mTouch™ Projected Capacitive Touch Screen Sensing Theory of Operation
`
`TB3064
`
`Author:
`
`Todd O’Connor
`Microchip Technology Inc.
`
`INTRODUCTION
`Microchip's mTouch™ Projected Capacitive Touch
`Screen Sensing technology provides a readily accessi-
`ble, low cost, low power solution to facilitate implemen-
`tation of projected capacitive touch screen user
`interfaces.
`Among many other desirable characteristics, projected
`capacitive sensor technology can provide an easy to
`use, robust, and feature rich user touch interface. Ges-
`tures are an example of a feature that can be supported
`with this technology.
`A development kit (P/N DM160211) can be purchased
`at microchipDIRECT: www.microchipdirect.com. The
`source code is available royalty-free for use on
`Microchip PIC® MCUs.
`This document covers the theory of operation behind
`this exciting patent-pending technology.
`
`BASIC PROJECTED CAPACITIVE
`SENSOR
`There are number of different projected capacitive
`sensor constructions and various materials used for
`each. One of the sensor constructions consists of the
`following:
`
`• Two layers, each having a multitude of conductive
`electrodes arranged parallel to each other.
`• The layers are fixed in close proximity to each
`other and electrically insulated from each other.
`• The layers are oriented with their electrodes
`orthogonal to each other.
`A front view of an example sensor is shown in Figure 1,
`with 9 top layer electrodes represented in blue and 12
`bottom layer electrodes in red.
`
`FIGURE 1:
`
`EXAMPLE SENSOR –
`FRONT VIEW
`
`A cross sectional view of the example sensor is shown
`in Figure 2.
`
`FIGURE 2:
`
`EXAMPLE SENSOR – CROSS SECTIONAL VIEW
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` 2010 Microchip Technology Inc.
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`Electrodes
`The electrodes are the active conductive elements of
`the sensor. They are often made of Indium Tin Oxide
`(ITO) for its transparent and conductive properties.
`Another example for the electrodes could be copper on
`a rigid or flexible printed circuit board.
`Many electrode patterns can be used to create a
`projected capacitive sensor. The electrode pattern
`geometries are an important factor in the overall
`resolution and touch sensitivity of the sensor.
`A common pattern for the electrodes is a series of dia-
`monds interconnected with narrow “neck” sections.
`The pattern allows for interleaving of the diamonds on
`the front and back panel layers, such that only a small
`portion of the back panel electrodes are blocked by
`those on the front panel. This optimizes the presented
`electrode surface area (refer to Figure 3).
`
`FIGURE 4:
`
`SIMPLE CAPACITOR
`
`FIGURE 3:
`
`DIAMOND ELECTRODE
`PATTERN ALIGNMENT
`
`CAPACITANCE
`Capacitance is the ability of a material to store electrical
`charge. A simple capacitor model is two conductive
`plates held separated by an
`insulator (refer to
`Figure 4).
`
`Capacitance (farads) = k•ε0•(A/d)
`where ε0 = permittivity of free space = 8.854e – 12 F/m
`The value of capacitance is dependent on:
`• Surface area of the plates
`• Distance between the plates
`• Materials constant for the insulator between
`plates
`
`Capacitance of Touch
`The capacitance of touch is dependent on sensor
`design, sensor integration, touch controller design and
`the touch itself.
`Some examples of sensor properties that affect its
`capacitance are:
`• Front panel thickness
`• Electrode geometry and pitch
`• X,Y layer-to-layer spacing
`• Rear shielding
`
`The capacitance of the sensor and of the touch can
`vary significantly, based on the many variables. Some
`example values are shown in Table 1 to give an idea of
`scale for discussion.
`TABLE 1:
`TYPICAL PARASITIC AND
`TOUCH CAPACITANCE
`Capacitance
`Item
`100 pF
`Electrode Parasitic
`0.5 to 1.0 pF
`Strong Electrode Touch
`Weak Electrode Touch
`0.05 pF
`• The Electrode Parasitic capacitance is the capaci-
`tance presented by the touch sensor system for
`an electrode that is not being touched.
