Datasheet AR 1021, AR 1011 Datasheet

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Page 1

AR1000 Series Resistive

Touch Screen Controller

Data Sheet

 2009-2012 Microchip Technology Inc. Preliminary DS41393B

Page 2

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YSTEM

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== ISO/TS 16949 ==

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

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Trademarks

The Microchip name and logo, the Microchip logo, dsPIC, K

EELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,

PIC

logo, rfPIC and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.

FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor, MXDEV, MXLAB, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A.

Analog-for-the-Digital Age, Application Maestro, chipKIT, chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit, PICtail, REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, UniWinDriver, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.

SQTP is a service mark of Microchip Technology Incorporated in the U.S.A.

All other trademarks mentioned herein are property of their respective companies.

Printed on recycled paper.

QUALITY MANAGEMENT S

DS41393B-page 2 Preliminary  2009-2012 Microchip Technology Inc.

ISBN: 9781620761366

Microchip received ISO/TS-16949:2009 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified.

MCUs and dsPIC® DSCs, KEELOQ

code hopping

Page 3

AR1000 SERIES RESISTIVE TOUCH

SCREEN CONTROLLER

AR1000 Series Resistive Touch Screen Controller

Special Features:

• RoHS Compliant

• Power-Saving Sleep mode

• Industrial Temperature Range

• Built-in Drift Compensation Algorithm

• 128 Bytes of User EEPROM

Power Requirements:

• Operating Voltage: 2.5-5.0V ±5%

• Standby Current:

- 5V: 85 uA, typical; 125 uA (maximum)

- 2.5V: 40 uA, typical; 60 uA (maximum)

• Operating “No touch” Current:

- 3.0 mA (typical)

• Operating “Touch” Current:

- 17 mA, typical, with a touch sensor having 200 layers.

- Actual current is dependent on the touch sensor used

• AR1011/AR1021 Brown-Out Detection (BOR) set to 2.2V.

Touch Modes:

• Off, Stream, Down, Up and more.

Touch Sensor Support:

• 4-Wire, 5-Wire and 8-Wire Analog Resistive

• Lead-to-Lead Resistance: 50-2,000typical)

• Layer-to-Layer Capacitance: 0-0.5 uF

• Touch Sensor Time Constant: 500 us (maximum)

Touch Resolution:

• 10-bit Resolution (maximum)

Touch Coordinate Report Rate:

• 140 Reports Per Second (typical) with a Touch Sensor of 0.02 uF with 200 Layers

• Actual Report Rate is dependent on the Touch Sensor used.

Communications:

• SPI, Slave mode, p/n AR1021

2CTM

•I

• UART, 9600 Baud Rate, p/n AR1011

, Slave mode, p/n, AR1021

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 3

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

1.0 Device Overview .......................................................................................................................................................................... 5

2.0 Basics of Resistive Sensors......................................................................................................................................................... 7

3.0 Hardware.................................................................................................................................................................................... 11

C Communications .................................................................................................................................................................. 17

4.0 I

5.0 SPI Communications.................................................................................................................................................................. 21

6.0 UART Communications.............................................................................................................................................................. 25

7.0 Touch Reporting Protocol........................................................................................................................................................... 27

8.0 Configuration Registers.............................................................................................................................................................. 29

9.0 Commands ................................................................................................................................................................................. 35

10.0 Application Notes ....................................................................................................................................................................... 45

11.0 Electrical Specifications.............................................................................................................................................................. 51

12.0 Packaging Information................................................................................................................................................................ 53

Appendix A: Revision History............................................................................................................................................................... 63

Appendix B: Device Differences........................................................................................................................................................... 64

Index .................................................................................................................................................................................................... 65

The Microchip Web Site....................................................................................................................................................................... 67

Customer Change Notification Service ................................................................................................................................................ 67

Customer Support ................................................................................................................................................................................ 67

Reader Response ................................................................................................................................................................................ 68

TO OUR VALUED CUSTOMERS

It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and enhanced as new volumes and updates are introduced.

If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via E-mail at docerrors@microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We welcome your feedback.

Most Current Data Sheet

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You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page. The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).

Errata

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To determine if an errata sheet exists for a particular device, please check with one of the following:

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using.

Customer Notification System

DS41393B-page 4 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

20 19 18

17 16

15 14 13 12 11

XX+

5WSX-

YY+

SX+

SDI/SDA/RX

SCK/SCL/TX

1 2

5 6 7 8 9

M1 SYM2 WAKE

SIQ SY+ SS SDO

AR1000 Series (SSOP, SOIC)

15 14 13 12 11

X+

5WSX-

YY+

SX+

1 2 3

789

SY-

M2 WAKE SIQ

SY+ SS

VDD

VSS

X-

SDO

SCK/SCL/TX

SDI/SDA/RX

AR1000 Series (QFN)

1.0 DEVICE OVERVIEW

The Microchip mTouchTM AR1000 Series Resistive Touch Screen Controller is a complete, easy to integrate, cost-effective and universal touch screen controller chip.

The AR1000 Series has sophisticated proprietary touch screen decoding algorithms to process all touch data, saving the host from the processing overhead. Providing filtering capabilities beyond that of other low-cost devices, the AR1000 delivers reliable, validated, and calibrated touch coordinates.

Using the on-board EEPROM, the AR1000 can store and independently apply the calibration to the touch coordinates before sending them to the host. This unique combination of features makes the AR1000 the most resource-efficient touch screen controller for system designs, including embedded system integrations.

FIGURE 1-1: BLOCK DIAGRAM

1.1 Applications

The AR1000 Series is designed for high volume, small form factor touch solutions with quick time to market requirements – including, but not limited to:

• Mobile communication devices

• Personal Digital Assistants (PDA)

• Global Positioning Systems (GPS)

• Touch Screen Monitors

•KIOSK

• Media Players

• Portable Instruments

• Point of Sale Terminals

FIGURE 1-2: PIN DIAGRAM

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

TABLE 1-1: PIN DESCRIPTIONS

SSOP, SOIC QFN

118 V

2 19 M1 Communication Selection

3 20 SY- Sense Y- (8-wire). Tie to V

4 1 M2 4/8-wire or 5-wire Sensor

5 2 WAKE Touch Wake-up/Touch Detection

6 3 SIQ LED Drive/SPI Interrupt. No

7 4 SY+ Sense Y+ (8-wire). Tie to V

8 5 SS Slave Select (SPI). Tie to V

9 6 SDO SPI Serial Data Output/I

10 7 NC No connection. No connect or tie

11 8 SCK/SCL/TX SPI/I

12 9 NC No connection. No connect or tie

13 10 SDI/SDA/RX I2C™ Serial Data/SPI Serial Data

14 11 SX+ Sense X+ (8-wire). Tie to V

15 12 Y+ Y+ Drive

16 1 3 Y- Y- Drive

17 14 5WSX- 5W Sense (5-wire)/Sense X-

18 15 X+ X+ Drive

19 16 X- X- Drive

20 17 V

Function Description/Comments

DD Supply Voltage

not used.

Selection

connect, if not used.

not used.

Interrupt. Tie to Vss, if UART.

to VSS or VDD.

C™ Serial Clock/UART

Transmit

to VSS or VDD.

Input/UART Receive

not used.

(8-wire). Tie to V

SS Supply Voltage Ground

SS, if

C™

SS, if

SS, if not used.

DS41393B-page 6 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

2.0 BASICS OF RESISTIVE SENSORS

2.1 Terminology

ITO (Indium Tin Oxide) is the resistive coating that makes up the active area of the touch sensor. ITO is a transparent semiconductor that is sputtered onto the touch sensor layers.

Flex or Film or Topsheet user touches. Flex refers to the fact that the top layer physically flexes from the pressure of a touch.

Stable or Glass interfaces against the display.

Spacer Adhesive the flex and stable layers together around the perimeter of the sensor.

Spacer Dots separation between the flex and stable layers. The dots are typically printed onto the stable layer.

is a frame of adhesive that connects

maintain physical and electrical

is the top sensor layer that a

is the bottom sensor layer that

Bus Bars or Silver Frit electrically connect the ITO on the flex and stable layers to the sensor’s interface tail. Bus bars are typically screen printed silver ink. They are typically much lower in resistivity than the ITO.

is the left and right direction on the touch sensor.

X-Axis

is the top and bottom direction on the touch

Y-Ax is sensor.

Drive Lines sensor.

supply a voltage gradient across the

2.2 General

Resistive 4, 5, and 8-wire touch sensors consist of two facing conductive layers, held in physical separation from each other. The force of a touch causes the top layer to deflect and make electrical contact with the bottom layer.

Touch position measurements are made by applying a voltage gradient across a layer or axis of the touch sensor. The touch position voltage for the axis can be measured using the opposing layer.

A comparison of typical sensor constructions is shown below in Tabl e 2 -1 .

TABLE 2-1: SENSOR COMPARISON

Sensor Comments

4-Wire Less expensive than 5-wire or 8-wire

Lower power than 5-wire More linear (without correction) than 5-wire Touch inaccuracies occur from flex layer damage or resistance changes

5-Wire Maintains touch accuracy with flex layer damage

Inherent nonlinearity often requires touch data correction Touch inaccuracies occur from resistance changes

8-Wire More expensive than 4-wire

Lower power than 5-wire More linear (without correction) than 5-wire Touch inaccuracies occur from flex layer damaged Maintains touch accuracy with resistance changes

The AR1000 Series Resistive Touch Screen Controllers will work with any manufacturers of analog resistive 4, 5 and 8-wire touch screens. The communications and decoding are included, allowing the user the quickest simplest method of interfacing analog resistive touch screens into their applications.

The AR1000 Series was designed with an understanding of the materials and processes that make up resistive touch screens. The AR1000 Series Touch Controller is not only reliable, but can enhance the reliability and longevity of the resistive touch screen, due to its advanced filtering algorithms and wide range of operation.

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 7

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

2.3 4-Wire Sensor

A 4-wire resistive touch sensor consists of a stable and flex layer, electrically separated by spacer dots. The layers are assembled perpendicular to each other. The touch position is determined by first applying a voltage gradient across the flex layer and using the stable layer to measure the flex layer’s touch position voltage. The second step is applying a voltage gradient across the stable layer and using the flex layer to measure the stable layer’s touch position voltage.

The measured voltage at any position across a driven axis is predictable. A touch moving in the direction of the driven axis will yield a linearly changing voltage. A touch moving perpendicular to the driven axis will yield a relatively unchanging voltage (See Figure 2-1).

FIGURE 2-1: 4-WIRE DECODING

DS41393B-page 8 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

2.4 8-Wire Sensor

An 8-wire resistive touch sensor consists of a stable and flex layer, electrically separated by spacer dots. The layers are assembled perpendicular to each other. The touch position is determined by first applying a voltage gradient across the flex layer and using the stable layer to measure the flex layer’s touch position voltage. The second step is applying a voltage gradient across the stable layer and using the flex layer to measure the stable layer’s touch position voltage.

FIGURE 2-2: 8-WIRE DECODING

The basic decoding of an 8-wire sensor is similar to a 4-wire. The difference is that an 8-wire sensor has four additional interconnects used to reference sensor voltage back to the controller.

A touch system may experience voltage losses due to resistance changes in the bus bars and connection between the controller and sensor. The losses can vary with product use, temperature, and humidity. In a 4-wire sensor, variations in the losses manifest themselves as error or drift in the reported touch location. The four additional sense lines found on 8-wire sensors are added to dynamically reference the voltage to correct for this fluctuation during use (See Figure 2-2).

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 9

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

2.5 5-Wire Sensor

A 5-wire resistive touch sensor consists of a flex and stable layer, electrically separated by spacer dots. The touch position is determined by first applying a voltage gradient across the stable layer in the X-axis direction and using the flex layer to measure the axis touch position voltage. The second step is applying a voltage gradient across the stable layer in the Y-axis direction and using the flex layer to measure the axis touch position voltage.

