Datasheet QT60161B-AS Datasheet (QPROX)

LQ QT60161B

16 KEY QMatrix™ K

 Advanced second generation QMatrix controller  16 touch keys through any dielectric  100% autocal for life - no adjustments required  SPI Slave or Master/Slave interface to a host controller  Parallel scan interface for electromechanical compatibility  Keys individually adjustable for sensitivity, response time,

and many other critical parameters

 Sleep mode with wake pin  Synchronous noise suppression  Mix and match key sizes & shapes in one panel  Adjacent key suppression feature  Panel thicknesses to 5 cm or more  Low overhead communications protocol

MOSI

MISO

SCK

RST

Vdd

Vss

XTO

XTI

EYPANEL SENSOR

DRDY

VREF

43 42

11 23

41 40393837363435

QT60161B

TQFP-44

1615

14 22

SMP

X0OPA

X1OPBX2X3

CS0A

CS1A

CS0B

LED

Vdd

Vss

Vdd

Vss

CS1B

21192018

XS0

XS1

XS2

XS3

CS2A1

CS2B

CS3A

CS3B

Aref

AGnd

AVd d

YS3

YS2

YS1

YS0

 44-pin TQFP package

APPLICATIONS -

 Security keypanels



Industrial keyboards



Appliance controls



Outdoor keypads



ATM machines



Touch-screens

The QT60161B digital charge-transfer (“QT”) QMatrix™ IC is designed to detect human touch on up 16 keys when used in conjunction with a scanned, passive X-Y matrix. It will project the keys through almost any dielectric, e.g. glass, plastic, stone, ceramic, and even wood, up to thicknesses of 5 cm or more. The touch areas are defined as simple 2-part interdigitated electrodes of conductive material, like copper or screened silver or carbon deposited on the rear of a control panel. Key sizes, shapes and placement are almost entirely arbitrary; sizes and shapes of keys can be mixed within a single panel of keys and can vary by a factor of 20:1 in surface area. The sensitivity of each key can be set individually via simple functions over the SPI or UART port, for example via Quantum’s QmBtn program, or from a host microcontroller. Key setups are stored in an onboard eeprom and do not need to be reloaded with each powerup.

The device is designed specifically for appliances, electronic kiosks, security panels, portable instruments, machine tools, or similar products that are subject to environmental influences or even vandalism. It can permit the construction of 100% sealed, watertight control panels that are immune to humidity, temperature, dirt accumulation, or the physical deterioration of the panel surface from abrasion, chemicals, or abuse. To this end the device contains Quantum-pioneered adaptive auto self-calibration, drift compensation, and digital filtering algorithms that make the sensing function robust and survivable.

The part can scan matrix touch keys over LCD panels or other displays when used with clear ITO electrodes arranged in a matrix. It does not require 'chip on glass' or other exotic fabrication techniques, thus allowing the OEM to source the matrix from multiple vendors. Materials such as such common PCB materials or flex circuits can be used.

External circuitry consists of a resonator and a few capacitors and resistors, all of which can fit into a footprint of less than 6 sq. cm (1 sq. in). Control and data transfer is via either a SPI or UART port; a parallel scan port provides backwards compatibility with scanned electromechanical keys.

The QT60161B makes use of an important new variant of charge-transfer sensing, transverse charge-transfer, in a matrix format that minimizes the number of required scan lines. Unlike some older technologies it does not require one sensing IC per key.

The QT60161B is identical to earlier QT60161 in all respects except that the device exhibits lower signal noise. This device replaces QT60161 parts directly. After December 2003 the QT60161 will no longer be sold.



Automotive panels



Machine tools

AVAILABLE OPTIONS

TQFP Part NumberT

QT60161B-AS-400C to +1050C

Pat Pend. R1.03/04.03

Contents

1 Overview

2 Signal Processing

3 Circuit Operation

4 Communications Interfaces

5 Commands & Functions

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3.3.1 RFI From X Lines

3.3.2 Noise Coupling Into X lines

3.4.1 RFI From Y Lines

3.4.2 Noise Coupling Into Y Lines

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g 0x67 - Get Command

p 0x70 - Put Command

s 0x73 - Specific Key Scope

S 0x53 - All Keys Scope

x 0x78 - Row Keys Scope

y 0x79 - Column Keys Scope

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©Quantum Research Group Ltd.