`• The Strong Electrode Touch capacitance is the
`change in capacitance from a touch directly over
`an electrode.
`• The Weak Electrode Touch capacitance is the
`change in capacitance from a touch next to an
`electrode. In other words, the effect on an elec-
`trode next to an electrode which has a touch over
`it.
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`Capacitance Measurement Methods
`There are a number of methods
`to measure
`capacitance. Some example methods are:
`• Relaxation Oscillator
`• Charge Time vs Voltage
`• Voltage Divider
`• Charge Transfer
`• Sigma-Delta Modulation
`
`CAPACITIVE SENSING MODULE
`(CSM)
`The CSM is a proprietary Microchip hardware module
`available in a variety of different PIC microcontrollers.
`The CSM enables the measurement of capacitance,
`based on the relaxation oscillator methodology.
`
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`
`The CSM produces an oscillating voltage signal for
`measurement, at a frequency dependent on the capac-
`itance of an object connected to the module. The basic
`concept is as follows:
`• CSM oscillates at some frequency, dependent on
`the capacitance of a connected sensing
`electrode.
`• CSM frequency changes when a touch is intro-
`duced near the sensing electrode because the
`touch changes the total capacitance presented by
`the electrode.
`• CSM frequency change is used as an indication of
`a touch condition.
`A simplified block diagram of the CSM to sensor
`interface is shown in Figure 5.
`
`FIGURE 5:
`
`CSM TO SENSOR INTERFACE BLOCK DIAGRAM
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`An example of the CSM measurement waveform is
`shown in Figure 6. It is a triangle wave because the
`CSM drives with a constant current source/sink.
`
`FIGURE 6:
`
`CSM WAVEFORM
`
`Measuring self capacitance does not easily lend itself
`to supporting multi-touch events, which requires
`correlation of multiple X and Y touched electrodes into
`multiple (X,Y) touch coordinates.
`
`Self Capacitance Measurement Method
`1. Connect a desired electrode for measurement
`to the CSM.
`2. Ground all other sensor electrodes.
`3. Measure the time duration required for a defined
`number of CSM cycles to occur.
`a) Chip timer TMR0 is used to count the
`desired number of CSM cycles.
`b) Chip timer TMR1 is used to measure the
`time duration for the desired number of
`CSM cycles to occur.
`4. Repeat steps 1-3 until all sensor electrodes
`have been measured.
`5. Subtract the measured value for each electrode
`from a previously acquired “no-touch” baseline
`value for the respective electrode.
`6. Compare the measured electrode change from
`baseline against a defined touch threshold
`value.
`
`Self Capacitance Example CSM
`Waveforms
`Example CSM waveforms for no-touch and touch
`conditions are shown in Figure 8.
`
`The CSM hardware can be user configured for the
`oscillating trip point voltage levels and the charge/
`discharge current.
`Trip Point Voltage Adjustment – Changing the CSM’s
`high and low trip point voltages will alter both the CSM
`waveform’s frequency and amplitude. Expanding the
`trip points to increase the waveform amplitude can
`improve the Signal to Noise Ratio (SNR). The flexibility
`to change the trip voltages enables optimization for
`different applications.
`Charge/Discharge Current Adjustment – Changing
`the CSM’s constant current charge/discharge value will
`alter the CSM waveform’s frequency.
`Higher current settings can improve the SNR. The
`flexibility to change the value of the constant current
`source/sink enables optimization
`for different
`applications.
`
`SELF CAPACITANCE
`Self capacitance is defined as the capacitive load, rela-
`tive to circuit ground, that an electrode presents to the
`measurement system (refer to Figure 7).
`FIGURE 7:
`SELF CAPACITANCE
`
`The self capacitance of each X and Y axis electrode on
`a sensor can be independently measured.
`Measuring the self capacitance of each individual sen-
`sor electrode provides for the determination of the
`(X,Y) location of a single touch event in progress.