The voltage is not directly applied to the edges of the active layer, as it is for 4-wire and 8-wire sensors. The voltage is applied to the corners of a 5-wire sensor.

FIGURE 2-3: 5-Wire Decoding

To measure the X-axis, the left edge of the layer is driven with 0V (ground), using connections to the upper left and lower left sensor corners. The right edge is driven with +5 V right and lower right sensor corners.

To measure the Y-axis, the top edge of the layer is driven with 0V (ground), using connections to the upper left and upper right sensor corners. The bottom edge is driven with +5 V and lower right sensor corners.

DC, using connections to the upper

DC, using connections to the lower left

DS41393B-page 10 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

3.0 HARDWARE

3.1 Main Schematic

A main application schematic for the SOIC/SSOP package pinout is shown in Figure 3-1.

See Figure 1-2 for the QFN package pinout.

FIGURE 3-1: MAIN SCHEMATIC (SOIC/SSOP PACKAGE PINOUT)

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 11

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

3.2 4, 5, 8-Wire Sensor Selection

The desired sensor type of 4/8-wire or 5-wire is hardware selectable using pin M2.

TABLE 3-1: 4/8-WIRE vs. 5-WIRE

SELECTION

Type M2 pin

4/8-wire V

5-wire VDD

If 4/8-wire has been hardware-selected, then the choice of 4-wire or 8-wire is software-selectable via the TouchOptions Configuration register.

When 4/8-wire is hardware-selected, the controller defaults to 4-wire operation. If 8-wire operation is desired, then the TouchOptions Configuration register must be changed.

3.3 4-Wire Touch Sensor Interface

Sensor tail pinouts can vary by manufacturer and part number. Ensure that both sensor tail pins for one sensor axis (layer) are connected to the controller’s X-/X+ pins and the tail pins for the other sensor axis (layer) are connected to the controller’s Y-/Y+ pins. The controller’s X-/X+ and Y-/Y+ pin pairs do not need to connect to a specific sensor axis. The orientation of controller pins X- and X+ to the two sides of a given sensor axis is not important. Likewise, the orientation of controller pins Y- and Y+ to the two sides of the other sensor axis is not important.

Connections to a 4-wire touch sensor are as follows (See Figure 3-2).

FIGURE 3-2: 4-WIRE TOUCH SENSOR INTERFACE

Tie unused controller pins 5WSX-, SX+, SY-, and SY+ to V

SS.

See Section 3.8 “ESD Considerations” and

Section 3.9 “Noise Considerations” for important

information regarding the capacitance of the controller schematic hardware.

DS41393B-page 12 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

3.4 5-Wire Touch Sensor Interface

Sensor tail pinouts can vary by manufacturer and part number. Ensure sensor tail pins for one pair of diagonally related sensor corners are connected to the controller’s X-/X+ pins and the tail pins for the other pair of diagonally related corners are connected to the controller’s Y-/Y+ pins.

The controller’s X-/X+ and Y-/Y+ pin pairs do not need to connect to a specific sensor axis. The orientation of controller pins X- and X+ to the two selected diagonal sensor corners is not important.

Likewise, the orientation of controller pins Y- and Y+ to the other two selected diagonal sensor corners is not important. The sensor tail pin connected to its top layer must be connected to the controller’s 5WSX- pin.

Connections to a 5-wire touch sensor are shown in

Figure 3-3 below.

FIGURE 3-3: 5-WIRE TOUCH SENSOR INTERFACE

Tie unused controller pins SX+, SY-, and SY+ to VSS.

See “Section 3.8 “ESD Considerations” and

Section 3.9 “Noise Considerations” for important

information regarding the capacitance of the controller schematic hardware.

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 13

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

3.5 8-Wire Touch Sensor Interface

Sensor tail pinouts can vary by manufacturer and part number. Ensure both sensor tail pins for one sensor axis (layer) are connected to the controller’s X-/X+ pins and the tail pins for the other sensor axis (layer) are connected to the controller’s Y-/Y+ pins.

The controller’s X-/X+ and Y-/Y+ pin pairs do not need to connect to a specific sensor axis. The orientation of controller pins X- and X+ to the two sides of a given sensor axis is not important. Likewise, the orientation of controller pins Y- and Y+ to the two sides of the other sensor axis is not important.

The 8-wire sensor differs from a 4-wire sensor in that each edge of an 8-wire sensor has a secondary connection brought to the sensor’s tail. These secondary connections are referred to as “sense” lines. The controller pins associated with the sense line for an 8-wire sensor contain an ‘S’ prefix in their respective names. For example, the SY- pin is the sense line connection associated with the main Y- pin connection.

Consult with the sensor manufacturer ’s specification to determine which member of each edge connected pair is the special 8-wire “sense” connection. Incorrectly connecting the sense and excite lines to the controller will adversely affect performance.

The controller requires that the main and “sense” tail pin pairs for sensor edges be connected to controller pin pairs as follows:

• Y- and SY-

• Y+ and SY+

• X- and 5WSX-

• X+ and SX+

Connections to a 8-wire touch sensor are shown in

Figure 3-4 below.

FIGURE 3-4: 8-WIRE TOUCH SENSOR INTERFACE

See Section 3.8 “ESD Considerations” and

Section 3.9 “Noise Considerations” for important

information regarding the capacitance of the controller schematic hardware.

DS41393B-page 14 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

3.6 Status LED

The LED and associated resistor are optional.

FIGURE 3-5:

The LED serves as a status indicator that the controller is functioning. It will slow flash when the controller is running with no touch in progress. It will flicker quickly (mid-level on) when a touch is in progress.

If the LED is used with SPI communication, then the LED will be off with no touch and flicker quickly (mid-level on) when a touch is in progress.

Note: If the SIQ pin is not used, it must be left as

a No Connect and NOT tied to circuit V

SS.

DD or

3.7 WAKE Pin

The AR1000’s WAKE pin is described as “Touch Wake-Up/Touch Detection”. It serves the following three roles in the controller’s functionality:

• Wake-up from touch

• Touch detection

• Measure sensor capacitance

The application circuit shows a 20 KΩ resistor connected between the WAKE pin and the X- pin on the controller chip. The resistor is required for product operation, based on all three of the above roles.

3.8 ESD Considerations

ESD protection is shown on the 4-wire, 5-wire, and 8-wire interface applications schematics.

The capacitance of alternate ESD diodes may adversely affect touch performance. A lower capacitance is better. The PESD5V0S1BA parts shown in the reference design have a typical capacitance of 35 pF. Test to ensure that selected ESD protection does not degrade touch performance.

ESD protection is shown in the reference design, but acceptable protection is dependent on your specific application. Ensure your ESD solution meets your design requirements.

3.9 Noise Considerations

Touch sensor filtering capacitors are included in the reference design.

Warning: Changing the value of the capacitors may adversely affect performance of the touch system.

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 15

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

NOTES:

DS41393B-page 16 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

4.0 I2CTM COMMUNICATIONS

The AR1021 is an I2C slave device with a 7-bit address of 0x4D, supporting up to 400 kHz bit rate.

A master (host) device interfaces with the AR1021.

4.1 I2C Hardware Interface

A summary of the hardware interface pins is shown below in Tab le 4 - 1.

TABLE 4-1: I2C HARDWARE INTERFACE

AR1021 Pin Description

M1 Connect to V

SS to select I

SCL Serial Clock to master I2C

SDA Serial Data to master I

SDO Data ready interrupt output to master

M1 Pin

• The M1 pin must be connected to V

ure the AR1021 for I

C communications.

SS to config-

SCL Pin

• The SCL (Serial Clock) pin is electrically

open-drain and requires a pull-up resistor, typically 2.2 K to 10 K, from SCL to V

DD.

• SCL Idle state is high.

SDA Pin

• The SDA (Serial Data) pin is electrically

open-drain and requires a pull-up resistor, typically 2.2K to 10K, from SDA to V

DD.

• SDA Idle state is high.

• Master write data is latched in on SCL rising

edges.

• Master read data is latched out on SCL falling

edges to ensure it is valid during the subsequent SCL high time.

SDO Pin

• The SDO pin is a driven output interrupt to the

master.

• SDO Idle state is low.

• SDO will be asserted high when the AR1021 has

data ready (touch report or command response) for the master to read.

C™ communications

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 17

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

4.2 I2C Pin Voltage Level Characteristics

TABLE 4-2: I2C PIN VOLTAGE LEVEL CHARACTERISTICS

Function Pin Input Output

SCL/SCK SCL/SCK/TX V

SDO SDO — V

SDA SDI/SDA/RX VSS ≤ VIL ≤ 0.2*VDD

Note 1: These parameters are characterized but not tested.

2: At 10 mA. 3: At –4 mA.

SS ≤ VIL≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

4.3 Addressing

The AR1021’s device ID 7-bit address is: 0x4D (0b1001101)

TABLE 4-3: I2C DEVICE ID ADDRESS

Device ID Address, 7-bit

A7 A6 A5 A4 A3 A2 A1

1001101

TABLE 4-4: I2C DEVICE WRITE ID

ADDRESS

A7 A6 A5 A4 A3 A2 A1 A0

1 0 011010 0x9A

TABLE 4-5: I2C DEVICE READ ID

A7 A6 A5 A4 A3 A2 A1 A0

1 0 011011 0x9B

4.4 Master Read Bit Timing

Master read is to receive touch reports and command responses from the AR1021.

• Address bits are latched into the AR1021 on the rising edges of SCL.

• Data bits are latched out of the AR1021 on the rising edges of SCL.

• ACK is presented (by AR1021 for address, by master for data) on the ninth clock.

• The master must monitor the SCL pin prior to asserting another clock pulse, as the AR1021 may be holding off the master by stretching the clock.

—

SS ≤ VOL

(1.25*VDD – 2.25V)

Open-drain

(1)

≤ (1.2V – 0.15*VDD)

ADDRESS

(3)

≤ VOH

(1)

≤ VDD

(2)

FIGURE 4-1: I2C MASTER READ BIT TIMING DIAGRAM

Steps

1. SCL and SDA lines are Idle high.

2. Master presents “Start” bit to the AR1021 by taking SDA high-to-low, followed by taking SCL high-to-low.

3. Master presents 7-bit Address, followed by a R/W = 1 (Read mode) bit to the AR1021 on SDA, at the rising edge of eight master clock (SCL) cycles.

DS41393B-page 18 Preliminary  2009-2012 Microchip Technology Inc.

4. AR1021 compares the received address to its device ID. If they match, the AR1021 acknowledges (ACK) the master sent address by presenting a low on SDA, followed by a low-high-low on SCL.

5. Master monitors SCL, as the AR1021 may be “clock stretching”, holding SCL low to indicate that the master should wait.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

6. Master receives eight data bits (MSb first) presented on SDA by the AR1021, at eight sequential master clock (SCL) cycles. The data is latched out on SCL falling edges to ensure it is valid during the subsequent SCL high time.

7. If data transfer is not complete, then:

- Master acknowledges (ACK) reception of the eight data bits by presenting a low on SDA, followed by a low-high-low on SCL.

- Go to step 5.

8. If data transfer is complete, then:

- Master acknowledges (ACK) reception of the eight data bits and a completed data transfer by presenting a high on SDA, followed by a low-high-low on SCL.

9. Master presents a “Stop” bit to the AR1021 by taking SCL low-high, followed by taking SDA low-to-high.

4.5 Master Write Bit Timing

Master write is to send supported commands to the AR1021.

• Address bits are latched into the AR1021 on the

rising edges of SCL.

• Data bits are latched into the AR1021 on the

rising edges of SCL.

• ACK is presented by AR1021 on the ninth clock.