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41.1 Field Flows

41.2 Circuit Overview

41.3 Communications 5

52.1 Negative Threshold

52.2 Positive Threshold

52.3 Hysteresis

52.4 Drift Compensation

62.5 Negative Recalibration Delay

62.6 Detection Integrator

62.7 Positive Recalibration Delay

62.8 Reference Guardbanding

62.9 Adjacent Key Suppression (‘AKS’)

72.10 Full Recalibration

72.11 Device Status & Reporting 7

73.1 Matrix Scan Sequence

73.2 Signal Path

83.3 'X' Electrode Drives 8 8

83.4 'Y' Gate Drives 8 8

83.5 Burst Length & Sensitivity

83.6 Burst Acquisition Duration

93.7 Intra-Burst Spacing

93.8 Burst Spacing

93.9 Sample Capacitors

93.10 Water Film Suppression

93.11 Reset Input

93.12 Oscillator

93.13 Startup / Calibration Times

93.14 Sleep_Wake / Noise Sync Pin (WS)

103.15 LED / Alert Output

113.16 Oscilloscope Sync

113.17 Power Supply & PCB Layout

113.18 ESD / Noise Considerations 11

114.1 Serial Protocol Overview

124.2 SPI Port Specifications

124.3 SPI Slave-Only Mode

134.4 SPI Master-Slave Mode

144.5 UART Interface

154.6 Sensor Echo and Data Response

154.7 Parallel Scan Port

164.8 Eeprom Corruption 17

175.1 Put / Get Direction Commands 17 17

185.2 Scope Commands 18 18 18 18

0 0x30 - Signal for Single Key

1 0x31 - Delta Signal for Single Key

2 0x32 - Reference Value

5 0x35 - Detection Integrator Counts

6 0x36 - Eeprom Checksum

7 0x37 - General Device Status

<sp> 0x20 - Signal Levels for Group

! 0x21 - Delta Signals for Group

" 0x22 - Reference Levels for Group

% 0x25 - Detect Integrator Counts for Group

e 0x65 - Error Code for Selected Key

E 0x45 - Error Codes for Group

k 0x6B - Reporting of First Touched Key

^A 0x01 - Negative Detect Threshold

^B 0x02 - Positive Detect Threshold

^C 0x03 - Negative Threshold Hysteresis

^D 0x04 - Positive Threshold Hysteresis

^F 0x06 - Burst Length

^G 0x07 - Burst Spacing

^H 0x08 - Negative Drift Compensation Rate5

^I 0x09 - Positive Drift Compensation Rate

^J 0x0A - Negative Detect Integrator Limit

^K 0x0B - Positive Recalibration Delay

^L 0x0C - Negative Recalibration Delay

^M 0x0D - Intra-Burst Pulse Spacing

^N 0x0E - Positive Reference Error Band

^O 0x0F - Negative Reference Error Band

^P 0x10 - Adjacent Key Suppression (‘AKS’)

6 0x36 - Eeprom Checksum

L 0x4C - Lock Reference Levels

b 0x62 - Recalibrate Keys

l 0x6C - Return Last Command Character

r 0x72 - Reset Device

V 0x56 - Return Part Version

W 0x57 - Return Part Signature

Z 0x5A - Enter Sleep

^Q 0x11 - Data Rate Selection

^R 0x12 - Oscilloscope Sync

^W 0x17 - Noise Sync

6 Electrical Specifications

7 Mechanical

8 Index

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185.3 Status Commands 18 18 18 18 18 19 19 19 19 19 19 20 20

215.4 Setup Commands 21 21 21 21 21 22 22 22 22 23 23 23 23 23 24

245.5 Supervisory / System Functions 24 24 24 25 25 25 25 25 25 26 26

275.6 Function Summary Table

305.7 Timing Limitations

305.8 Erratta / Notes 31

316.1 Absolute Maximum Specifications

316.2 Recommended operating conditions

316.3 DC Specifications

316.4 Protocol Timing

326.5 Maximum Drdy Response Delays 33

337.1 Dimensions

337.2 Marking 34

www.qprox.com QT60161B / R1.03

Table 1.1 Device Pin Lis

I/O PPMOSI1

I/O PPMISO2

I/O: I = Input

O = Output Pwr = Power pin I/O = Bidirectional line PP = Push Pull output drive OD = Open drain output drive

©Quantum Research Group Ltd.