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`FIGURE 8:
`
`SELF CAPACITANCE EXAMPLE CSM WAVEFORMS
`
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`Self Capacitance Example Measurement
`Values
`The measured self capacitance values are dependent
`on many variables, such as: sensor, integration of the
`sensor and controller configuration. Self capacitance
`example values are shown in Table 2.
`TABLE 2:
`SELF CAPACITANCE EXAMPLE VALUES
`
`Sensor Layer
`
`CSM Cycles
`Counted
`
`Scan Time per
`Electrode
`
`Top
`Bottom
`
`48
`89
`
`400 us
`400 us
`
`Measured Timer TMR1 Counts
`No-Touch
`Touch
`4400
`4600
`11000
`11200
`
`Delta
`200
`200
`
`MUTUAL CAPACITANCE
`Mutual capacitance is the capacitive coupling between
`objects. One example is the mutual capacitive coupling
`between an X and Y axis electrode on a projected
`capacitive touch sensor.
`The mutual capacitance measurement can be imple-
`mented with the electrodes on one sensor layer serving
`as receivers and the electrodes on the opposing sensor
`layer serving as transmitters.
`The capacitance relationships are shown in Figure 9
`for a single transmitter electrode and a single receiver
`electrode on the two opposing sensor layers.
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`FIGURE 9:
`
`MUTUAL CAPACITANCE
`
`A node is defined as the intersection of any single top
`sensor layer electrode with any single bottom layer
`electrode. A fully functional multi-touch system can be
`developed by taking mutual capacitance measure-
`ments at each node of the sensor. However, the time
`required to measure the entire sensor can be dramati-
`cally improved by only performing mutual capacitance
`measurement on dynamically selected nodes. See the
`“Self and Mutual Capacitance Measurements Com-
`bined” section for an explanation.
`Note: Measurements based on mutual capaci-
`tance enable position tracking of multiple
`simultaneous touch events occurring on a
`projected capacitive touch sensor. This is
`accomplished by performing mutual
`capacitance measurements at receiver/
`transmitter nodes (intersections) in order
`to correlate touched X and Y axis
`electrodes into (X,Y) coordinate pairs.
`
`Overview of How Mutual Capacitive
`Works
`A receiver electrode on the sensor’s bottom layer is
`connected to the CSM, which will oscillate at some fre-
`quency based on the capacitance of the connected
`electrode.
`A transmitter electrode on the sensor's top layer is
`driven with voltage pulses, synchronized to the CSM’s
`frequency.
`The transmitter pulses inject current into the receiver
`electrode's capacitance, through the mutual capaci-
`tance between the transmitter and receiver electrodes.
`The CSM's frequency slows down because the
`synchronized pulse current is injected into the receiver
`electrode's capacitance when the CSM is trying to
`discharge it.
`A finger touch near the node (intersection) of the
`receiver and transmitter electrodes provides a capaci-
`tively coupled ground path, which shunts away some of
`the transmitter pulse injected current.
`The CSM’s frequency speeds up because the finger
`touch steals some of the pulse injected current from the
`receiver electrode.
`The change in CSM frequency is used as an indication
`of the touch condition.
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`Mutual Capacitance Measurement
`top layer and drive it with a voltage pulse, each
`time the CSM waveform changes state from
`Method
`charging to discharging. The pulse injects cur-
`1. Select a receiver electrode on the sensor's bot-
`rent into the receiver electrode's capacitive load.
`tom layer for measurement and connect it to the
`This slows down the CSM frequency because
`CSM. The CSM will oscillate at some frequency,
`the pulse is synchronized to when the CSM is
`based on capacitance of the connected receiver
`discharging the capacitive load of the receiver
`electrode.
`electrode.
`2. Select a transmitter electrode on the sensor's
`3. Ground all other sensor electrodes.
`FIGURE 10:
`TRANSMITTER PULSE SYNCHRONIZATION
`
`4. Measure the time duration for a defined number
`of CSM cycles to occur for the selected receiver
`electrode.