• The master must monitor the SCL pin prior to

asserting another clock pulse, as the AR1021 may be holding off the master by stretching the clock.

FIGURE 4-2: I2C MASTER WRITE BIT TIMING DIAGRAM

Steps

1. SCL and SDA lines are Idle high.

2. Master presents “Start” bit to the AR1021 by taking SDA high-to-low, followed by taking SCL high-to-low.

3. Master presents 7-bit Address, followed by a R/W = 0 (Write mode) bit to the AR1021 on SDA, at the rising edge of eight master clock (SCL) cycles.

4. AR1021 compares the received address to its device ID. If they match, the AR1021 acknowledges (ACK) the master sent address by presenting a low on SDA, followed by a low-high-low on SCL.

5. Master monitors SCL, as the AR1021 may be “clock stretching”, holding SCL low to indicate the master should wait.

6. Master presents eight data bits (MSb first) to the AR1021 on SDA, at the rising edge of eight master clock (SCL) cycles.

7. AR1021 acknowledges (ACK) receipt of the eight data bits by presenting a low on SDA, followed by a low-high-low on SCL.

8. If data transfer is not complete, then go to step 5.

9. Master presents a “Stop” bit to the AR1021 by taking SCL low-high, followed by taking SDA low-to-high.

4.6 Clock Stretching

The master normally controls the clock line SCL. Clock stretching is when the slave device holds the SCL line low, indicating to the master that it is not ready to continue the communications.

During communications, the AR1021 may hold off the master by stretching the clock with a low on SCL.

The master must monitor the slave SCL pin to ensure the AR1021 is not holding it low, prior to asserting another clock pulse for transmitting or receiving.

4.7 AR1020 Write Conditions

The AR1020 part does not implement clock stretching on write conditions.

A 50 us delay is needed before the Stop bit, when clocking a command to the AR1020.

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4.8 Touch Report Protocol

Touch coordinates, when available, are provided to the master by the AR1021 in the following protocol (See

Figure 4-3).

FIGURE 4-3: I2C TOUCH REPORT PROTOCOL

Note that the IRQ signal shown above occurs on the SDO pin of the AR1021.

4.9 Command Protocol

The master issues supported commands to the AR1021 in the following protocol.

Below is an example of the ENABLE_TOUCH command (see Figure 4-4).

FIGURE 4-4: I2C COMMAND PROTOCOL

Note that the IRQ shown above occurs on the SDO pin.

• 0x9A AR1021 Device ID address

• 0x00 Protocol command byte (send 0x00 for the protocol command register)

• 0x55 Header

• 0x01 Data size

• 0x12 Command

4.10 Sleep State

Pending communications are not maintained through a sleep/wake cycle.

If the SDO pin is asserted for a pending touch report or command response, and the AR1021 enters a Sleep state, prior to the master performing a read on the data, then the data is lost.

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5.0 SPI COMMUNICATIONS

SPI operates in Slave mode with an Idle low SCK and data transmitted on the SCK falling edge.

5.1 SPI Hardware Interface

A summary of the hardware interface pins is shown below in Tab le 5 - 1.

TABLE 5-1: SPI HARDWARE INTERFACE

AR1021 Pin Description

M1 Connect to V

SDI Serial data sent from master

SCK Serial clock to master

SDO Serial data to master SPI

SIQ

SCK Pin

• The AR1021 controller’s SCL/SCK/TX pin receives Serial Clock (SCK), controlled by the host.

• The Idle state of the SCK should be low.

• Data is transmitted on the falling edge of SCK.

SDI Pin

• The AR1021 controller’s SDI/SDA/RX pin reads Serial Data Input (SDI), sent by the host.

SDO Pin

• The AR1021 controller’s SDO pin presents Serial Data Output (SDO) to the host.

Interrupt output to master (optional)

Slave Select (optional)

DD to select SPI communications

SIQ Pin

• The AR1021 controller’s SIQ pin provides an optional interrupt output from the controller to the host.

• The SIQ pin is asserted high when the controller has data available (a touch report or a command response) for the host.

• The SIQ pin is deasserted after the host clocks out the first byte of the data packet.

Note: The AR1000 Development kit PICkit™

Serial Pin 1 is designated for the SIQ interrupt pin after the firmware updated is executed for the PICkit.

SS Pin

• The AR1021 controller’s SS pin provides optional “slave select” functionality.

SS Pin Level AR1021 Select

VSS

VDD

In the ‘inactive’ state, the controller’s SDO pin presents a high-impedance in order to prevent bus contention with another device on the SPI bus.

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Active

Inactive

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5.2 SPI Pin Voltage Level Characteristics

TABLE 5-2: SPI PIN VOLTAGE CHARACTERISTICS

Operating Voltage: 2.5V ≤ VDD ≤ 5.25V

Function Pin Input Output

SCK SCL/SCK/TX V

SDI SDI/SDA/RX V

SS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

SS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

—

SDO SDO — VSS ≤ VOL

(1.25*VDD – 2.25V)

SIQ SIQ — VSS ≤ VOL

(1.25*VDD – 2.25V)

SS SS VSS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

Note 1: These parameters are characterized but not tested.

2: At 10 mA. 3: At -4 mA.

5.3 Data Flow

SPI data is transferred by the host clocking the AR1021 controller’s Serial Clock (SCK) pin.

Each host driven clock cycle simultaneously shifts a bit of data into and out from the AR1021 controller:

• Out from the AR1021 controller’s Serial Data Out

(SDO) line.

• Into the AR1021 controller’s Serial Data In (SDI)

line.

The data is shifted Most Significant bit (MSb) first.

If the host clocks data out from the AR1021 controller when no valid data is available, then a byte value of 0x4d will be presented by the controller.

5.4 Touch Report Protocol

The AR1021 controller’s touch reporting is interrupt driven:

• The AR1021 controller asserts the SIQ interrupt pin high when it has a touch report ready.

• The host clocks out the bytes of the touch report packet from the AR1021 controller.

• The AR1021 controller clears the SIQ interrupt pin low, after the first byte of the touch report packet has been clocked out by the host.

The communication protocol for the AR1021 controller reporting touches to the host as shown below in

Figure 5-1.

(1)

≤ (1.2V – 0.15*VDD)

(3)

≤ VOH

(1)

≤ (1.2V – 0.15*VDD)

(3)

≤ VOH

(1)

≤ VDD

(1)

≤ VDD

(2)

FIGURE 5-1: SPI TOUCH REPORT PROTOCOL

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5.5 Command Protocol

The AR1021 controller receives commands from the host as follows:

• The host clocks the bytes of a command to the AR1021 controller.

• The AR1021 controller asserts the SIQ interrupt pin high when it is ready with a response to the command sent by the host.

• The host clocks out the bytes of the command response from the AR1021 controller.

• The AR1021 controller clears the SIQ interrupt pin low, after the first byte of the command response has been clocked out by the host.

The communication protocol for the host sending the ENABLE_TOUCH command to the AR1021 controller is shown below in Figure 5-2.

FIGURE 5-2: SPI TIMING DIAGRAM – COMMAND PROTOCOL (ENABLE_TOUCH)

5.6 SPI Bit Timing – General

General timing waveforms are shown below in

Figure 5-3.

FIGURE 5-3: SPI GENERAL BIT TIMING WAVEFORM

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5.7 Timing – Bit Details

5.7.1 BIT RATE

The SPI standard does not specify a maximum data rate for the serial bus. In general, SPI data rates can be in MHz. Peripherals devices, such as the AR1021 controller, specify their own unique maximum SPI data rates.

The maximum SPI bit rate for the AR1021 controller is ~900 kHz.

Characterization has been performed at bit rates of ~39 kHz and ~156 kHz.

FIGURE 5-4: SPI BIT TIMING – DETAIL

5.7.2 INTER-BYTE DELAY

The AR1021 controller requires an inter-byte delay of ~50 us. This means the host should wait ~50 us between the end of clocking a given byte and the start of clocking the next byte.

5.7.3 BIT TIMING – DETAIL

Characterized timing details are shown below, in

Figure 5-4.

TABLE 5-3: SPI BIT TIMING MIN. AND MAX. VALUES

Parameter Number

10 SS↓ (select) to SCK↑ (initial) 500 — ns

11 SCK high 550 — ns

12 SCK low 550 — ns

13 SCK↓ (last) to SS↑ (deselect) 800 — ns

14 SDI setup before SCK↓ 100 — ns

15 SDI hold after SCK↓ 100 — ns

16 SDO valid after SCK↓ —150ns

17 SDO↑ rise — 50 ns

18 SDO↓ fall — 50 ns

19 SS↑ (deselect) to SDO High-z 10 50 ns

Note 1: Parameters are characterized, but not tested.

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(1)

Parameter Description Min. Max. Units

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6.0 UART COMMUNICATIONS

TABLE 6-1: UART HARDWARE INTERFACE

AR1011 Pin Description

M1 Connect M1 to V

TX Transmit to host

RX Receive from host

SDO Connect SDO to V

UART communication is fixed at 9600 baud rate, 8N1 format.

Sleep mode will cause the TX line to drop low, which may appear as a 0x00 byte sent from the controller.

DD to select UART communications

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NOTES:

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7.0 TOUCH REPORTING PROTOCOL

Touch coordinates are sent from the controller to the host system in a 5-byte data packet, which contains the X-axis coordinate, Y-axis coordinate, and a “Pen-Up/ Down” touch status.

The range for X-axis and Y-axis coordinates is from 04095 (12-bit). The realized resolution is 1024, and bits X1:X0 and Y1:Y0 are zeros.

It is recommended that applications be developed to read the 12-bit coordinates from the packet and use them in a 12-bit format. This enhances the application robustness, as it will work with either 10 or 12 bits of coordinate information.

The touch coordinate reporting protocol is shown below in Tab le 7 -1 .

TABLE 7-1: TOUCH COORDINATE REPORTING PROTOCOL

Byte # Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

1 1 RRRRRRP

2 0 X6 X65 X4 X3 X2 X1 X0

3 0 0 0 X11 X10 X9 X8 X7

4 0 Y6 Y5 Y4 Y3 Y2 Y1 Y0

5 0 0 0 Y11 Y10 Y9 Y8 Y7

where:

• P: 0 Pen Up, 1 Pen Down

• R: Reserved

• X11-X0: X-axis coordinate

• Y11-Y0: Y-axis coordinate

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NOTES:

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8.0 CONFIGURATION REGISTERS

The Configuration registers allow application specific customization of the controller. The default values have been optimized for most applications and are automatically used, unless you choose to change them.

Unique sensors and/or product applications may benefit from adjustment of Configuration registers.

Note: Although most registers can be

configured for a value ranging from 0 to 255, using a value outside the specified range for the specific register may negatively impact performance.

8.1 Restoring Default Parameters

• AR1010/AR1020

The factory default settings for the Configuration registers can be recovered by writing a value of 0xFF to address 0x00 of the EEPROM, then cycling power.

• AR1011/AR1021

The factory default settings for the Configuration registers can be recovered by writing a value of 0xFF to addresses 0x01 and 0x29 of the EEPROM, then cycling power.