DescriptionTypeNamePin

Master-Out / Slave In SPI line. In Master/Slave SPI mode is used for both communication directions. In Slave SPI mode is the data input (in only). Master-In / Slave Out SPI line. Not used in Master/Slave SPI mode. In Slave mode outputs data to host (out only). SPI Clock. In Master mode is an output; in Slave mode is an inputI/O PPSCK3 Reset input, active low resetIRST4 +5V supplyPwrVdd5 GroundPwrVss6 Oscillator drive output. Connect to resonator or crystal.plyO PPXTO7 Oscillator drive input. Connect to resonator or crystal, or external clock source.IXTI8 UART receive inputIRX9 UART transmit outputO PPTX10 Wake from Sleep / Sync to noise sourceIWS11 Sample output controlO PPSMP12 X0 Drive matrix scan / Communications option A inputI/O PPX0OPA13 X1 Drive matrix scan / Communications option B inputI/O PPX1OPB14 X2 Drive matrix scanO PPX215 X3 Drive matrix scanO PPX316 +5V supplyPwrVdd17 GroundPwrVss18 XS0 Scan input lineIXS019 XS1 Scan input lineIXS120 XS2 Scan input lineIXS221 XS3 Scan input lineIXS322 YS0 Scan output lineO PPYS023 YS1 Scan output lineO PPYS124 YS2 Scan output lineO PPYS225 YS3 Scan output lineO PPYS326 +5 supply for analog sectionsPwrAVdd27 Analog groundPwrAGnd28 +5 supply for analog sectionsPwrAref29 Cs3 control BI/O PPCS3B30 Cs3 control AI/O PPCS3A31 Cs2 control BI/O PPCS2B32 Cs2 control AI/O PPCS2A33 Cs1 control BI/O PPCS1B34 Cs1 control AI/O PPCS1A35 Cs0 control BI/O PPCS0B36 Cs0 control AI/O PPCS0A37 +5 supplyPwrVdd38 GroundPwrVss39 Active low LED status drive / Activity indicatorO PPLED40 Data ready output for Slave SPI mode; active lowO ODDRDY41 Vref input for conversion referenceIVref42 Oscilloscope sync outputO PPSO43 Slave select for SPI direction control; active lowI/O ODSS44

iii

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©Quantum Research Group Ltd.

1 Overview

QMatrix devices are digital burst mode charge-transfer (QT) sensors designed specifically for matrix geometry touch controls; they include all signal processing functions necessary to provide stable sensing under a wide variety of changing conditions. Only a few low cost external parts are required for operation. The entire circuit can be built in under 6 square centimeters of PCB area.

Figure 1-1 Field flow between X and Y elements

overlying panel

element

The device has a wide dynamic range that allows for a wide variety of key sizes and shapes to be mixed together in a single touch panel. These features permit new types of keypad features such as touch-sliders, back-illuminated keys, and complex warped panels.

The devices use an SPI interface running at up to 3MHz rates to allow key data to be extracted and to permit individual key parameter setup, or, a UART port which can run at rates to

57.6 Kbaud. The serial interface protocol uses simple commands; the command structure is designed to minimize the amount of data traffic while maximizing the amount of information conveyed.

In addition to normal operating and setup functions the device can also report back actual signal strengths and error codes over the serial interfaces.

QmBtn software for the PC can be used to program the IC as well as read back key status and signal levels in real time.

A parallel scan port is also provided that can be used to directly replace membrane type keypads.

QMatrix technology employs transverse charge-transfer ('QT') sensing, a new technology that senses the changes in an electrical charge forced across an electrode set.

Figure 1-3 Fields With a Conductive Film

1.1 Field Flows

Figure 1-1 shows how charge is transferred across an electrode set to permeate the overlying panel material; this charge flow exhibits a high dQ/dt during the edge transitions of the X drive pulse. The

elem ent

Figure 1-2 Field Flows When Touched

element

Figure 1-4 Sample Electrode Geometries

PARALLEL LINES SERPENTINE SPIRAL

charge driven by the X electrode is partly received onto the corresponding Y electrode which is then processed. The part uses 4 'X' edge-driven rows and 4 'Y' sense columns to sense up to 16 keys.

The charge flows are absorbed by the touch of a human finger (Figure 1-1) resulting in a decrease in coupling from X to Y. Thus, received signals decrease or go negative with respect to the reference level during a touch.

As shown in Figure 1-3, water films cause the coupled fields to increase slightly, making them easy to distinguish from touch.