`5. A finger touch near the node (intersection) of the
`selected receiver and transmitter electrodes
`
`provides a capacitively coupled “touch” shunting
`path for some of the pulse injected current. The
`shunting path steals some of the pulse injected
`current, which causes an increase in the CSM
`frequency.
`
`FIGURE 11:
`
`CSM AND MUTUAL CAPACITANCE METHOD
`
`6. Repeat steps 2-5 until each top layer electrode
`has served as a transmitter for a given receiver
`electrode.
`7. Repeat steps 1-6 until each bottom layer
`electrode has served as a receiver electrode.
`
`8. Subtract the measured value for each node
`(receiver and transmitter electrode intersection)
`from a previously acquired “no-touch” baseline
`value for the corresponding node.
`9. Compare the measured node change from
`baseline against a defined touch threshold
`value.
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`Mutual Capacitance Example CSM
`Waveforms
`Example CSM waveforms no-touch and
`conditions are shown in Figure 12.
`
`touch
`
`FIGURE 12:
`
`MUTUAL CAPACITANCE EXAMPLE CSM WAVEFORMS
`
`Note that the CSM frequency increases when a touch
`occurs at the selected node and decreases when the
`
`touch is away from the selected node.
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`Mutual Capacitance Example
`Measurement Values
`The measured mutual capacitance values are
`dependent on many variables, such as: sensor, inte-
`gration of the sensor and controller configuration.
`Mutual capacitance example values are shown in
`Table 3.
`TABLE 3:
`
`MUTUAL CAPACITANCE EXAMPLE VALUES
`Measured Timer TMR1 Counts
`Touch
`10850
`
`CSM Cycles
`Counted
`
`14
`
`Scan Time per Node
`
`1 ms
`
`No-Touch
`11000
`
`Delta
`150
`
`SELF AND MUTUAL CAPACITANCE
`MEASUREMENTS COMBINED
`Performing self capacitance measurements on all X
`and Y axis electrodes provides a fast system response
`time, but it does not easily support multi-touch tracking
`of multiple simultaneous touch events.
`Performing mutual capacitance measurements on all X
`and Y axis electrode nodes (intersections) supports
`tracking the (X,Y) coordinates of simultaneous multi-
`touch events, but the system response time is
`degraded when compared to the self capacitance
`method.
`A unique utilization of both self and mutual capacitance
`methods provides multi-touch capability with improved
`systems response time.
`
`Self on All Electrodes with Mutual to
`Correlate Touched Electrodes Method
`1. Perform self capacitance measurements on all
`sensor electrodes.
`2. Determine which X and Y axis electrodes are
`experiencing a touch event.
`3. Perform mutual (transmitter/receiver) capaci-
`tance measurements on only the X and Y elec-
`trodes identified as being touched from the self
`capacitance measurements.
`4. Correlated touched X and Y axis electrodes into
`one or more (X,Y) touch coordinates.
`
`Dual Touch Example
`Figure 13 is an example sensor with a simulated dual-
`touch condition. The location of two touches are
`represented as green dots.
`
`FIGURE 13:
`
`DUAL TOUCH EXAMPLE – FULL MAP
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`1. Measure the self capacitance of each individual
`sensor electrode.
`a) Self capacitance on X01
`b)
`:
`c) Self capacitance on X12
`d) Self capacitance on Y01
`e)
`:
`f)
`Self capacitance on Y09
`2. Compare each of the 12 X electrode self capac-
`itance delta measurement to a touch threshold
`value.
`a)
`Identify the touched X electrodes as X02
`and X05
`
`3. Compare each of the 9 Y electrode self capaci-
`tance delta measurement to a touch threshold
`value.
`a)
`Identify the touched Y electrodes as Y03
`and Y07
`
`FIGURE 14:
`
`DUAL TOUCH EXAMPLE – ELECTRODE IDENTIFICATION
`
`5.
`
`d) Mutual measurement 4: Pulse drive trans-
`mitter Y03 and measure capacitance of
`receiver X05.