TABLE 8-1: CONFIGURATION REGISTERS

<Special Use> 0x00 <Non-Configurable> 0x58 0x58

<Special Use> 0x01 <Non-Configurable> 0x01 0x01

TouchThreshold 0x02 Value of: 0-255 0xC5 0xC5

SensitivityFilter 0x03 Value of: 0-255 0x04 0x04

SamplingFast 0x04 Value of: 1, 2, 4, 8, 16, 32, 64, 128 0x04 0x04

SamplingSlow 0x05 Value of: 1, 2, 4, 8, 16, 32, 64, 128 0x10 0x10

AccuracyFilterFast 0x06 Value of: 1-8 0x02 0x04

AccuracyFilterSlow 0x07 Value of: 1-8 0x08 0x08

SpeedThreshold 0x08 Value of: 0-255 0x04 0x04

<Special Use> 0x09 <Non-Configurable> 0x23 0x23

SleepDelay 0x0A Value of: 0-255 0x64 0x64

PenUpDelay 0x0B Value of: 0-255 0x80 0x80

TouchMode 0x0C PD2 PD1 PD0 PM1 PM0 PU2 PU1 PU0 0xB1 0xB1

TouchOptions 0x0D

CalibrationInset 0x0E 0x19 0x19

PenStateReportDelay 0x0F Value of: 0-40 0xC8 0xC8

<Special Use> 0x10 Value of: 0-255 0x03 0x03

TouchReportDelay 0x11 <Non-Configurable> 0x00 0x00

<Special Use> 0x12 Value of: 0-255 0x00 0x00

Configuration registers are defined as an Offset value from the Start address for the register group.

To read or write to a register, do the following:

• Issue the REGISTER_START_ADDRESS_REQUEST com- mand to obtain the Start address for the register group.

• Calculate the desired register’s absolute address by adding the register’s Offset value to Start address for the register group.

Address

Offset

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

— — — — — —48WCCE 0x00 0x00

• Issue the REGISTER_READ or REGISTER_WRITE command, using the calculated register’s absolute address.

Warning: Use of invalid register values will yield unpredictable results.

AR1010/

AR1020

Default

AR1011/

AR1021

Default

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8.2 Register Descriptions

8.2.1 TouchThreshold Register (OFFSET 0x02)

The TouchThreshold register sets the threshold for a touch condition to be detected as a touch. A touch is detected if it is below the TouchThreshold setting. Too small of a value might prevent the controller from accepting a real touch, while too large of a value might allow the controller to accept very light or false touch conditions. Valid values are as follows:

0 ≤ TouchThreshold ≤ 255

8.2.2 SensitivityFilter Register (OFFSET 0x03)

The SensitivityFilter register sets the level of touch sensitivity. A higher value is more sensitive to a touch (accepts a lighter touch), but may exhibit a less stable touch position. A lower value is less sensitive to a touch (requires a harder touch), but will provide a more stable touch position. Valid values are as follows:

0 ≤ SensitivityFilter ≤ 10

8.2.3 SamplingFast Register (OFFSET 0x04)

The SamplingFast register sets the level of touch measurement sample averaging, when touch movement is determined to be fast. See the SpeedThreshold register for information on the touch movement threshold. A lower value will provide for a higher touch coordinate reporting rate when touch movement is fast, but may exhibit more high-frequency random noise error in the touch position. A higher value will reduce the touch coordinate reporting rate when touch movement is fast, but will reduce high-frequency random noise error in the touch position. Valid values are as follows:

SamplingFast: <1, 4, 8, 16, 32, 64, 128>

Recommended Values: <4, 8, 16>

Higher values may improve accuracy with some sensors.

8.2.4 SamplingSlow Register (OFFSET 0x05)

The SamplingSlow register sets the level of touch measurement sample averaging, when touch movement is slow. See the SpeedThreshold register for information on the touch movement threshold. A lower value will increase the touch coordinate reporting rate when the touch motion is slow, but may exhibit a less stable more jittery touch position. A higher value will decrease the touch coordinate reporting rate when the touch motion is slow, but will provide a more stable touch position. Valid values are as follows:

SamplingSlow: 1, 2, 4, 8, 16, 32, 64, 128

8.2.5 AccuracyFilterFast Register (OFFSET 0x06)

The AccuracyFilterFast register sets the level of an accuracy enhancement filter, used when the touch movement is fast. See the SpeedThreshold register for information on the touch movement threshold. A lower value will provide better touch coordinate resolution when the touch motion is fast, but may exhibit more low-frequency noise error in the touch position. A higher value will reduce touch coordinate resolution when the touch motion is fast, but will reduce low-frequency random noise error in the touch position. Valid values are as follows:

1 ≤ AccuracyFilterFast ≤ 8

Higher values may improve accuracy with some sensors.

8.2.6 AccuracyFilterSlow Register (OFFSET 0x07)

The AccuracyFilterSlow register sets the level of an accuracy enhancement filter, used when the touch movement is slow. See the SpeedThreshold register for information on the touch movement threshold. A lower value will provide better touch coordinate resolution when the touch motion is slow, but may exhibit more low-frequency noise error in the touch position. A higher value will reduce touch coordinate resolution when the touch motion is slow, but will reduce low-frequency random noise error in the touch position. Valid values are as follows:

1 ≤ AccuracyFilterSlow ≤ 8

8.2.7 SpeedThreshold Register (OFFSET 0x08)

The SpeedThreshold register sets the threshold for touch movement to be considered as slow or fast. A lower value reduces the touch movement speed that will be considered as fast. A higher value increases the touch movement speed that will be considered as fast. Valid values are as follows:

0 ≤ SpeedThreshhold ≤ 255

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8.2.8 SleepDelay Register (OFFSET 0x0A)

The SleepDelay register sets the time duration with no touch or command activity that will cause the controller to enter a low-power Sleep mode. Valid values are as follows:

0 ≤ SleepDelay ≤ 255

Sleep Delay Time = SleepDelay * 100 ms; when SleepDelay > 0

A value of zero disables the Sleep mode, such that the controller will never enter low-power Sleep mode.

A touch event will wake the controller from low-power Sleep mode and start sending touch reports. Communications sent to the controller will wake it from the lowpower Sleep mode and initiate action to the command.

8.2.9 PenUpDelay Register (OFFSET 0x0B)

The PenUpDelay register sets the duration of a pen-up event that the controller will allow, without sending a pen-up report for the event. The delay time is started upon detecting a pen-up condition.

If a pen down is reestablished before the delay time expires, then pen-down reports will continue without a pen up being sent. This effectively debounces a touch event in process.

A lower value will make the controller more responsive to pen ups, but will cause more touch drop outs with a lighter touch. A higher value will make the controller less responsive to pen ups, but will reduce the number of touch drop outs with a lighter touch. Valid values are as follows:

0 ≤ PenUpDelay ≤ 255

Pen-up Delay Time ≈ PenUpDelay * 240 μs

8.2.10 TouchMode Register (OFFSET 0x0C)

The TouchMode register configures the action taken for various touch states.

There are three states of touch for the controller’s touch reporting action which can be independently controlled.

Touch States:

1. Pen Down (initial touch)

User defined 0-3 touch reports, with selectable pen states.

2. Pen Movement (touch movement after initial touch)

User defined no-touch reports or streaming touch reports, with selectable pen states.

3. Pen Up (touch release)

User defined 0-3 touch reports, with selectable pen states.

Every touch report includes a “P” (Pen) bit that indicates the pen state.

• Pen Down: P = 1

• Pen Up: P = 0

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REGISTER 8-1: TouchMode REGISTER FORMAT

R/W R/W R/W R/W R/W R/W R/W R/W

PD2 PD1 PD0 PM1 PM0 PU2 PU1 PU0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

bit 7-5 PD<2:0>: Pen-Down State bits (action taken upon pen down).

000 = No touch report 001 = Touch report with P=0 010 = Touch report with P=1 011 = Touch report with P=1, then touch report with P=0 100 = Touch report with P=0, then touch report with P=1, then touch report with P=0 101 = Touch report with P=0, then touch report with P=1

bit 4-3 PM<1:0>: Pen Movement State bits (action taken upon pen movement).

00 = No touch report 01 = Touch report with P=0 10 = Touch report with P=1

bit 2-0 PU<2:0>: Pen-Up State bits (action taken upon pen up).

A couple of typical setup examples for the TouchMode are as follows:

• Report a pen down P=1 on initial touch, followed by reporting a stream of pen downs P=1 during the touch, followed by a final pen up P=0 on touch release. TouchMode = 0b01010001 = 0x51

• Report a pen up P=0 then a pen down P=1 on initial touch, followed by reporting a stream of pen downs P=1 during the touch, followed by a final pen up P=0 on touch release. TouchMode = 0b10110001 = 0xB1

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Location of Calibration Targets presented during Calibration.

12.5% of Full Scale

8.2.11 TouchOptions Register (OFFSET 0x0D)

The TouchOptions register contains various “touch” related option bits.

REGISTER 8-2: TouchOptions REGISTER

U-0 U-0 U-0 U-0 U-0 U-0 R/W R/W

— — — — — — 48W CCE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

bit 7-2 Unimplemented: Read as ‘0’

bit 1 48W: 4-Wire or 8-Wire Sensor Selection bit

1 = Selects 8-wire Sensor Operating mode 0 = Selects 4-wire Sensor Operating mode

bit 0 CCE: Calibrated Coordinates Enable bit

1 = Enables calibrated coordinates, if the controller has been calibrated 0 = Disables calibrated coordinates

Note: A 4-wire touch sensor will not work if the

48W Configuration bit is incorrectly defined as 1, which selects 8-wire.

An 8-wire touch sensor will provide basic operation if the 48W Configuration bit is incorrectly defined as 0, which selects 4wire. However, the benefit of the 8-wire sensor will only be realized if the 48W Configuration bit is correctly defined as 1, selecting 8-wire.

8.2.12 CalibrationInset Register (OFFSET 0x0E)

The CalibrationInset register defines the expected position of the calibration points, inset from the perimeter of the touch sensor’s active area, by a percentage of the full scale dimension.

This allows for the calibration targets to be placed inset from edge to make it easier for a user to touch them.

The CalibrationInset register value is only used when the CALIBRATION_MODE command is issued to the controller. In Calibration mode, the controller will extrapolate the calibration point touch report values by the defined CalibrationInset percentage to achieve full scale.

A software application that issues the CALIBRATION_MODE command must present the displayed calibration targets at the same inset percentage as defined in this CalibrationInset register.

Valid values are as follows:

0 ≤ CalibrationInset ≤ 40

Calibration Inset = (CalibrationInset/2) %, Range of 020% with 0.5% resolution

For example, CalibrationInset = 25 (0x19) yields a calibration inset of (25/2) or 12.5%. During the calibration procedure, the controller will internally extrapolate the calibration point touch values in Calibration mode by

12.5% to achieve full scale.

FIGURE 8-1:

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8.2.13 PenStateReportDelay Register (OFFSET 0x0F)

The PenStateReportDelay register sets the delay time between sending of sequential touch reports for the “Pen-Down” and “Pen-Up” Touch mode states. See

Section 8.2.10 “TouchMode Register (offset 0x0C)”

for touch modes.

For example, if “Pen-Up” state of the TouchMode register is configured to send a touch report with P=1, followed by a touch report with P=0, then this delay occurs between the two touch reports. This provides some timing flexibility between the two touch reports that may be desired in certain applications. Valid values are as follows.

0 ≤ PenStateReportDelay ≤ 255

Pen State Report Delay Time = PenStateReportDelay * 50 μs

8.2.14 TouchReportDelay Register (OFFSET 0x11)

The TouchReportDelay register sets a forced delay time between successive touch report packets. This allows slowing down of the touch report rate, if desirable for a given application. For example, a given application may not need a high rate of touch reports and may want to reduce the overhead used to service all of the touch reports being sent. In this situation, increasing the value of this register will reduce the rate at which the controller sends touch reports. Valid values are as follows:

0 ≤ TouchReportDelay ≤ 255

Touch Report Delay Time ≈ TouchReportDelay * 500 μs

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9.0 COMMANDS

9.1 Sending Commands

9.1.1 COMMAND SEND FORMAT

The controller supports application-specific configuration commands as shown in Tab le 9 - 1, below.

