at42qt2160 ATMEL Corporation, at42qt2160 Datasheet - Page 4

• Manufacturer Part Number: at42qt2160
• Description: Qslide?, 16-key Qmatrix? Sensor Ic
• Manufacturer: ATMEL Corporation

3.1
3.2
4. Hardware and Functional
4.1
4
Keys and Slider
Enabling/Disabling Keys
Matrix Scan Sequence
AT42QT2160
Figure 3-1.
The QT2160 is capable of a maximum of 16 keys. These can be located anywhere within an
electrical grid of 8X and 2Y scan lines.
A lesser number of enabled keys will cause any unused acquisition burst timeslots to be pared
from the sampling sequence, to optimize acquire speed and lessen power consumption. Thus, if
only 8 keys are actually enabled, only 8 timeslots are used for scanning.
Additional processing can be done on the keys to form a slider. The slider will have to start at X0
and use only Y0. The slider can consist of a minimum of 2 keys and a maximum of 8 keys.
Keys can be enabled by setting a nonzero burst length. A zero burst length disables the key.
The circuit operates by scanning each key sequentially, key by key. Key scanning begins with
location X = 0, Y = 0 (key 0). X axis keys are known as rows while Y axis keys are referred to as
columns although this has no reflection on actual wiring. Keys are scanned sequentially by row,
for example the sequence X0Y0 X1Y0...X7Y0, X0Y1, X1Y1... etc. Keys are also numbered from
0...15. Key 0 is located at X0Y0.
Table 4-1.
Each key is sampled in a burst of acquisition pulses whose length is determined by the Setups
parameter BL
entirely before the next key is sampled; at the end of each burst the resulting signal is converted
to digital form and processed. The burst length directly impacts key gain; each key can have a
unique burst length in order to allow tailoring of key sensitivity on a key-by-key basis.
Y0
Y1
X7
15
7
(Section 4.2 on page
Field Flow Between X and Y Elements
Key Numbers
X6
14
6
X5
13
5
Table 4-1
5); this can be set on a per-key basis. A burst is completed
element
X4
12
4
shows the key numbering.
X
X3
11
3
X2
10
2
overlying panel
elem ent
Y
X1
1
9
X0
0
8
9502A–AT42–07/08
Key numbers