`Identify two peaks from the four mutual mea-
`surements, in order to correlate the four touched
`electrodes (X02, X05, Y03, and Y07) into two
`unique (X,Y) touch locations
`
`4. Measure the mutual transmitter/receiver capac-
`itance on a subset of the sensor's node set, con-
`sisting of the intersections of electrodes X02,
`X05, Y03, and Y07.
`a) Mutual measurement 1: Pulse drive trans-
`mitter Y07 and measure capacitance of
`receiver X02.
`b) Mutual measurement 2: Pulse drive trans-
`mitter Y07 and measure capacitance of
`receiver X05.
`c) Mutual measurement 3: Pulse drive trans-
`mitter Y03 and measure capacitance of
`receiver X02.
`TABLE 4:
`DUAL TOUCH MUTUAL MEASUREMENTS EXAMPLE
`Mutual
`Measurement
`20
`130
`110
`15
`
`X02
`X05
`X02
`X05
`
`Y07
`Y07
`Y03
`Y03
`
`Receiver
`
`Transmitter
`
`Peak Mutual
`
`Touches
`
`(X05, Y07)
`(X02, Y03)
`
`X
`X
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`The touch coordinates for the dual touches have been
`determined as shown below.
`
`FIGURE 15:
`
`DUAL TOUCH EXAMPLE – X AND Y ELECTRODE CORRELATION
`
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`FIGURE 16:
`
`BASELINE LOGIC
`
`BASELINE
`Due to parasitic capacitance variations in the touch
`system
`that can not be controlled, a
`touch
`is
`determined based on measurement differences from
`“no-touch” capacitance measurements. The “no-touch”
`reference values are referred to as the baseline.
`The concept is to normalize raw measured touch
`values using the baseline no-touch values as follows.
`Normalized = Raw – Baseline
`Note:
`The baseline reference method is critically
`important to system operation! It provides
`“relative”, as opposed to “absolute” touch
`measurement values.
`
`The baseline image contains a measured self capaci-
`tance value for every sensor electrode and a measured
`mutual capacitance value for every sensor node.
`A new baseline image of the sensor's “no-touch”
`capacitance is taken approximately every 800 ms,
`when there is no touch activity.
`A “no-touch” condition is checked to exist at the begin-
`ning and end of measuring a new baseline, before it is
`accepted for use.
`The baseline taking logic is shown in Figure 16.
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`For example, a sensor layer with 9 electrodes would
`have a total resolution of:
`128*(9 electrodes – 1) = 1024 points
`The center of each electrode has a value that
`corresponds to incrementing multiples of the 128 point
`electrode resolution.
`
`FIGURE 17:
`
`LAYER RESOLUTION MAP
`EXAMPLE
`
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`RESOLUTION
`Resolution is defined as the smallest change in the
`touch location, which can be discriminated. It is the
`smallest measurable step size of the system.
`The coarse resolution of a projected capacitive sensor
`is
`the physical distance between electrodes,
`sometimes called the pitch spacing. For example, if the
`electrodes are spaced 5 mm apart on the sensor, then
`the course touch resolution is 5 mm.
`The coarse electrode pitch on a given sensor usually
`does not provide the desired level of touch system res-
`olution. The touch resolution can be greatly improved
`from the course sensor's electrode pitch by more finely
`interpolating
`touch positions between adjacent
`electrodes.
`
`Interpolation Method
`The basic interpolating steps are as follows.
`1. Determine the course touch position by identify-
`ing the electrode with the peak measured signal.
`2. Determine the fine touch position by calculating
`a ratio of the measured signal strength for the
`two electrodes that are adjacent to the identified
`peak electrode.
`The design implementation is based on a set resolution
`between each pair of adjacent electrodes of 128 points.
`The overall resolution for a sensor layer will be this
`electrode resolution of 128 times one less than the
`number of electrodes making up the layer.