TABLE 9-1: COMMAND SEND FORMAT

Byte # Name Value Description

1 Header 0x55 Header (mark beginning of command packet)

2 Size 0x<> Size, # of bytes following this byte

3 Command 0x<> Command ID

4 Data 0x<> Data, if applicable for the command

: Data 0x<> Data, if applicable for the command

To ensure command communication is not interrupted by touch activity, it is recommended that the controller touch is disabled, prior to other commands. This can be done as follows:

1. Send DISABLE_TOUCH command

2. Wait 50 ms

3. Send desired commands

4. Send ENABLE_TOUCH command

9.1.2 COMMAND RESPONSE

A received command will be responded to as seen in

Table 9-2 below.

TABLE 9-2: COMMAND RESPONSE FORMAT

Byte # Name Value Description

1 Header 0x55 Header (mark beginning of command packet)

2 Size 0x<> Size, # of bytes following this byte

3 Status 0x<> Status

4 Command 0x<> Command ID

5 Data 0x<> Data, if applicable for the command

: Data 0x<> Data, if applicable for the command

The “Status” value within the response packet should be one of the following (See Table 9-3):

TABLE 9-3: COMMAND RESPONSE

STATUS VALUES

Status Value Description

0x00 Success

0x01 Command Unrecognized

0x03 Header Unrecognized

0x04 Command Time Out (exceeded ~100

ms)

0xFC Cancel Calibration mode

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9.1.3 DISABLE TOUCH BEFORE SENDING SUBSEQUENT COMMANDS

The AR1000 does not support full duplex communications. It cannot send touch reports to the host simultaneously with receiving commands from the host.

Disable AR1000 touch reporting prior to sending any other command(s), then re-enable touch reporting when complete with executing other commands.

1. Send the DISABLE_TOUCH command.

Check for expected command response.

2. Send a desired command.

Check for expected command response.

3. Repeat at step 2 if another command is to be

sent.

4. Send the ENABLE_TOUCH command.

Check for expected command response.

9.1.4 CONFIRM COMMAND IS SENT

Confirm each command sent to the AR1000, prior to issuing another command, to ensure it is executed. This is accomplished by evaluating the AR1000 response to a command that has been sent to it.

Check for each of the following five conditions to be met (See Ta bl e 9 -4 ).

TABLE 9-4: COMMAND RESPONSE ERROR CONDITIONS

Condition Response Byte Description

Header 1 Header 0x55 value is expected

Size 2 Size 0x<> value to match what is expected for command sent

Status 3 Status 0x00 “success” value is expected

ID 4 Command ID 0x<> value to match what is expected (ID of sent command)

Data 5 to end Data byte count to match what is expected for command sent

0x<> represents a value that is dependent on the command.

An error has occurred if no response is received at all or if any of the above conditions are not met in the response from the AR1000. If an error condition occurs, delay for a period of ~50 ms then send the same command again.

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9.2 AR1000 Commands

TABLE 9-5: COMMAND SET SUMMARY

Command

Val ue

0x10 GET_VERSION

0x12 ENABLE_TOUCH

0x13 DISABLE_TOUCH

0x14 CALIBRATE_MODE

0x20 REGISTER_READ

0x21 REGISTER_WRITE

0x22 REGISTER_START_ADDRESS_REQUEST

0x23 REGISTERS_WRITE_TO_EEPROM

0x28 EEPROM_READ

0x29 EEPROM_WRITE

0x2B EEPROM_WRITE_TO_REGISTERS

9.3 AR1000 Command Descriptions

9.3.1 GET_VERSION – 0x10

Controller will return version number and type.

Send: <0x55><0x01><0x10>

Receive: <0x55><0x05><Response><0x10><Ver-

sion High><Version Low><Type>

where <Type>

Command Description

REGISTER 9-1: GET_VERSION <TYPE> FORMAT

R/W R/W R/W R/W R/W R/W R/W R/W

RS1 RS0 TP5 TP4 TP3 TP2 TP1 TP0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

bit 7-6 RS<1:0>: Resolution of Touch Coordinates bits

00 = 8-bit

01 = 10-bit

10 = 12-bit

bit 5-0 TP<5:0>: Type of Controller bits

001010 = ARA10

9.3.2 ENABLE_TOUCH – 0x12

Controller will send touch coordinate reports for valid touch conditions.

Send: <0x55><0x01><0x12>

Receive: <0x55><0x02><Response><0x12>

9.3.3 DISABLE_TOUCH – 0x13

Controller will not send any touch coordinate reports. A touch will, however, still wake-up the controller if asleep.

Send: <0x55><0x01><0x13>

Receive: <0x55><0x02><Response><0x13>

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

Touch Sensor

Upper Left

Upper Right

Lower RightLower Left

9.3.4 CALIBRATE – 0x14

Enter Calibration mode. This instructs the controller to enter a mode of accepting the next four touches as the calibration point coordinates. See Section 10.1 “Cali-

bration of Touch Sensor with Controller” for an

example.

Completion of Calibration mode will automatically store the calibration point coordinates in on-board controller memory and set (to 1) the CCE bit of the TouchOptions register. This bit enables the controller to report touch coordinates that have been processed with the previously collected calibration data.

To provide for proper touch orientation, the four sequential calibration touches must be input in the physical order on the touch sensor, as shown in

Figure 9-1.

FIGURE 9-1: CALIBRATION ROUTINE

SEQUENCE

Upon completion, the controller’s register values and calibration data are stored to the EEPROM.

The Calibration mode will be cancelled by sending any command before the mode has been completed. If the calibration is canceled, the controller response may appear incorrect or incomplete. This is expected behavior.

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9.3.4.1 AR1010/AR1020 Calibrate Response

Send: <0x55><0x02><0x14><Calibration Type>

Calibration Type

0x04 4 point

Receive: <0x55><0x02><0x00><0x14> for initial command response

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #1

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #2

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #3

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #4

A successful CALIBRATE command results in 5 response packets being sent to the host.

Once the response has been received for the completed 4 implemented prior to sending any commands to the controller. This one second delay insures all data has been completely written to the EEPROM.

target, a delay of one second must be

Description

9.3.4.2 AR1011/AR1021 Calibrate Response

Send: <0x55><0x02><0x14><Calibration Type>

Calibration Type

0x04 4 point

Receive: <0x55><0x02><0x00><0x14> for initial command response

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #1

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #2

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #3

<0x55><0x02><0x00><0x14> Response for touch of Calibration point #4

<0x55><0x02><0x00><0x14> Response after EEPROM has been written

A successful CALIBRATE command results in six response packets being sent to the host.

Description

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9.3.4.3 Calibration Data Encoded and Stored in EEPROM

System integrators may prefer to pre-load a calibration into their design. This allows the user to properly navigate to the calibration routine icon or shortcut without the use of a mouse. This also addresses the need to calibrate each system individually before deploying it to the field.

Separator Upper Left (Node 1) Upper Right (Node 2) Lower Right (Node 3) Lower Left (Node 4) Flip State

XY X YX Y X Y

Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo Hi

Decode the above data to as follows:

1. Swap the order of stored low and high bytes for

a given coordinate.

2. Convert the 16-bit value (stored high and low

bytes) from hexadecimal to decimal.

3. Divide the result by 64 to properly rescale the

16-bit stored value back to a 10-bit significant coordinate.

Example of Low = 0x40 and High = 0xF3:

Swap: 0xF340

Hex to Decimal: 62272

Divide by 64: 973

The raw touch coordinates, decoded by the controller, for each of the four calibration touches are extrapolated if CalibrationInset was non-zero. The four coordinate pairs are then re-oriented, if required, such that the upper left corner is the minimum (X,Y) “origin” value pair and the lower right corner is the maximum (X,Y) value pair.

Coordinates are 10-bit significant values, scaled to 16-bit and stored in a High (Hi) and Low (Lo) byte pair.

REGISTER 9-2: Flip State Byte

U-0 U-0 U-0 U-0 U-0 R/W R/W R/W

— — — — — XYFLIP XFLIP YFLIP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

bit 7-3 Unimplemented: Read as ‘0’

bit 2 XYFLIP: X and Y Axis Flip bit

1 = X and Y axis are flipped 0 = X an Y axis are not flipped

bit 1 XFLIP: X-Axis Flip bit

1 = X-axis flipped 0 = X-axis not flipped

bit 0 YFLIP:Y-Axis Flip bit

1 = Y-axis flipped 0 = Y-axis not flipped

For storing desired calibration values to the EEPROM:

• AR1010/AR1020 (See Section 9.3.12 “EEPROM

Map”).

• AR1011/AR1021 (See Section 9.3.12 “EEPROM

Map” and Section 10.2 “AR1011/AR1021 Storing Default Calibration Values to EEPROM”).

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9.3.5 REGISTER_READ – 0x20

Reads a value from a controller register location. This can be used to determine a controller configuration setting.

Configuration registers are defined as an Offset value from the Start address for the register group. Read a register as follows:

Issue the

1. command to obtain the Start address for the register group

2. Calculate the desired register’s absolute address by adding the register’s Offset value to Start address for the register group.

3. Issue this follows, using the calculated register ’s absolute address:

Send: <0x55><0x04><0x20><Register Address

Receive: <0x55><0x02 + # of Registers

The AR1000 controller will ignore the value entered for the Register Address High Byte. However, 0x00 is recommended to safeguard against any possible future product development.

REGISTER_START_ADDRESS_REQUEST

REGISTER_READ

High byte><Register Address Low byte><# of Registers to Read>

# of Registers to Read: 0x01 thru 0x08

Read><Response><0x20><Register value>…<Register value>

command, as

9.3.6 REGISTER_WRITE – 0x21

Write a value to a controller register location. This can be used to change a controller configuration setting.

Configuration registers are defined as an Offset value from the Start address for the register group. Write a register as follows:

Issue the

1. command to obtain the Start address for the register group.

2. Calculate the desired register’s absolute address by adding the register’s Offset value to Start address for the register group.

3. Issue this REGISTER_WRITE command, as follows, using the calculated register ’s absolute address:

Send: <0x55><0x04 + # Registers to

Receive: <0x55><0x02><Response><0x21>

REGISTER_START_ADDRESS_REQUEST

Write><0x21><Register Address High byte><Register Address Low byte>

<# of Registers to Write><Data>…<Data>

# of Registers to Read: 0x01 thru 0x08

The AR1000 controller will ignore the value entered for the Register Address High Byte. However, 0x00 is recommended to safeguard against any possible future product development.

9.3.7

REGISTER_START_ADDRESS_REQUEST

– 0x22

Configuration registers are defined as an Offset value from the Start address for the register group. This command returns the Start address for the register group.

Send: <0x55><0x01><0x22>

Receive:

<0x55><0x03><Response><0x22><Regi ster Start Address>

9.3.8 REGISTERS_WRITE_TO_EEPROM – 0x23

Save Configuration register values to EEPROM. This allows the controller to remember configurations settings through controller power cycles.

Send: <0x55><0x01><0x23>

Receive: <0x55><0x02><Response><0x23>

9.3.9 EEPROM_READ – 0X28

The controller has 256 bytes of on-board EEPROM.

• The first 128 bytes (address range 0x00-0x7F)

are reserved by the controller for the Configuration register settings and calibration data.

• The second 128 bytes (address range

0x80-0xFF) are provided for the user’s application, if desired.

This command provides a means to read values from the EEPROM.

Send: <0x55><0x04><0x28><EEPROM Address

High byte><EEPROM Address Low byte><# of EEPROM to Read>

# of Registers to Read: 0x01 thru 0x08

Receive: <0x55><0x02 + # EEPROM

Read><Response><0x28><EEPROM value>…<EEPROM value>

The AR1000 controller will ignore the value entered for the EEPROM Address High Byte. However, 0x00 is recommended to safeguard against any possible future product development.

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9.3.10 EEPROM_WRITE – 0x29

The controller has 256 bytes of on-board EEPROM.

This command provides a means to write values to the user space within the EEPROM.