1.2 Circuit Overview

A basic circuit diagram is shown in Figure 1-5. The ‘X’ drives are sequentially pulsed in groupings of bursts. At the intersection of each ‘X’ and ‘Y’ line in the matrix itself, where a key is desired, should be an interdigitated electrode set similar to those shown in Figure 1-4. See Quantum App Note AN-KD01, or consult Quantum for application assistance.

The device uses fixed external capacitors to acquire charge from the matrix during a burst of charge-transfer cycles; the burst length can be varied to permit digitally variable key signal gains. The charge is converted to digital using a

single-slope conversion process.

Burst mode operation permits the use of a passive matrix, reduces RF emissions, and provides excellent response times.

Refer to Section 3 for more details on circuit operation.

1.3 Communications

The device uses two variants of SPI

overlying panel

element

communications, Slave-only and Master-Slave, a UART interface, plus a parallel scan interface. Over the serial interfaces are used a command and data transfer structure designed for high levels of flexibility using minimal numbers of bytes. For more information see Sections 4 and 5.

The parallel scan port permits the replacement of electromechanical keypads that would be scanned by a microcontroller; the scan interface mimics an electromechanical keyboard’s response.

www.qprox.com QT60161B / R1.03

©Quantum Research Group Ltd.

Figure 1-5 Circuit Block Diagram

Opt B

Opt A

QT60161

LED

Scope Sync

Reset

Wake / Sync

CS0A

CS0B

SPI to Host

CS1A

UART

CS1B

to Host

CS2A

CS2B

CS3A

CS3B

Scan Output

VREF

Scan Input

Sample

Sample caps

CS0

CS1

CS2

CS3

Y0 Y1 Y2 Y3

2 Signal Processing

The device calibrates and processes signals using a number of algorithms specifically designed to provide for high survivability in the face of adverse environmental challenges. The QT60161B provides a large number of processing options which can be user-selected to implement very flexible, robust keypanel solutions.

2.1 Negative Threshold

See also Command ^R, page 26

The ‘SO’ pin can output an oscilloscope sync signal which is a positive pulse that brackets the burst of a selected key. This feature is controlled by the ^R command. More than one burst can output a sync pulse, for example if the scope of the command when set is a row or column, or is all keys. The ^R command is volatile and does not survive a reset or power down.

This feature is invaluable for diagnostics; without it, observing signals clearly on an oscilloscope for a particular burst is nearly impossible.

This function is supported in QmBtn PC software via a checkbox.

3.17 Power Supply & PCB Layout

Vdd should be 5.0 volts +/- 5%. This can be provided by a common 78L05 3-terminal regulator. LDO type regulators are often fine but can suffer from poor transient load response which may cause erratic signal behavior.

If the power supply is shared with another electronic system, care should be taken to assure that the supply is free of low-level spikes, sags, and surges which can adversely affect the circuit. The devices can track slow changes in Vcc depending on the settings of drift compensation, but signals can be adversely affected by rapid voltage steps and impulse noise on the supply rail.

Supply bypass capacitors of 0.1uF to a ground plane should be used near every supply pin of every active component in the circuit.

PCB layout: The PCB layout should incorporate a ground plane under the entire circuit; this is easily possible with a 2-layer design. The ground plane should be broken up as little as possible. Internal nodes of the circuit can be quite sensitive to external noise and the circuit should be kept away from stray magnetic and electric fields, for example those emanating from mains power components such as transformers and power capacitors. If proximity to such components is unavoidable, an electrostatic shield may be required.

The use of the Sync feature (Section 3.14) can be invaluable in reducing these types of noise sources, but only up to a point.

3.18 ESD / Noise Considerations

In general the QT60161B will be well protected from static discharge during use by the overlying panel. However, even with a dielectric panel transients currents can still flow into scan lines via induction or in extreme cases, dielectric breakdown. Porous or cracked materials may allow a spark to tunnel through the panel. In all cases, testing is required to reveal any potential problems. The IC has diode protected pins which can absorb and protect the device from most induced discharges, up to 5mA.

The X lines are not usually at risk during operation, since they are low-resistance output drives. Diode clamps can be used on the X and Y matrix lines if desired. The diodes should be high speed / high current types such as BAV99 dual diodes, connected from Vdd to Vss with the diode junction connected to the matrix pin. Diode arrays can also be used.

Capacitors placed on the X and Y matrix lines can also help to a limited degree by absorbing ESD transients and lowering induced voltages. Values up to 100pF on the X lines and 22pF on the Y lines can be used.