`
`InterpolatedPosition
`
`=
`
`Electrode n Position
`
`+
`
`ElectrodePitch
`
`------------------------------------------
`
`2
`
`
`
`
`
`
`Amplitude Electrode n
`Electrode n
`Amplitude
`1–
`1+
`–
`
`---------------------------------------------------------------------------------------------------------------------------------------------------------
`Electrode n Amplitude
`
`
`
`
`
`The interpolation is calculated as follows:
`
`FIGURE 18:
`
`INTERPOLATING TOUCH POSITION
`
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`EXAMPLE ELECTRODE INTERPOLATION
`CALCULATION
`An example interpolation calculation is shown in
`Figure 19 for a condition in which electrode Y04 has
`been identified as having the peak measured amplitude
`for the Y-axis layer.
`
`Conceptually, the resolution can be adjusted by chang-
`ing the set 128 electrode resolution to some other
`value. Increasing the electrode resolution will likely
`require lengthening of the capacitance measurement
`durations in order to increase the measured signal. The
`trade off is that higher resolution will slow the speed at
`which the sensor can be measured and therefore
`decrease the touch responsiveness of the system.
`TABLE 5:
`ELECTRODE INTERPOLATION CALCULATION EXAMPLE VALUES
`ID
`Position
`Measured Value
`Peak or Adjacent
`Y03
`256
`25
`Adjacent to peak
`Y04
`384
`100
`Peak
`Y05
`512
`75
`Adjacent to Peak
`Interpolated Position:
`= Electrode(n)Position + (ElectrodePitch/2)•(Electrode(n + 1)Amp – Electrode(n – 1)Amp)/Electrode(n)Amp
`= 384 + (128/2)•(75-25)/100
`= 416
`
`Formula ID
`Electrode(n – 1)
`Electrode(n)
`Electrode(n + 1)
`
`FIGURE 19:
`
`ELECTRODE INTERPOLATION CALCULATION EXAMPLE MAP
`
`FILTERING
`Many different software filtering algorithms can be
`implemented to enhance the quality of reported touch
`positions. Software filtering, however, can sometimes
`be a trade off with the controller's code space, RAM
`space, and the time required to resolve touch events on
`the sensor.
`
`Sampling Filter
`A sampling filter collects a number of capacitance mea-
`surement samples, then calculates the average value
`of the sample set. This can be an effective filter, but
`many applications may not need it to be implemented.
`
`Integration Filtering
`An integration filter is achieved by adjusting the length
`of time the capacitance is measured. This is done by
`increasing the number of CSM cycles that are counted
`for the time-based measurement.
`Increasing the number of CSM cycles that are counted
`increases the level of the integration filtering, but it
`comes at the expense of taking more time to perform
`the measurements.
`
`Touch Detection Filter
`A touch detection filter compares a measurement sam-
`ple to a defined touch threshold value. The measured
`sample is only accepted if it passes the test against the
`threshold value.
`
` 2010 Microchip Technology Inc.
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`Coordinate Filtering
`A coordinate filter collects a number of sequential
`reported
`touch coordinates and averages
`them
`together into the next coordinate to be reported. It is a
`FIFO (First In, First Out) or “ring buffer” type of filter,
`applied to touch coordinates.
`A good balance of responsiveness and smoothing can
`be achieved by performing a rolling average of
`approximately 4 coordinate values.
`
`Touch coordinates are sent from the controller to the
`host system in a 5-byte data packet. The packet
`contains: multi-Touch ID #, Pen-Up/Down touch status,
`X-axis coordinate, and Y-axis coordinate.
`The touch coordinate report data packet is shown in
`Table 6.
`
`Bit 2
`P2
`X2
`X9
`Y2
`Y9
`
`Bit 1
`P1
`X1
`X8
`Y1
`Y8
`
`Bit 0
`P0
`X0
`X7
`Y0
`Y7
`
`TOUCH REPORTING PROTOCOL
`TABLE 6:
`TOUCH COORDINATE REPORTING PROTOCOL
`Byte No.