• The first 128 bytes (address range 0x00-0x7F) are reserved by the controller for the Configuration register settings and calibration data. Only the Register Write to EEPROM command should be used to write Configuration registers to EEPROM. Failure to use the Register Write command to save Configuration registers to EEPROM may result in failures or reverting to previously stored Configuration register values.

• The second 128 bytes (address range 0x80-0xFF) are provided for the user’s application, if desired.

Warning: ONLY write to user EEPROM addresses of

0x80-0xFF.

One of the following actions is required for

EEPROM changes to be used by the controller:

• The controller power must be cycled from OFF to ON or

• Issue the

EEPROM_WRITE_TO_REGISTERS command.

Write to EEPROM as follows:

Send: <0x55><0x04 + # EEPROM to

Write><0x29><EEPROM Address High byte><EEPROM Address Low byte>

<# of EEPROM to Write><Data>…<Data>

# of Registers to Read: 0x01 thru 0x08

Receive: <0x55><0x02><Response><0x29>

The AR1000 controller will ignore the value entered for the EEPROM Address High Byte. However, 0x00 is recommended to safeguard against any possible future product development.

9.3.11 EEPROM_WRITE_TO_REGISTERS – 0x2B

Write applicable EEPROM data to Configuration registers. This will cause the controller to immediately begin using changes made to EEPROM stored Configuration register values. A power cycle of the controller will automatically cause the controller to use changes made to the EEPROM stored Configuration register values, without the need for issuing this command. This command eliminates the need for the power cycle.

Send: <0x55><0x01><0x2B>

Receive: <0x55><0x02><Response><0x2B>

9.3.12 EEPROM MAP

The first 128 bytes in address range 0x00:0x7F are reserved by the controller for the Configuration register settings and calibration data. The mapping of data in this reserved controller space of the EEPROM may change over different revisions within the product lifetime.

The EEPROM_WRITE command must not be used to write directly to the lower 128 bytes of the controller EEPROM space of 0x00:0x7F.

The second 128 bytes in address range 0x80:0xFF are provided for the user’s application, if desired.

TABLE 9-6: AR1010/AR1020 EEPROM

AND REGISTER MAP

EEPROM Address Function

0x00 <Special Use>

0x01 <Special Use>

0x02 <Special Use>

0x03 Touch Threshold

0x04 Sensitivity Filter

0x05 Sampling Fast

0x06 Sampling Slow

0x07 Accuracy Filter Fast

0x08 Accuracy Filter Slow

0x09 Speed Threshold

0x0A <Special Use>

0x0B Sleep Delay

0x0C Pen-Up Delay

0x0D Touch Mode

0x0E Touch Options

0x0F Calibration Inset

0x10 Pen State Report Delay

0x11 <Reserved>

0x12 Touch Report Delay

0x13 <Special Use>

0x14 Data Block Separator

0x15 Calibration UL X-low

0x16 Calibration UL X-high

0x17 Calibration UL Y-low

0x18 Calibration UL Y-high

0x19 Calibration UR X-low

0x1A Calibration UR X-high

0x1B Calibration UR Y-low

0x1C Calibration UR Y-high

0x1D Calibration LR X-low

0x1E Calibration LR X-high

0x1F Calibration LR Y-low

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TABLE 9-6: AR1010/AR1020 EEPROM

AND REGISTER MAP

EEPROM Address Function

0x20 Calibration LR Y-high

0x21 Calibration LL X-low

0x22 Calibration LL X-high

0x23 Calibration LL Y-low

0x24 Calibration LL Y-high

0x25 Calibration Flip State

0x26:0x7E <Special Use>

0x7F End of Controller Space

0x80:0xFF User Space

TABLE 9-7: AR1011/AR1021 EEPROM

AND REGISTER MAP

EEPROM Address Function

0x00 Not used

0x01 Configuration Registers –

Block Key

0x02 <Special Use>

0x03 <Special Use>

0x04 Touch Threshold

0x05 Sensitivity Filter

0x06 Sampling Fast

0x07 Sampling Slow

0x08 Accuracy Filter Fast

0x09 Accuracy Filter Slow

0x0A Speed Threshold

0x0B <Special Use>

0x0C Sleep Delay

0x0D Pen-Up Delay

0x0E Touch Mode

0x0F Touch Options

0x10 Calibration Inset

0x11 Pen State Report Delay

0x12 <Special Use>

0x13 Touch Report Delay

0x14 <Special Use>

0x15 Configuration Registers –

Checksum

0x16 Calibration - Block Key

0x17 Calibration UL X-low

0x18 Calibration UL X-high

0x19 Calibration UL Y-low

0x1A Calibration UL Y-high

0x1B Calibration UR X-low

0x1C Calibration UR X-high

TABLE 9-7: AR1011/AR1021 EEPROM

AND REGISTER MAP

EEPROM Address Function

0x1D Calibration UR Y-low

0x1E Calibration UR Y-high

0x1F Calibration LR X-low

0x20 Calibration LR X-high

0x21 Calibration LR Y-low

0x22 Calibration LR Y-high

0x23 Calibration LL X-low

0x24 Calibration LL X-high

0x25 Calibration LL Y-low

0x26 Calibration LL Y-high

0x27 Calibration Flip State

0x28 Calibration – Checksum

0x29:0x50 <Special Use>

0x51:0x7F <Reserved>

0x80:0xFF User Space

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NOTES:

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Touch and

Release Target

Touch and

Release Target

10.0 APPLICATION NOTES

10.1 Calibration of Touch Sensor with Controller

The reported coordinates from a touch screen controller are typically calibrated to the application’s video display. The task is often left up to the host to perform. This controller provides a feature for it to send coordinates that have already been calibrated, rather than the host needing to perform this task. If enabled, the feature will apply pre-collected 4-point calibration data to the reported touch coordinates. Calibration only accounts for X and Y directional scaling. It does not correct for angular errors due to rotation of the touch sensor on the video display.

The calibration process can be cancelled at anytime by sending a command to the controller.

Upon completion of the calibration process, the calibration data is automatically stored to the EEPROM and “Calibrated Coordinates” is enabled.

The process of “calibration” with the controller is described below.

1. Disable touch reporting by issuing <Disable

Touch> command.

Send: <0x55><0x01><0x13>

Receive: <0x55><0x02><Response><0x13>

2. Get register group Start address by issuing

REGISTER_START_ADDRESS_REQUEST

command.

A register Start address of 0x20 is used below, for this example.

Send: <0x55><0x01><0x22>

Receive: <0x55><0x03><0x00><0x22><0x20>

3. Calculate the CalibrationInset register’s address

by adding its offset value of 0x0E to the register group Start address of 0x20.

4. Calculate the desired value for the CalibrationIn-

set register.

A Calibration Inset of 12.5% is used below for this example.

CalibrationInset = 2 * Desire Calibration Inset % = 2 *

12.5 = 25 = 0x19

5. Set the Calibration Inset by writing the desired value to the CalibrationInset register.

Send:<0x55><0x05><0x21><0x00><0x2E><0x01

><0x19>

Receive: <0x55><0x02><0x00><0x21>

6. Issue the CALIBRATE_MODE command.

Send: <0x55><0x02><0x14><0x04>

Receive: <0x55><0x02><0x00><0x14>

7. Software must display the first calibration point target in the upper left quadrant of the display and prompt the user to touch and release the target.

FIGURE 10-1: SUGGESTED TEXT FOR

FIRST CALIBRATION TARGET

8. Wait for the user to touch and release the first calibration point target. Do this by looking for a controller response of:

<0x55><0x02><0x00> <0x14>

9. Software must display the second calibration point target in the upper right quadrant of the display and prompt the user to touch and release the target.

FIGURE 10-2: SUGGESTED TEXT FOR

SECOND CALIBRATION TARGET

10. Wait for the user to touch and release the second calibration point target. Do this by looking for a controller response of:

<0x55><0x02><0x00><0x14>

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Touch and

Release Target

Touch and

Release Target

11. Software must display the third calibration point target in the lower right quadrant of the display and prompt the user to touch and release the target.

FIGURE 10-3: SUGGESTED TEXT FOR

THIRD CALIBRATION TARGET

12. Wait for the user to touch and release the third calibration point target. Do this by looking for a controller response of:

<0x55><0x02><0x00><0x14>

13. Software must display the fourth calibration point target in the lower left quadrant of the display and prompt the user to touch and release the target.

FIGURE 10-4: SUGGESTED TEXT FOR

FOURTH CALIBRATION TARGET

14. Wait for the user to touch and release the fourth calibration point target. Do this by looking for a controller response of: <0x55><0x02><0x00><0x14>

15. Wait for the controller to correctly write calibration data into EEPROM

• AR1010/AR1020: Wait one second for data to

be stored into EEPROM

• AR1011/AR1021: Wait for a controller response of <0x55><0x02><0x00><0x14>

16. Enable touch reporting by issuing ENABLE_TOUCH command.

Send: <0x55><0x01><0x12>

Receive: <0x55><0x02><Response><0x12>

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10.2 AR1011/AR1021 Storing Default Calibration Values to EEPROM

If you wish to implement fixed calibration values, pre-loaded into the AR1000 EEPROM, then the following procedure must be followed (See

Section 10.2.1 “Preparation for Fixed Calibration Values”).

An example of calculating the checksum is shown below (See Tab le 1 0- 1).

10.2.1 PREPARATION FOR FIXED

CALIBRATION VALUES

Determine if fixed calibration values are suitable for your application and determine your desired values.

Calculate a checksum for your custom data set. See

Section 9.3.4.3 “Calibration Data Encoded and Stored in EEPROM” for additional details regarding

calibration data format.

TABLE 10-1: CHECKSUM CALCULATION EXAMPLE

Description Value Operation Checksum Result

Seed 0x45 n/a 0x45

Block Key 0x55 0x45 + 0x55 = 0x9A

Upper Left X Low byte 0x06 0x9A + 0x06 = 0xA0

Upper Left X High byte 0x1B 0xA0 + 0x1B = 0xBB

Upper Left Y Low byte 0xA5 0xBB + 0xA5 = 0x60

Upper Left Y High byte 0x08 0x60 + 0x08 = 0x68

Upper Right X Low byte 0x13 0x68 + 0x13 = 0x7B

Upper Right X High byte 0xDF 0x7B + 0xDF = 0x5A

Upper Right Y Low byte 0xF4 0x5A + 0xF4 = 0x4E

Upper Right Y High byte 0x0B 0x4E + 0x0B = 0x59

Lower Right X Low byte 0x98 0x59 + 0x98 = 0xF1

Lower Right X High byte 0xE4 0xF1 + 0xE4 = 0xD5

Lower Right Y Low byte 0x1E 0xD5 + 0x1E = 0xF3

Lower Right Y High byte 0xEC 0xF3 + 0xEC = 0xDF

Lower Left X Low byte 0xBF 0xDF + 0xBF = 0x9E

Lower Left X High byte 0x1A 0x9E + 0x1A = 0xB8

Lower Left Y Low byte 0x32 0xB8 + 0x32 = 0xEA

Lower Left Y High byte 0xE7 0xEA + 0xE7 = 0xD1

Flip State 0x01 0xD1 + 0x01 = 0xD2

Checksum 0xD2

The Checksum is an 8-bit value calculated by successive additions with overflow ignored, as shown below.

Checksum = 0x45

For each of the 18 calibration values, starting at the Block Key and ending with the Flip State

Checksum += Calibration value

Next Calibration value

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10.2.2 EXECUTION OF FIXED CALIBRATION VALUE LOADING

Follow error checking practices by checking the AR1000 responses to issued commands.

