Touchscreen Mode Register”
. 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.
U
L
U
R
L
R
VDDANA
L
L
VDDANA
GND
To the ADC
VDDANA
GND
SENSE
U
L
U
R
L
L
L
R
VDDANA
GND
VDDANA for Ypos
GND for Xpos
VDDANA for Xpos
GND for Ypos
Sense
GND
0
1
2
3
4