ATMEL MXT224

Features
• maXTouch™ Touchscreen
•
•
•
•
•
•
•
•
•
•
•
•
– True 12-bit multi-touch with independent XY tracking for up to 10 concurrent
touches in real time with touch size reporting
– Up to 4.3 inch diagonal screen size supported with 10 mm “pinch” separation
– Up to 10.1 inch support with correspondingly wider “pinch”
Number of Channels
– Up to 224 (subject to other configuration limitations)
– Electrode grid configurations up to 20 X by 10 Y lines supported (subject to 30
total pins and a maximum of 14 Y lines)
maXTouch Touch Key Support
– Up to 32 channels can be allocated as fixed keys (subject to other configurations)
Zero Additional Part Count
– 16 X by 14 Y matrix (224 channels) implementable with power bypass capacitors only
Signal Processing
– Advanced digital filtering using both hardware engine and firmware
– Self-calibration
– Auto drift compensation
– Adjacent Key Suppression® (AKS™) technology
– Grip and face suppression
– Reports one-touch and two-touch gestures
– Down-scaling and clipping support to match LCD resolution
– Ultra-fast start-up and calibration for best user experience
– Supports axis flipping and axis switch-over for portrait and landscape modes
Scan Speed
– Maximum single touch >250Hz, subject to configuration
– Configurable to allow power/speed optimization
– Programmable timeout for automatic transition from active to idle states
Response Times
– Initial latency <10 ms for first touch from idle, subject to configuration
Sensors
– Works with PET or glass sensors
– Works with all proprietary sensor patterns recommended by Atmel®
– Works with passive stylus
Panel Thickness
– Glass up to 3 mm, screen size dependent
– Plastic up to 1.5 mm, screen size dependent
Interface
– I2C-compatible slave mode 400 kHz
Dual-rail Power
– Interface 1.8V to 3.3V nominal, analog 2.7V to 3.3V nominal
Power Consumption
– Idle 80Hz: <1.8 mW, subject to configuration
– One Touch Active 80Hz: 3.9 mW, subject to configuration
– Sleep: 4.5 µW
Package
– 49-ball UFBGA 5 x 5 x 0.6 mm, 0.65 ball pitch
– 49-ball VFBGA 5 x 5 x 1 mm, 0.65 ball pitch
– 48-pin QFN 6 x 6 x 0.6 mm, 0.4 mm pin pitch
maXTouch™
224-channel
Touchscreen
Sensor IC
mXT224
Summary
Note: This is a summary document.
A complete document is available
under NDA. For more information
contact www.atmel.com/touchscreen.
9530BS–AT42–10/09
1. Pinout and Schematic
1.1
1.1.1
Pinout Configuration
49-ball UFBGA/VFBGA
Top View
1
2
3
4
Bottom View
5
6
7
7
5
6
3
4
2
1
A
A
B
B
C
D
1.1.2
C
mXT224
QT602240
E
E
F
F
G
G
48-pin QFN
Y1
Y2
Y3
Y4
Y5
Y6
Y8
Y7
Y9
Y10
Y11
Y12
Y13
1
48 47 46 45 44 43 42 41 40 39 38 37
36
GND
2
35
GND
AVDD
3
34
AVDD
X8
4
33
X7
X9
5
32
X6
X10
6
X11
7
mXT224
Y0
31
X5
30
X4
X12
8
29
X3
X13
9
28
X2
X14
10
27
X1
X15
11
26
X0
GND
25
12
13 14 15 16 17 18 19 20 21 22 23 24
GND
CHG
ADDR_SEL
GPIO3/MOSI
GPIO2/SCK
VDD
GPIO1
GPIO0/SYNC
SCL
SDA
N/C
RESET
VDD
2
D
mXT224
9530BS–AT42–10/09
mXT224
1.2
Pinout Descriptions
1.2.1
49-ball UFBGA/VFBGA
Table 1-1.
Pin Listing
Ball
Name
Type
A1
AVDD
P
A2
Y12
I/O
Y line connection or X line in extended mode
Leave open
A3
Y10
I/O
Y line connection or X line in extended mode
Leave open
A4
Y8
I
Y line connection
Leave open
A5
Y6
I
Y line connection
Leave open
A6
Y4
I
Y line connection
Leave open
A7
Y2
I
Y line connection
Leave open
B1
X8
O
X matrix drive line
Leave open
B2
GND
P
Ground
B3
Y11
I/O
B4
Y9
B5
Comments
Analog power
If Unused, Connect To...
–
–
Y line connection or X line in extended mode
Leave open
I
Y line connection
Leave open
Y5
I
Y line connection
Leave open
B6
Y1
I
Y line connection
Leave open
B7
Y0
I
Y line connection
Leave open
C1
X10
O
X matrix drive line
Leave open
C2
X9
O
X matrix drive line
Leave open
C3
Y13
I/O
Y line connection or X line in extended mode
Leave open
C4
Y7
I
Y line connection
Leave open
C5
Y3
I
Y line connection
Leave open
C6
GND
P
Ground
–
C7
AVDD
P
Analog power
–
D1
X12
O
X matrix drive line
Leave open
D2
X13
O
X matrix drive line
Leave open
D3
X11
O
X matrix drive line
Leave open
D4
GND
P
Ground
D5
X7
O
X matrix drive line
Leave open
D6
X5
O
X matrix drive line
Leave open
D7
X6
O
X matrix drive line
Leave open
E1
X14
O
X matrix drive line
Leave open
E2
X15
O
X matrix drive line
Leave open
E3
RESET
I
Reset low; has internal 30 k to 60 k pull-up resistor
Leave open or Vdd
E4
GPIO1
I/O
General purpose I/O
Input: GND
Output: leave open
–
3
9530BS–AT42–10/09
Table 1-1.