1. Send the AR1000 DISABLE_TOUCH command.

2. Use the AR1000 EEPROM_WRITE command

multiple times to write the following to the AR1000 EEPROM.

a. Block Key 0x55 to address 0x16 b. Data set to addresses 0x17:0x27. See

Section 9.3.4.3 “Calibration Data Encoded and Stored in EEPROM” and Section 9.3.12 “EEPROM Map”.

c. Checksum for the data block to address

0x28

d. Mirror image of a, b and c from above to

address 0x3E:0x50

3. Set the CCE bit of the TouchOptions register.

This will enable the controller to use the calibration data on the next power boot. See

Section 10.2.3 “Configuring the CCE bit to Use Fixed Calibration Values” for additional

details on the CCE bit.

4. Send the AR1000 ENABLE_TOUCH (0x12)

command.

10.2.3 CONFIGURING THE CCE BIT TO USE FIXED CALIBRATION VALUES

The CCE bit of the TouchOptions Register (offset 0x0D) must be set to ‘1’ to enable the usage of the stored calibration values in EEPROM.

This should be completed before re-enabling the controller via the ENABLE_TOUCH command.

REGISTER 10-1: CCE BIT FORMAT

U-0 U-0 U-0 U-0 U-0 U-0 R/W R/W

— — — — — — 48W CCE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

bit 7-2 Unimplemented: Read as ‘0’

bit 1 48W: 4-Wire or 8-Wire Sensor Selection bit

1 = Selects 8-wire Sensor Operating mode 0 = Selects 4-wire Sensor Operating mode

bit 0 CCE: Calibrated Coordinates Enable bit

1 = Enables calibrated coordinates, if the controller has been calibrated 0 = Disables calibrated coordinates

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1. Send the DISABLE_TOUCH (0x13) command.

2. Send the

REGISTER_START_ADDRESS_REQUEST

(0x22) to determine the absolute address for TouchOptions Register.

3. Send the REGISTER_WRITE (0x21) command to set the CCE bit of the TouchOptions Register.

4. Send REGISTERS_WRITE_TO_EEPROM (0x23) command to have all current registers stored into EEPROM.

5. Send the AR1000 ENABLE_TOUCH (0x12) command.

The controller will use the stored calibration data after cycling power to the controller.

10.2.4 EEPROM_WRITE COMMAND TO

STORE DEFAULT CALIBRATION

The EEPROM_WRITE command is shown in this section. See Section 9.0 “Commands” for more command details.

<> = application specific value

Send to AR1000:

0x55 Header

0x<> Number of bytes to follow this one

0x29 Command ID

0x00 Desired EEPROM address to write high

byte. Always 0x00

0x<> Desired EEPROM address to write low

byte

0x<> Number of consecutive EEPROM

addresses to write (supports 0x01 to 0x08)

0x<> Value # 1 to write

0x<> Value # 2 to write, if applicable

0x<> Value # 3 to write, if applicable

0x<> Value # 4 to write, if applicable

0x<> Value # 5 to write, if applicable

0x<> Value # 6 to write, if applicable

0x<> Value # 7 to write, if applicable

0x<> Value # 8 to write, if applicable

10.2.5 QUALITY TEST

Although not required, a level of quality assurance can be added to the process by the application issuing multiple EEPROM_READ commands to the AR1000.

The response data from the EEPROM_READ commands would be tested by the application against the application’s desired data as a quality check.

10.2.6 EXAMPLE COMMAND SEQUENCE

An example eight command sequence for the entire process is shown below.

All values shown are in hexadecimal.

Calibration values are applications specific and have been symbolically represented as follows:

ULxL = Upper Left corner x-coordinate Low byte

LLyH = Lower Left corner y-coordinate High byte

DISABLE_TOUCH

Response from AR1000:

0x55 Header

0x02 Number of bytes to follow this one

0x00 Success response

0x29 Command ID

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

Disable Touch

Command: 55 01 13

Response: 55 020013

Write Calibration to EEPROM Image # 1

Command: 55 0C 29 00 16 08 55 ULxL ULxH ULyL ULyH URxL URxH URyL

Response: 55 020029

Command: 55 0C 29 00 1E 08 URyH LRxL LRxH LRyL LRyH LLxL LLxH LLyL

Response: 55 020029

Command: 55 07 29 00 26 03 LLyH FlipS Chksm

Response: 55 020029

Write Calibration to EEPROM Image # 2

Command: 55 0C 29 00 3E 08 55 ULxL ULxH ULyL ULyH URxL URxH URyL

Response: 55 020029

Command: 55 0C 29 00 46 08 URyH LRxL LRxH LRyL LRyH LLxL LLxH LLyL

Response: 55 020029

Command: 55 07 29 00 4E 03 LLyH FlipS Chksm

Response: 55 020029

Enable Use of Calibrated Data

Command: 55 01 22

Response: 55 030022<Start Address>

Command:

4/8-Wire 55 05 21 00 <Start Address + 0x0D> 01 01

5-Wire 55 05 21 00 <Start Address + 0x0D> 01 03

Response: 55 020021

Enable Touch

Command: 55 01 12

Response: 55 020012

DS41393B-page 50 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

11.0 ELECTRICAL SPECIFICATIONS

Absolute Maximum Ratings

Ambient temperature under bias.......................................................................................................-40°C to +125°C

Storage temperature ........................................................................................................................ -65°C to +150°C

Voltage on V

Voltage on all other pins with respect to V

Total power dissipation................................................................................................................................... 800 mW

Maximum current out of V

Maximum current into V

Input clamp current (V

Maximum output current sunk by any I/O pin.................................................................................................... 25 mA

Maximum output current sourced by any I/O pin .............................................................................................. 25 mA

† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.

† NOTICE: This device is sensitive to ESD damage and must be handled appropriately. Failure to properly handle and protect the device in an application may cause partial to complete failure of the device.

DD with respect to VSS .................................................................................................... -0.3V to +6.5V

SS pin .................................................................................................................... 300 mA

DD pin ....................................................................................................................... 250 mA

I < 0 or VI > VDD) 20 mA

(†)

SS ........................................................................... -0.3V to (VDD + 0.3V)

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 51

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

11.1 Minimum Operating Voltage

The AR1000 series controller will operate down to 2.5V ± 5%. Touch performance will be optimized by using the highest allowable voltage for the design.

The PICkit Serial included in the AR1000 Development kit supports 3V-5V range of operation.

11.2 AR1000 Electrical Characteristics

Operating Voltage: 2.5 ≤ VDD ≤ 5.25V

Function Pin Input Output

M1 M1 V

SS ≤ VIL ≤ 0.15*VDD

(0.25*VDD + 0.9V) ≤ VIH ≤ VDD

M2 M2 V

SS ≤ VIL ≤ 0.15*VDD

(0.25*VDD + 0.9V) ≤ VIH ≤ VDD

SCL/SCK SCL/SCK/TX V

SS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

TX SCL/SCK/TX — V

SDI SDI/SDA/RX VSS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

SDO SDO — V

—

SS ≤ VOL

(1)

≤ (1.2V – 0.15*VDD)

(1.25*VDD – 2.25V)

—

SS ≤ VOL

(1)

≤ (1.2V – 0.15*VDD)

(1.25*VDD – 2.25V)

(3)

≤ VOH

(3)

≤ VOH

(1)

≤ VDD

(1)

≤ VDD

(2)

SIQ SIQ — VSS ≤ VOL

SDA SDI/SDA/RX VSS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

RX SDI/SDA/RX V

SS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

SS SS V

SS ≤ VIL ≤ 0.2*VDD

0.8*VDD ≤ VIH ≤ VDD

Note 1: These parameters are characterized but not tested.

2: At 10 mA. 3: At -4 mA.

(1)

≤ (1.2V – 0.15*VDD)

(1.25*VDD – 2.25V)

Open-drain

—

(3)

≤ VOH

(1)

≤ VDD

(2)

DS41393B-page 52 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

* Standard PICmicro® device marking consists of Microchip part number, year code, week code and

traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP price.

Legend: XX...X Customer-specific information

Y Year code (last digit of calendar year) YY Year code (last 2 digits of calendar year) WW Week code (week of January 1 is week ‘01’) NNN Alphanumeric traceability code Pb-free JEDEC designator for Matte Tin (Sn) * This package is Pb-free. The Pb-free JEDEC designator ( )

can be found on the outer packaging for this package.

Note: In the event the full Microchip part number cannot be marked on one line, it will

be carried over to the next line, thus limiting the number of available characters for customer-specific information.

20-Lead SSOP (5.30 mm) Example

20-Lead SOIC (7.50 mm) Example

XXXXXXXXXXXX

YYWWNNN

XXXXXXXXXXXX XXXXXXXXXXXX

AR1021

I/SS

AR1021 I/SO

1042256

12.0 PACKAGING INFORMATION

12.1 Package Marking Information

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 53

Page 54

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

* Standard PICmicro® device marking consists of Microchip part number, year code, week code and

Legend: XX...X Customer-specific information

can be found on the outer packaging for this package.

Note: In the event the full Microchip part number cannot be marked on one line, it will

be carried over to the next line, thus limiting the number of available characters for customer-specific information.

20-Lead QFN (4x4x0.9 mm) Example

PIN 1

I/ML

1042256

AR1021

12.2 Package Marking Information (Continued)

DS41393B-page 54 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

12.3 Ordering

Note: The AR1011/AR1021 are recommended

for new designs. The AR1010/AR1020 are still supported and available, but are not recommended for new designs.

TABLE 12-1: ORDERING PART NUMBERS

Part Number

AR1011-I/ML UART -40°C to + 85°C QFN, 20 pin Tube

AR1011-I/SO UART -40°C to + 85°C SOIC, 20 pin Tube

AR1011-I/SS UART -40°C to + 85°C SSOP, 20 pin Tube

AR1011T-I/ML UART -40°C to + 85°C QFN, 20 pin T/R

AR1011T-I/SO UART -40°C to + 85°C SOIC, 20 pin T/R

AR1011T-I/SS UART -40°C to + 85°C SSOP, 20 pin T/R

AR1021-I/ML I

AR1021-I/SO I

AR1021-I/SS I2CTM/SPI -40°C to + 85°C SSOP, 20 pin Tube

AR1021T-I/ML I2CTM/SPI -40°C to + 85°C QFN, 20 pin T/R

AR1021T-I/SO I

AR1021T-I/SS I2CTM/SPI -40°C to + 85°C SSOP, 20 pin T/R

Communication

Typ e

2CTM

/SPI -40°C to + 85°C QFN, 20 pin Tube

2CTM

/SPI -40°C to + 85°C SOIC, 20 pin Tube

2CTM

/SPI -40°C to + 85°C SOIC, 20 pin T/R

Temp. Range Pin Package Packing

AR1010-I/ML UART -40°C to + 85°C QFN, 20 pin Tube

AR1010-I/SO UART -40°C to + 85°C SOIC, 20 pin Tube

AR1010-I/SS UART -40°C to + 85°C SSOP, 20 pin Tube

AR1010T-I/ML UART -40°C to + 85°C QFN, 20 pin T/R

AR1010T-I/SO UART -40°C to + 85°C SOIC, 20 pin T/R

AR1010T-I/SS UART -40°C to + 85°C SSOP, 20 pin T/R

2CTM

AR1020-I/ML I

/SPI -40°C to + 85°C QFN, 20 pin Tube

AR1020-I/SO I2CTM/SPI -40°C to + 85°C SOIC, 20 pin Tube

AR1020-I/SS I2CTM/SPI -40°C to + 85°C SSOP, 20 pin Tube

2CTM

AR1020T-I/ML I

/SPI -40°C to + 85°C QFN, 20 pin T/R

AR1020T-I/SO I2CTM/SPI -40°C to + 85°C SOIC, 20 pin T/R

AR1020T-I/SS I2CTM/SPI -40°C to + 85°C SSOP, 20 pin T/R

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 55

Page 56

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

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1RWHV

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KWWSZZZPLFURFKLSFRPSDFNDJLQJ

8QLWV 0,//,0(7(56

'LPHQVLRQ/LPLWV 0,1 120 0$;

1XPEHURI3LQV 1 

3LWFK H %6&

2YHUDOO+HLJKW $ ± ± 

0ROGHG3DFNDJH7KLFNQHVV $   

6WDQGRII $  ± ±

2YHUDOO:LGWK (   

0ROGHG3DFNDJH:LGWK (   

2YHUDOO/HQJWK '   

)RRW/HQJWK /   

)RRWSULQW / 5()

/HDG7KLFNQHVV F  ± 

)RRW$QJOH    

/HDG:LGWK E  ± 

NOTE 1

0LFURFKLS 7HFKQRORJ\ 'UDZLQJ &%

12.4 Package Details

The following sections give the technical details of the packages.

