AR1000 Series Resistive Touch Screen
Controller
DS41393A
Contact Information
Microchip Technology, Inc.
mTouch Touchscreen Controller Products
9055 N. 51
st
Street, Suite H
Brown Deer, WI 53223
www.Microchip.com
Phone: 414-355-4675
Fax: 414-355-4775
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EE
L
OQ
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EE
L
OQ
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© 2009, Microchip Technology Incorporated, Printed in the
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are for its PIC
®
MCUs and dsPIC
®
DSCs, K
EE
L
OQ
®
code hopping
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DS41393A-Page ii
© 2009 Microchip Technology, Inc.
TABLE OF CONTENTS
1
2
3
4
5
6
7
7.1
7.2
7.3
7.4
7.5
7.6
7.7
GENERAL.............................................................................................................................................. 1
FEATURES............................................................................................................................................ 1
APPLICATIONS..................................................................................................................................... 2
ORDERING............................................................................................................................................ 2
BLOCK DIAGRAM ................................................................................................................................. 2
PIN DIAGRAM ....................................................................................................................................... 3
FUNCTIONAL DESCRIPTION .............................................................................................................. 4
M
AIN
S
CHEMATIC
..............................................................................................................................................4
B
ILL OF
M
ATERIALS
...........................................................................................................................................4
4, 5, 8-W
IRE
S
ENSOR
S
ELECTION
......................................................................................................................5
4-
WIRE
T
OUCH
S
ENSOR
I
NTERFACE
....................................................................................................................5
5-
WIRE
T
OUCH
S
ENSOR
I
NTERFACE
....................................................................................................................6
8-
WIRE
T
OUCH
S
ENSOR
I
NTERFACE
....................................................................................................................7
C
OMMUNICATION
I
NTERFACE
..............................................................................................................................8
7.7.1
7.7.2
7.7.3
7.8
7.9
7.10
7.11
7.12
I
2
C............................................................................................................................................ 8
SPI........................................................................................................................................... 9
UART..................................................................................................................................... 10
S
TATUS
LED..................................................................................................................................................10
ESD C
ONSIDERATIONS
...................................................................................................................................11
N
OISE
C
ONSIDERATIONS
.................................................................................................................................11
T
OUCH
R
EPORTING
P
ROTOCOL
........................................................................................................................11
C
ONFIGURATION
R
EGISTERS
............................................................................................................................12
7.12.1
7.12.2
7.12.3
7.12.4
7.12.5
7.12.6
7.12.7
7.12.8
7.12.9
7.12.10
7.12.11
7.12.12
7.12.13
7.12.14
7.12.15
7.13
7.14
7.15
TouchThreshold Register (offset 0x02)................................................................................. 12
SensitivityFilter Register (offset 0x03)................................................................................... 12
SamplingFast Register (offset 0x04)..................................................................................... 13
SamplingSlow Register (offset 0x05) .................................................................................... 13
AccuracyFilterFast Register (offset 0x06) ............................................................................. 13
AccuracyFilterSlow Register (offset 0x07) ............................................................................ 13
SpeedThreshold Register (offset 0x08) ................................................................................ 13
SleepDelay Register (offset 0x0A) ........................................................................................ 14
PenUpDelay Register (offset 0x0B) ...................................................................................... 14
TouchMode Register (offset 0x0C).................................................................................... 15
TouchOptions Register (offset 0x0D) ................................................................................ 16
CalibrationInset Register (offset 0x0E).............................................................................. 16
PenStateReportDelay Register (offset 0x0F) .................................................................... 17
TouchReportDelay Register (offset 0x11) ......................................................................... 17
User Configuration – Spiking ............................................................................................. 17
C
OMMAND
F
ORMAT
.........................................................................................................................................17
C
OMMAND
R
ESPONSE
.....................................................................................................................................18
C
OMMANDS
....................................................................................................................................................18
7.15.1 Enable Touch - 0x12 ............................................................................................................. 18
7.15.2 Disable Touch - 0x13 ............................................................................................................ 18
7.15.3 Calibrate - 0x14 ..................................................................................................................... 19
7.15.3.1 How the Calibration Data is Encoded and Stored in EEPROM ..................................... 20
7.15.4 Register Read - 0x20 ............................................................................................................ 21
7.15.5 Register Write - 0x21............................................................................................................. 21
7.15.6 Register Start Address Request - 0x22................................................................................. 21
7.15.7 Registers Write to EEPROM - 0x23 ...................................................................................... 21
7.15.8 EEPROM Read - 0x28 .......................................................................................................... 22
7.15.9 EEPROM Write - 0x29 .......................................................................................................... 22
7.15.10
EEPROM Write to Registers - 0x2B .................................................................................. 22
7.16
C
ALIBRATION OF
T
OUCH
S
ENSOR WITH
C
ONTROLLER
.........................................................................................23
© 2009 Microchip Technology, Inc.