I
O
P
4
Pin Listing (Continued)
Ball
Name
Type
Comments
E5
X1
O
X matrix drive line
Leave open
E6
X3
O
X matrix drive line
Leave open
E7
X4
O
X matrix drive line
Leave open
F1
VDD
P
Digital power
–
F2
GND
P
Ground
–
F3
SCL
OD
Serial Interface Clock
–
F4
GPIO3/
MOSI
I/O
General purpose I/O /
Debug data
Input: GND
Output: leave open
F5
GND
P
F6
CHG
OD
F7
X2
O
X matrix drive line
Leave open
G1
N/C
–
No connection
Leave open
G2
SDA
OD
Serial Interface Data
G3
GPIO0/
SYNC
I/O
General purpose I/O
External synchronization
Input: GND
Output: leave open
G4
GPIO2/
SCK
I/O
General purpose I/O /
Debug clock
Input: GND
Output: leave open
G5
VDD
P
Ground
–
State change interrupt
–
Digital power
2
G6
ADDR_SEL
I
I C-compatible address select
G7
X0
O
X matrix drive line
Input only
Output only, push-pull
Ground or power
If Unused, Connect To...
I/O
OD
–
–
–
Leave open
Input and output
Open drain output
mXT224
9530BS–AT42–10/09
mXT224
1.2.2
48-pin QFN
Table 1-2.
Pin Listing
Pin
Name
Type
1
Y13
I/O
2
GND
P
Ground
–
3
AVDD
P
Analog power
–
4
X8
O
X matrix drive line
Leave open
5
X9
O
X matrix drive line
Leave open
6
X10
O
X matrix drive line
Leave open
7
X11
O
X matrix drive line
Leave open
8
X12
O
X matrix drive line
Leave open
9
X13
O
X matrix drive line
Leave open
10
X14
O
X matrix drive line
Leave open
11
X15
O
X matrix drive line
Leave open
12
GND
P
Ground
–
13
VDD
P
Digital power
–
14
RESET
I
Reset low; has internal 30 k to 60 k pull-up resistor
15
N/C
–
No connection
16
SDA
OD
Serial Interface Data
–
17
SCL
OD
Serial Interface Clock
–
18
GPIO0/
SYNC
I/O
General purpose I/O
External synchronization
Input: GND
Output: leave open
19
GPIO1
I/O
General purpose I/O
Input: GND
Output: leave open
20
VDD
P
21
GPIO2/
SCK
I/O
General purpose I/O /
Debug clock
Input: GND
Output: leave open
22
GPIO3/
MOSI
I/O
General purpose I/O /
Debug data
Input: GND
Output: leave open
23
ADDR_SEL
I
24
CHG
OD
25
GND
26
Comments
Y line connection or X line in extended mode
Digital power
If Unused, Connect To...
Leave open
Leave open or Vdd
Leave open
–
I2C-compatible address select
–
State change interrupt
–
P
Ground
–
X0
O
X matrix drive line
Leave open
27
X1
O
X matrix drive line
Leave open
28
X2
O
X matrix drive line
Leave open
29
X3
O
X matrix drive line
Leave open
30
X4
O
X matrix drive line
Leave open
31
X5
O
X matrix drive line
Leave open
32
X6
O
X matrix drive line
Leave open
5
9530BS–AT42–10/09
Table 1-2.
I
O
P
6
Pin Listing (Continued)
Pin
Name
Type
33
X7
O
X matrix drive line
34
AVDD
P
Analog power
–
35
GND
P
Ground
–
36
Y0
I
Y line connection
Leave open
37
Y1
I
Y line connection
Leave open
38
Y2
I
Y line connection
Leave open
39
Y3
I
Y line connection
Leave open
40
Y4
I
Y line connection
Leave open
41
Y5
I
Y line connection
Leave open
42
Y6
I
Y line connection
Leave open
43
Y7
I
Y line connection
Leave open
44
Y8
I
Y line connection
Leave open
45
Y9
I
Y line connection
Leave open
46
Y10
I/O
Y line connection or X line in extended mode
Leave open
47
Y11
I/O
Y line connection or X line in extended mode
Leave open
48
Y12
I/O
Y line connection or X line in extended mode
Leave open
Input only
Output only, push-pull
Ground or power
Comments
I/O
OD
If Unused, Connect To...