The circuit can be further protected by inserting series resistors into the X and/or Y lines to limit peak transient current. RC networks as shown in Figures 4-6 and 4-7 can provide enhanced protection against ESD while also limiting the effects of external EMI should this be a problem.

External field interference can occur in some cases; these problems are highly dependent on the interfering frequency and the manner of coupling into the circuit. PCB layout (Section 3.17) and external wiring should be carefully designed to reduce the probability of these effects occurring.

SPI / UART data noise: In some applications it is necessary to have the host MCU at a distance from the sensor, perhaps with the interface coupled via ribbon cable. The SPI link is particularly vulnerable to noise injection on these lines; corrupted or false commands can be induced from transients on the power supply or ground wiring. Bypass capacitors and series resistors can be used to prevent these effects as shown in Figures 4-6 and 4-7.

4 Communications Interfaces

The QT60161B uses parallel, UART, and SPI interfaces to communicate with a host MCU. The serial interfaces use a protocol described in Section 5. Only one interface can be used at a time; the interface type is selected by resistor-coupled jumpers connected to pins X0OPA (pin 13) and X0OPB (pin 14) shown in Table 4-1. See also Figure 3-2.

Further specific information on each interface type is contained in the following sections:

SPI Slave-Only Mode: Section 4.3 SPI Master-Slave Mode: Section 4.4 UART Interface: Section 4.5 Parallel Interface: Section 4.7

4.1 Serial Protocol Overview

The SPI and UART interface protocols are based entirely on polled data transmission, that is, the part will not send data to the host of its own volition but will do so only in response to specific commands from a host.

www.qprox.com QT60161B / R1.03

©Quantum Research Group Ltd.

Run-time data responses, such as key detection or error information, requires simple single-byte functions to evoke a response from the part.

Setup mode interactions mostly use 2-byte functions from the host to cause the part to alter its behavior; these functions also cause writes to the internal eeprom.

The concept of 'scope' is used to allow functions to operate on individual keys or groupings of keys. The scope of subsequent functions can be altered by short initial scope instructions.

See Section 5 for protocol details.

4.2 SPI Port Specifications

The part has an SPI synchronous serial interface with the following specifications at 12MHz oscillator frequency:

Max clock rate, Fck 3MHz Data length 8 bits Host command space, Tcm m 50µs Response delay to host, Tdr1 Table 4-1, also, Sec. 6 Drdy delay from response, Tdr2 1µs to 1ms Multi-byte return spacing, Tdr3 10µs to 2ms

The host can clock the SPI with the part in Slave mode at any rate up to and including the maximum clock rate Fck. The maximum clock rate of the part in Master mode is determined by Setup ^Q (page 25).

The part can operate in either master-slave mode or slave-only mode, and is thus compatible with virtually all SPI-capable microcontrollers.

The SPI interface should not be used over long distances due to problems with signal ringing and introduced noise etc. unless suitably buffered or filtered with RC networks as shown in Figures 4-6 and 4-7. Slower data rates with longer RC timeconstants will provide enhanced resistance to noise and ringing problems.

4.3 SPI Slave-Only Mode

Refer to Figures 4-1, 4-3 and 4-2. In Slave-only mode the host must always be in Master mode, as it controls all SPI activity including the clocking of the interface in both directions. Unlike hardware SPI slaves, the QT60161B needs processing time to respond to functions. DRDY’ is used to let the host know when data is ready for collection; it indicates to the host when data is ready in response to a command so that the host can clock over the data.

This mode requires 5 signals to operate:

MOSI - Master out / Slave in data pin; used as an input for

data from connected to the MOSI pin of the host device.

MISO - Master in / Slave out data pin; used as an output for

data to to the MISO pin of the host device.

SCK - SPI clock - input only clock pin from host. The host

must shift out data on the falling edge of SCK; the QT60161B clocks data in on the rising edge of SCK. Important note: SCK must idle low just before and after SS’ transitions either up or down, or the transmission will fail; between bytes SCK should idle low.

SS’ - Slave select - input only; this pin acts as a framing

signal to the sensor from the host. This line must go low

the host at all times. This pin should be

the host at all times. This pin should be connected

just before and during reception of data from the host. It must not go high again until the SCK line has returned low; during data or echo response it must not go high until after the host has sensed that DRDY’ has gone high from the device. This pin must idle high. The SS’ pin has an internal pullup resistor inside.