`Bit 7
`Bit 6
`Bit 5
`Bit 4
`Bit 3
`1
`T1
`T0
`0
`0
`1
`0
`X6
`X5
`X4
`X3
`2
`0
`0
`0
`0
`0
`3
`0
`Y6
`Y5
`Y4
`Y3
`4
`0
`0
`0
`0
`0
`5
`NOTICE
`T<1:0>: Multi-Touch Point ID Number
`00 = Touch #0
`Microchip's mTouch family of processors supports
`01 = Touch #1
`advanced multi-touch gesture recognition. Certain
`gesture recognition implementations and/or gesture/
`P<2:0>: Pen/Touch Status
`function combinations may be subject to patent rights
`000 = Pen-up
`not owned or licensed by Microchip, and thus unavail-
`001 = Pen-Down
`able for use without proper licensing. Microchip makes
`no representations, extends no warranties of any kind,
`X<9:0>: X-axis Coordinate Value
`either express or implied, and assumes no responsibil-
`0000000000 = 0
`ities whatever with respect to the manufacture, use,
`sale, or other disposition by Licensee of products made
`or methods employed under this License Agreement.
`Licensee is responsible for conducting its own due dili-
`gence concerning third party intellectual property
`rights, and to obtain licenses from third parties where
`necessary.
`
`:1
`
`111111111 = 1023
`Y<9:0>: Y-axis Coordinate Value
`0000000000 = 0
`
`:1
`
`111111111 = 1023
`
`DS93064A-page 14
`
` 2010 Microchip Technology Inc.
`
`DELL EXHIBIT 1017 PAGE 14
`
`DELL EXHIBIT 1017 PAGE 14
`
`

`

`Note the following details of the code protection feature on Microchip devices:
`•
`Microchip products meet the specification contained in their particular Microchip Data Sheet.
`
`•
`
`•
`
`•
`
`•
`
`Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
`intended manner and under normal conditions.
`
`There are dishonest and poss bly illegal methods used to breach the code protection feature. All of these methods, to our
`knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
`Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
`
`Microchip is willing to work with the customer who is concerned about the integrity of their code.
`
`Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
`mean that we are guaranteeing the product as “unbreakable.”
`
`Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
`products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
`allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
`
`Information contained in this publication regarding device
`applications and the l ke is provided only for your convenience
`and may be superseded by updates. It is your responsibility to
`ensure that your application meets with your specifications.
`MICROCHIP MAKES NO REPRESENTATIONS OR
`WARRANTIES OF ANY KIND WHETHER EXPRESS OR
`IMPLIED, WRITTEN OR ORAL, STATUTORY OR
`OTHERWISE, RELATED TO THE
`INFORMATION,
`INCLUDING BUT NOT LIMITED TO ITS CONDITION,
`QUALITY, PERFORMANCE, MERCHANTABILITY OR
`FITNESS FOR PURPOSE. Microchip disclaims all liability
`arising from this information and its use. Use of Microchip
`devices in life support and/or safety applications is entirely at
`the buyer’s risk, and the buyer agrees to defend, indemnify and
`hold harmless Microchip from any and all damages, claims,
`suits, or expenses resulting from such use. No licenses are
`conveyed,
`implicitly or otherwise, under any Microchip
`intellectual property rights.
`
`Trademarks
`The Microchip name and logo, the Microchip logo, dsPIC,
`KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,
`PIC32 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, 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, Octopus, 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.
`© 2010, Microchip Technology Incorporated, Printed in the
`U.S.A., All Rights Reserved.
` Printed on recycled paper.
`
`ISBN: 978-1-60932-466-7
`
`Microchip received ISO/TS-16949:2002 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® MCUs and dsPIC® DSCs, KEELOQ® code hopping
`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.
`
` 2010 Microchip Technology Inc.
`
`DS93064A-page 15
`
`DELL EXHIBIT 1017 PAGE 15
`
`DELL EXHIBIT 1017 PAGE 15
`
`

`

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`
`DS93064A-page 16
`
` 2010 Microchip Technology Inc.
`
`01/05/10
`
`DELL EXHIBIT 1017 PAGE 16
`
`DELL EXHIBIT 1017 PAGE 16
`
`