DS41393A-Page iii
8
8.1
8.2
8.3
8.4
8.5
8.6
BASICS OF RESISTIVE SENSORS ................................................................................................... 25
T
ERMINOLOGY
................................................................................................................................................25
G
ENERAL
.......................................................................................................................................................25
4-W
IRE
S
ENSOR
.............................................................................................................................................26
8-W
IRE
S
ENSOR
.............................................................................................................................................27
5-W
IRE
S
ENSOR
.............................................................................................................................................28
S
UMMARY
......................................................................................................................................................28
9
9.1
ELECTRICAL SPECIFICATIONS........................................................................................................ 29
A
BSOLUTE
M
AXIMUM
R
ATINGS
(†).....................................................................................................................29
10
10.1
10.2
10.3
PACKAGING .................................................................................................................................... 30
20 L
EAD
SOIC ...............................................................................................................................................30
20 L
EAD
SSOP ..............................................................................................................................................31
20 L
EAD
QFN (ML) ........................................................................................................................................32
FIGURES
Figure 1: Block Diagram................................................................................................................................ 2
Figure 2 : Pin Diagrams – SOIC / SSOP and QFN Packages..................................................................... 3
Figure 3 : Main Schematic (SOIC, SSOP package pin out) ........................................................................ 4
Figure 4 : 4-wire Touch Sensor Interface..................................................................................................... 5
Figure 5 : 5-wire Touch Sensor Interface..................................................................................................... 6
Figure 6 : 8-wire Touch Sensor Interface..................................................................................................... 7
Figure 7 : I
2
C Timing Diagram – Receive Data............................................................................................ 8
Figure 8 : I
2
C Timing Diagram – Transmit Data........................................................................................... 8
Figure 9 : I
2
C Timing Diagram – Touch Report Protocol ............................................................................. 9
Figure 10 : I
2
C Timing Diagram – Command Protocol................................................................................. 9
Figure 11 : SPI Timing Diagram – Bit Timing............................................................................................... 9
Figure 12 : SPI Timing Diagram – Touch Report Protocol ........................................................................10
Figure 13 : SPI Timing Diagram – Command Protocol.............................................................................. 10
Figure 14: 4-Wire Decoding ........................................................................................................................ 26
Figure 15: 8-Wire Decoding ........................................................................................................................ 27
Figure 16: 5-Wire Decoding ........................................................................................................................ 28
Figure 17 : 20 Lead SOIC Package ........................................................................................................... 30
Figure 18 : 20 Lead SSOP Package.......................................................................................................... 31
Figure 19 : 20 Lead QFN Package ............................................................................................................ 32
TABLES
Table 1: Ordering Part Numbers................................................................................................................... 2
Table 2: Pin Descriptions .............................................................................................................................. 3
Table 3 : Bill of Materials.............................................................................................................................. 4
Table 4 : 4/8-wire vs 5-wire Selection .......................................................................................................... 5
Table 5 : Communication Selection ............................................................................................................. 8
Table 6 : Communication Pins ..................................................................................................................... 8
Table 7 : Touch Coordinate Reporting Protocol......................................................................................... 11
Table 8 : Configuration Registers .............................................................................................................. 12
Table 9 : Command Set Summary............................................................................................................. 18
Table 10 : Sensor Comparison .................................................................................................................. 25
DS41393A-Page iv
© 2009 Microchip Technology, Inc.
1 GENERAL
The mTouch AR1000 Series Resistive Touch Screen Controller is a complete, easy to integrate, cost effective,
and universal touch screen controller chip solution.
The AR1000 Series is designed for high volume, small form factor touch solutions with quick time to market
requirements.
Developed by touch experts with over 15 years experience, the AR1000 Series has sophisticated proprietary
touch screen decoding algorithms allowing it to send your application fully processed and reliable touch
coordinates.
2 FEATURES
Special Features:
• RoHS Compliant
• Power-Saving Sleep mode
• Industrial Temperature Range
• Built in drift compensation algorithm
• 128 Bytes of user EEPROM
• 4 x 4 mm QFN package
Power Requirements:
• Operating Voltage: 3.3 to 5.0 volts ±5%
• Standby Sleep Current: <1uA
• Operating “No touch” Current: 3.0mA typ.
• Operating “Touch” Current: 17mA typ
with a touch sensor having 200Ω layers.
- Actual current is dependent on the touch sensor used.
Touch Modes:
• Off, Stream, Down, Up, and more.
Touch Sensor Support:
• 4 wire, 5 wire, and 8 wire analog resistive
• Lead to Lead Resistance: 50Ω to 2,000Ω
• Layer to Layer Capacitance: 0 to 0.5uF
• Touch Sensor Time Constant: 500us maximum
Touch Resolution:
• 10-bit resolution maximum
Touch Coordinate Report Rate:
• 140 reports per second typ.
with a touch sensor of 0.02uF with 200Ω layers.
- Actual report rate is dependent on the touch sensor used.
Communications:
• SPI, slave mode, p/n AR1020
2
• I C™, slave mode, p/n AR1020
• UART, 9600 bps, p/n AR1010
Sensor Support
All 4, 5, and 8-wire sensors are supported, regardless of manufacturer or construction.
See
BASICS OF RESISTIVE SENSORS
section.
Low-Power Wake-Up
Wake-up from power saving sleep mode, via a touch or communication input.
Configuration Registers
Configuration registers provide user configuration of controller features.
See
Configuration Registers
section.
Touch Algorithms
Algorithms provide for good calibration-corrected coordinates, with no additional development or code.
Touch decoding
Coordinate data filtering
Calibration corrected coordinate option
Built-in touch modes
Communication Control
AR1010 supports UART communication. AR1020 supports I2C and SPI communication.
See
Communication Interface
section.
© 2009 Microchip Technology, Inc.
DS41393A-Page 1
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