DRDY’ - Data Ready - active-low - indicates to the host that

the part is ready to send data back subsequent to a command from the host. This pin idles high. The DRDY’ pin has an internal pullup resistor inside.

Internal pullup resistors note: The internal pullup resistors can range from 35k to 120k ohms. If RC filtering is used on the SPI lines per Figure 4-6, this resistance may not be low enough to ensure adequate signal risetime and may need to be augmented with external 10k pullups.

The host must wait until DRDY’ goes low before an SPI transfer to retrieve data. For multi-byte responses, the host must observe DRDY' to see when it goes high again after each data byte, then low again, before executing another transfer to get the next data byte. The host should send null bytes (0x00) to retrieve data.

If the DRDY’ line does not go low after a command, the command was not properly received or it was inappropriate. The delay to DRDY’ low depends on the command and how many bytes of data are being stored into eeprom; Table 4-1 shows the maximum delays encountered in most cases. Absolute worst case delays are found in Section 6-5; these timings occur only rarely, for example if the device happens to be busy with adjacent key suppression calculations, which occurs only at the moment when a key is first detected.

A typical Slave-only function sequence is as follows:

1) The host pulls SS’ low, then transfers a command to the sensor. The host then releases SS’ to float high. DRDY’ is unaffected in this step.

2) For 2-byte functions, (1) is repeated with a m50us delay.

3) When the sensor has the command echo or requested data ready to send back to the host, it loads it into its SPI register and pulls DRDY’ low.

4) The host detects that the sensor has pulled DRDY’ low and in turn the host pulls SS’ low.

5) The host obtains the byte from the sensor by transmitting a dummy byte (0x00) to the sensor.

6) The sensor releases DRDY’ to float high.

7) After the host detects that DRDY' has floated high the host must allow SS’ to also float high.

8) For multi-byte responses, steps (3) through (7) are repeated until the return data is completely sent.

Note that the host must release the SS’ line in step (7) even between multiple byte responses because the QT60161B waits for the SS’ line to return high before signalling that the next byte is ready for collection.

Note also that the host should check the DRDY’ line and wait for it to go high before transmitting another byte. Until the DRDY’ line is released the sensor is still processing a data return, even if the complete response data has been fully transferred; the sensor may still be busy when the host finishes the byte transfer and may not be able to digest a new command immediately.

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©Quantum Research Group Ltd.

See Section 3.15, page 10, for a description of the Alert pin which can be used to reduce communication traffic.

4.4 SPI Master-Slave Mode

Refer to Figures 4-1, 4-2, and 4-4. In Master-Slave mode the host and the sensor take turns being Master, with the host always leading off in Master mode during an exchange. The current Master always controls all 3 signal lines. The sensor takes a variable amount of time to respond to the host, depending on the nature of the function and its current and pending tasks. The host, like the sensor, must idle in slave mode when not sending a command.

Master/Slave requires 3 signals to operate:

MOSI - Master out / Slave in data pin - bidirectional - an input

pin while the host is transmitting data; an output when the sensor is transmitting data. The MOSI of the host and slave should be tied together. The MISO lines are not used on either part and should be left open.

SCK - SPI clock - bidirectional - an input pin when receiving

data; an output pin when sending. The host must shift out data on the falling edge of SCK; the QT60161B clocks data in on the rising edge of SCK. Important note: SCK from the host must be low before asserting SS’ low or high at either end of a byte or the transmission will fail. SCK should idle low; if in doubt, a 10K pulldown resistor should be used. When the sensor returns data it becomes the Master; data is shifted out by it on the falling edge of SCK and should be clocked in by the host on the rising edge.

SS’ - Slave select - bidirectional framing control. When the

sensor is in slave mode, this pin accepts the SS’ control signal from the host. In either data direction, SS' must go low before and any during data transfer; it should not go high again until SCK has returned low at the end of a byte. In Master mode the sensor asserts control over this line, to make the host a slave and to frame the data. This line must idle high; the part includes an internal pullup resistor and should be floated during idle times.

Internal pullup resistor note: The internal pullup resistor on SS’ can range from 35k to 120k ohms. If RC filtering is used on the SPI lines per Figure 4-7, this pullup resistance may not be low enough to ensure adequate signal risetime and may need to be augmented with external 10k pullups.

A command may consist of one or two bytes with a m50us delay between command bytes. At the end of a full command, the Master must go into Slave mode to await a response from the sensor.

