AT42QT2161-MMU Atmel, AT42QT2161-MMU Datasheet - Page 7

• Manufacturer Part Number: AT42QT2161-MMU
• Description: IC TOUCH SENSOR 16KEY QFN M-MOD
• Manufacturer: Atmel
• Type: Capacitiver

Specifications of AT42QT2161-MMU

• Touch Panel Interface: 8, 2-Wire
• Number Of Inputs/keys: 16 Key, Slider
• Resolution (bits): 10 b
• Data Interface: I²C, Serial
• Voltage Reference: Internal
• Voltage - Supply: 1.8 V ~ 5.5 V
• Current - Supply: 1.14mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3. Hardware and Functional
3.1
9614A–AT42–08/10
Matrix Scan Sequence
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 3-1.
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 3.2 on page
Key Numbers
X6
14
6
X5
13
5
Table 3-1
8); this can be set on a per-key basis. A burst is completed
X4
12
4
shows the key numbering.
X3
11
3
X2
10
2
X1
1
9
AT42QT2161
X0
0
8
Key numbers
7