DS41393B-page 56 Preliminary  2009-2012 Microchip Technology Inc.

Page 57

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 57

Page 58

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

DS41393B-page 58 Preliminary  2009-2012 Microchip Technology Inc.

Page 59

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 59

Page 60

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

DS41393B-page 60 Preliminary  2009-2012 Microchip Technology Inc.

Page 61

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

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KWWSZZZPLFURFKLSFRPSDFNDJLQJ

8QLWV 0,//,0(7(56

'LPHQVLRQ/LPLWV 0,1 120 0$;

1XPEHURI3LQV 1 

3LWFK H %6&

2YHUDOO+HLJKW $   

6WDQGRII $   

&RQWDFW7KLFNQHVV $ 5()

2YHUDOO:LGWK ( %6&

([SRVHG3DG:LGWK (   

2YHUDOO/HQJWK ' %6&

([SRVHG3DG/HQJWK '   

&RQWDFW:LGWK E   

&RQWDFW/HQJWK /   

&RQWDFWWR([SRVHG3DG .  ± ±

EXPOSED

PAD

TOP VIEW

NOTE 1

BOTTOM VIEW

0LFURFKLS 7HFKQRORJ\ 'UDZLQJ &%

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 61

Page 62

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

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KWWSZZZPLFURFKLSFRPSDFNDJLQJ

DS41393B-page 62 Preliminary  2009-2012 Microchip Technology Inc.

Page 63

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

APPENDIX A: DATA SHEET

REVISION HISTORY

Revision A (07/2009)

Original release of this data sheet.

Revision B (03/2012)

Updated data sheet.

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 63

Page 64

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

APPENDIX B:

Modifying, removing or adding components may adversely affect touch performance.

Specific manufacturers and part numbers are provided only as a guide. Equivalents can be used.

TABLE B-1: BILL OF MATERIALS

Label Quantity Value Description Manufacturer Part Number

C1 1 10 uF Capacitor – Ceramic, 10 uF, 20%, 6.3V,

X7R, 0603

C2 1 0.1 uF Capacitor – Ceramic, 0.1 uF, 10%, 16V,

X7R, 0603

C3, C4, C5

D1-D8

R1 1 20 K Resistor – 20 K, 1/10W, 5%, 0603 Yageo America RC0603JR-0720KL

U1 1 N/A Touch controller IC Microchip AR1011 or AR1021

Note 1: C5 is only needed for 5-wire applications.

See Section 3.8 “ESD Considerations” and Section 3.9 “Noise Considerations” for important information regarding the capacitance of the controller schematic hardware.

(1)

2-3 0.01 uF Capacitor – Ceramic, 0.01 uF, 10%,

50V, X7R, 0603

(2)

2: D1-D8 are for ESD protection.

4-8 130W Diode – Bidirectional, 130W, ESD

Protection, SOD323

- 4-wire touch screen, use D1-D4

- 5-wire touch screen, use D1-D5

- 8-wire touch screen, use D1-D8

AVX 06036D106MAT2A

AVX 0603YC104KAT2A

AVX 06035C103KAT2A

NXP PESD5V0S1BA

DS41393B-page 64 Preliminary  2009-2012 Microchip Technology Inc.

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

INDEX

Numerics

4, 5, 8-Wire Sensor Selection .............................................12

4-Wire Sensor....................................................................... 7

4-Wire Touch Sensor Interface ...........................................12

5-Wire Sensor..................................................................... 10

5-Wire Touch Sensor Interface ...........................................13

8-Wire Sensor....................................................................... 9

8-Wire Touch Sensor Interface ...........................................14

Absolute Maximum Ratings ................................................51

Addressing..........................................................................18

Application Notes................................................................45

Applications...........................................................................5

AR1011/AR1021 Storing Default Calibration Values

to EEPROM ................................................................47

AR1020 Write Conditions.................................................... 19

Basics ................................................................................... 7

Basics of Resistive Sensors..................................................7

Calibration of Touch Sensor with Controller .......................45

Clock Stretching..................................................................19

Command Protocol .............................................................20

Commands.......................................................................... 35

Communication................................................................... 17

Communications ................................................................... 3

Configuration Registers ................................................25, 29

Customer Change Notification Service ............................... 67

Customer Notification Service............................................. 67

Customer Support ............................................................... 67

Data Flow............................................................................22

Device Overview................................................................... 5

Electrical Specifications ...................................................... 51

Errata ....................................................................................4

General ................................................................................. 7

Hardware ............................................................................ 11

I2C Hardware Interface....................................................... 17

I2C Pin Voltage Level Characteristics................................. 18

Internet Address.................................................................. 67

Main Schematic .................................................................. 11

Master Read Bit Timing ......................................................18

Master Write Bit Timing.......................................................19

Microchip Internet Web Site................................................67

Noise Considerations.......................................................... 15

Packaging........................................................................... 53

Marking................................................................. 53, 54

Power Requirements ............................................................ 3

Reader Response............................................................... 68

Restoring Default Parameters ............................................ 29

Revision History.................................................................. 63

Sending Commands ........................................................... 35

Sleep State ......................................................................... 20

Special Features................................................................... 3

SPI Bit Timing - General ..................................................... 23

SPI Communications.......................................................... 21

SPI Hardware Interface ...................................................... 21

SPI Pin Voltage Level Characteristics ................................ 22

Status LED ......................................................................... 15

Terminology.......................................................................... 7

Timing – Bit Details............................................................. 24

Touch Modes ........................................................................ 3

Touch Report Protocol........................................................ 20

Touch Report Protocol........................................................ 22

Touch Reporting Protocol ................................................... 27

Touch Resolution.................................................................. 3

Touch Sensor Support.......................................................... 3

UART Communications ...................................................... 25

Wake Pin ............................................................................ 15

WWW Address ................................................................... 67

WWW, On-Line Support ....................................................... 4

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 65

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AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

NOTES:

DS41393B-page 66 Preliminary  2009-2012 Microchip Technology Inc.

Page 67

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

THE MICROCHIP WEB SITE

Microchip provides online support via our WWW site at

www.microchip.com. This web site is used as a means

to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site contains the following information:

• Product Support – Data sheets and errata,

application notes and sample programs, design resources, user’s guides and hardware support documents, latest software releases and archived software

• General Technical Support – Frequently Asked

Questions (FAQ), technical support requests, online discussion groups, Microchip consultant program member listing

• Business of Microchip – Product selector and

ordering guides, latest Microchip press releases, listing of seminars and events, listings of Microchip sales offices, distributors and factory representatives

CUSTOMER CHANGE NOTIFICATION SERVICE

CUSTOMER SUPPORT

Users of Microchip products can receive assistance through several channels:

• Distributor or Representative

• Local Sales Office

• Field Application Engineer (FAE)

• Technical Support

• Development Systems Information Line

Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document.

Technical support is available through the web site at: http://microchip.com/support

Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest.

To register, access the Microchip web site at

www.microchip.com. Under “Support”, click on

“Customer Change Notification” and follow the registration instructions.

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 67

Page 68

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

TO: Technical Publications Manager

RE: Reader Response

Total Pages Sent ________

From:

Name

Company

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DS41393BAR1000 Series Resistive Touch Screen Controller

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DS41393B-page 68 Preliminary  2009-2012 Microchip Technology Inc.

Page 69

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

NOTES:

 2009-2012 Microchip Technology Inc. Preliminary DS41393B-page 69

Page 70

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11/29/11

DS41393B-page 70 Preliminary  2009-2012 Microchip Technology Inc.

Datasheet AR 1021, AR 1011 Datasheet

Special Features:

Power Requirements:

Touch Modes:

Touch Sensor Support:

Touch Resolution:

Touch Coordinate Report Rate:

Communications:

Table of Contents

Most Current Data Sheet

Errata

Customer Notification System

1.0 DEVICE OVERVIEW

FIGURE 1-1: BLOCK DIAGRAM

1.1 Applications

FIGURE 1-2: PIN DIAGRAM

TABLE 1-1: PIN DESCRIPTIONS

2.0 BASICS OF RESISTIVE SENSORS

2.1 Terminology

2.2 General

TABLE 2-1: SENSOR COMPARISON

2.3 4-Wire Sensor

FIGURE 2-1: 4-WIRE DECODING

2.4 8-Wire Sensor

FIGURE 2-2: 8-WIRE DECODING

2.5 5-Wire Sensor

FIGURE 2-3: 5-Wire Decoding

3.0 HARDWARE

3.1 Main Schematic

FIGURE 3-1: MAIN SCHEMATIC (SOIC/SSOP PACKAGE PINOUT)

3.2 4, 5, 8-Wire Sensor Selection

3.3 4-Wire Touch Sensor Interface

FIGURE 3-2: 4-WIRE TOUCH SENSOR INTERFACE

3.4 5-Wire Touch Sensor Interface

FIGURE 3-3: 5-WIRE TOUCH SENSOR INTERFACE

3.5 8-Wire Touch Sensor Interface

FIGURE 3-4: 8-WIRE TOUCH SENSOR INTERFACE

3.6 Status LED

FIGURE 3-5:

3.7 WAKE Pin

3.8 ESD Considerations

3.9 Noise Considerations

4.0 I2CTM COMMUNICATIONS

4.1 I2C Hardware Interface

TABLE 4-1: I2C HARDWARE INTERFACE

4.2 I2C Pin Voltage Level Characteristics

TABLE 4-2: I2C PIN VOLTAGE LEVEL CHARACTERISTICS

4.3 Addressing

TABLE 4-3: I2C DEVICE ID ADDRESS

4.4 Master Read Bit Timing

FIGURE 4-1: I2C MASTER READ BIT TIMING DIAGRAM

4.5 Master Write Bit Timing

FIGURE 4-2: I2C MASTER WRITE BIT TIMING DIAGRAM

4.6 Clock Stretching

4.7 AR1020 Write Conditions

4.8 Touch Report Protocol

FIGURE 4-3: I2C TOUCH REPORT PROTOCOL

4.9 Command Protocol

FIGURE 4-4: I2C COMMAND PROTOCOL

4.10 Sleep State

5.0 SPI COMMUNICATIONS

5.1 SPI Hardware Interface

TABLE 5-1: SPI HARDWARE INTERFACE

5.2 SPI Pin Voltage Level Characteristics

TABLE 5-2: SPI PIN VOLTAGE CHARACTERISTICS

5.3 Data Flow

5.4 Touch Report Protocol

FIGURE 5-1: SPI TOUCH REPORT PROTOCOL

5.5 Command Protocol

FIGURE 5-2: SPI TIMING DIAGRAM – COMMAND PROTOCOL (ENABLE_TOUCH)

5.6 SPI Bit Timing – General

FIGURE 5-3: SPI GENERAL BIT TIMING WAVEFORM

5.7 Timing – Bit Details

5.7.1 BIT RATE

FIGURE 5-4: SPI BIT TIMING – DETAIL

5.7.2 INTER-BYTE DELAY

5.7.3 BIT TIMING – DETAIL

TABLE 5-3: SPI BIT TIMING MIN. AND MAX. VALUES

6.0 UART COMMUNICATIONS

TABLE 6-1: UART HARDWARE INTERFACE