Leave open
Input and output
Open drain output
mXT224
9530BS–AT42–10/09
mXT224
Schematic
49-ball UFBGA/VFBGA
Regulated Regulated
VDD
AVDD
1 mF
F4
VDD
Rp
Rp
G2
SDA
2
I C-COMPATIBLE
F3
SCL
G1
VDD
E3
G3
Rc
CHG
2
I C-COMPATIBLE
ADDRESS SELECT
F6
G6
B2
C6
D4
F2
F5
C7
AVDD
A1
AVDD
G5
X0
X1
X2
GPIO1
X3
GPIO2/SCK
X4
X5
GPIO3/MOSI
X6
X7
X8
mXT224
QT602240
X9
X10
X11
SDA
X12
SCL
X13
X14
N/C
X15
RESET
X16/Y13
X17/Y12
GPIO0/SYNC
X18/Y11
X19/Y10
CHG
ADDR_SEL
GND
GND
GND
GND
GND
Y9
Y8
Y7
Y6
Y5
Y4
Y3
Y2
Y1
Y0
G7
E5
F7
E6
E7
D6
D7
D5
B1
C2
C1
D3
MATRIX X DRIVE
G4
VDD
VDD
E4
1 mF
100 nF
F1
100 nF
NOTE: Bypass capacitors must be X7R or
X5R and placed <5 mm away from chip.
D1
D2
E1
E2
C3
A2
B3
A3
MATRIX
Y OR X*
1.3.1
B4
A4
C4
A5
B5
A6
C5
A7
B6
MATRIX Y SCAN IN
1.3
B7
* NOTE: Y10 to Y13 scan lines may be
used as additional X drive lines in
extended mode (a 100W resistor must
be added to each additional line).
7
9530BS–AT42–10/09
48-pin QFN
Regulated Regulated
VDD
AVDD
1 mF
Rp
Rp
16
SDA
2
I C-COMPATIBLE
17
SCL
15
VDD
14
18
Rc
CHG
2
I C-COMPATIBLE
ADDRESS SELECT
24
23
2
12
25
35
34
AVDD
3
AVDD
20
CHG
ADDR_SEL
GND
GND
GND
GND
Y9
Y8
Y7
Y6
Y5
Y4
Y3
Y2
Y1
Y0
26
27
28
29
30
MATRIX X DRIVE
22
VDD
X0
X1
X2
GPIO1
X3
GPIO2/SCK
X4
X5
GPIO3/MOSI
X6
X7
X8
mXT224
QT602240
X9
X10
X11
SDA
X12
SCL
X13
X14
N/C
X15
RESET
X16/Y13
X17/Y12
GPIO0/SYNC
X18/Y11
X19/Y10
31
32
33
4
5
6
7
8
9
10
11
1
MATRIX
Y OR X*
21
VDD
VDD
19
1 mF
100 nF
13
100 nF
NOTE: Bypass capacitors must be X7R or
X5R and placed <5 mm away from chip.
48
47
46
45
44
MATRIX Y SCAN IN
1.3.2
43
42
41
40
39
38
37
36
* NOTE: Y10 to Y13 scan lines may be
used as additional X drive lines in
extended mode (a 100W resistor must
be added to each additional line).
8
mXT224
9530BS–AT42–10/09
mXT224
2. Overview of the mXT224
2.1
Introduction
The mXT224 (AT42QT602240) uses a unique charge-transfer acquisition engine to implement
the QMatrix™ capacitive sensing method patented by Atmel®. This allows the measurement of
up to 224 mutual capacitance nodes in under 1 ms. Coupled with a state-of-the-art XMEGA™
CPU, the entire touchscreen sensing solution can measure, classify and track a single finger
touch every 4 ms if required.
The acquisition engine uses an optimal measurement approach to ensure almost complete
immunity from parasitic capacitance on the receiver inputs (Y lines). The engine includes
sufficient dynamic range to cope with touchscreen mutual capacitances spanning 0.5 pF to 5 pF,
allowing great flexibility for use with Atmel’s proprietary ITO pattern designs. One and two layer
ITO sensors are possible using glass or PET substrates.
The main AVR ® XMEGA CPU has, under its control, two powerful, yet low power,
microsequencer coprocessors. These combine to allow the signal acquisition, preprocessing,
postprocessing and housekeeping to be partitioned in an efficient and flexible way. This gives
ample scope for sensing algorithms, touch tracking or advanced shape-based filtering. An
in-circuit reflash can be performed over the chip’s hardware-driven two-wire interface
(I2C-compatible).
Overall, the mXT224 represents a step improvement over competing technologies, providing a
near optimal mix of low power, small size and low part count, while offering unrivalled true
multitouch performance.
9
9530BS–AT42–10/09
Revision History
10
Revision Number
History
Revision AS – September 2009
Initial release for chip revision 1.4
Revision BS – October 2009
QFN package details added
mXT224
9530BS–AT42–10/09
mXT224
Notes
11
9530BS–AT42–10/09
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© 2009 Atmel Corporation. All rights reserved. Atmel®, Atmel logo and combinations thereof, AVR ®, Adjacent Key Suppression ® and others are
registered trademarks, maXTouch™, AKS ™, QMatrix ™, XMEGA ™ and others are trademarks of Atmel Corporation or its subsidiaries. Other terms
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9530BS–AT42–10/09