The sensor may take some time to process the host command and respond. When it does so, it asserts SS’ low and begins clocking its data. For multi-byte responses, the bytes will be sent at intervals which may be somewhat irregular depending on the request and the processing load of the sensor. The host must be prepared to accept the sensor data as it comes or there can be a data overrun in the host. If the data returns too fast for the host

to accept it, the SPI clock rate should be lowered.

A typical Master-Slave function sequence is as follows:

1) Host enters Master mode. The sensor is already in Slave mode.

Figure 4-1 Communications Option Jumpers

Opt B

10K10K

To M a t ri x

Opt A

L H H L

Interface TypeX0OPB (Pin 14)X0OPA (Pin 13)

SPI, Slave onlyLowLow

UARTHighLow

SPI, Master/SlaveLowHigh

ParallelHighHigh

2) The host pulls SS’ low, then transfers one byte of command to the sensor via MOSI, then releases SS’ to float high again.

3) For 2-byte functions, (2) is repeated with m50us spacings between bytes.

4) The host immediately places its SPI port into Slave mode, floating SCK and MOSI’; SS’ stays floating.

5) When the sensor has a command echo or data to send back, it puts its SPI register in Master mode, taking control over MOSI and SCK. SS' remains floating.

6) The sensor pulls SS’ low, then clocks out its response byte to the host, then floats SS’ high again.

7) The sensor repeats (6) as necessary for multiple byte responses.

8) The sensor returns to slave mode.

After the transmission sequence, the SPI lines float high or are left to float in an indeterminate state (MOSI) until the next transmission sequence is initiated by the host. The host should wait for >1ms after a sequence before initiating another transmission sequence.

See Section 3.15, page 10, for a description of the Alert pin which can be used to reduce communication traffic.

Figure 4-2 SPI Connections

Slave-Only Master-Slave

Host MCU

P_IN

P_OUT

SCK SCK

MOSI MOSI

Vdd

T60

DRDY SS

MISOMISO

Host MCU QT60

SCK SCK

MOSI MOSI

DRDY SS

MISOMISO

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DRDY

{from sensor}

{from host}

SCK

{from host}

MOSI

{from host}

MISO

{from sensor}

SCK

MOSI

Figure 4-3 SPI Slave-Only Mode Timing

dr3

7 6543210

7 6543210 7 6543210

Invalid Data

7 6543210

dr1

Optional Byte 2Host Command Byte 1 Null Dummy Data Null Dummy Data

7 6543210 7 6543210

Invalid Data Response Data or Echo Nth Response Data

dr2

Figure 4-4 SPI Master/Slave Mode Timing

7 6543210 7 6543210 7 6543210 7 6543210

Command Byte 1

from Host to sensor

Optional Byte 2

from host to sensor

dr1

Response Byte or Echo

from sensor to host

{N = command dependent}

dr3

Nth Byte from sensor

{N = command dependent}

SS, SCK, MOSI originate from Host SS, SCK, MOSI originate from sensor

Floating

Figure 4-5 UART Timing

dr1

{from host}

{from sensor}

Command Byte 1

from host to sensor

76543210S

Optional Byte 2

from host to sensor

4.5 UART Interface

Refer to Figures 4-1 and 4-5.

UART communications requires only 2 wires, TX and RX to communicate with a host device. All communications must be

Table 4-1 Typical Tdr1 Response Delays (100µs sample ramp)

Setup - Put (affect 1 key)

Setup - Put (affect 8 keys)

Setup - Put (affect 16 keys)

Lock reference Level (L)

Calibrate command (all keys)

Get key errors (E)

Get keys pushed (K)

All other commands

dr3

76543210S

Response Byte or Echo

from sensor to host

Nth Byte from sensor

{N = command dependent}

76543210S

initiated by the host. The baud rate is determined by Setup ^Q (page 25); the maximum baud rate with a 12MHz oscillator is 57.6K. UART communications uses the following settings:

Burst Spacing

2ms1ms500µsFunction Type

10ms10ms10ms 20ms20ms20ms 65ms65ms65ms

65ms65ms65ms 500µs500µs500µs 450µs450µs450µs 350µs350µs350µs 350µs350µs350µs

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Baud rate 9,600 - 57,600 Data length 8 bits Parity None Stop bits 1 Host command space, Tcm m 50µs Response delay to host, Tdr1 Table 4-1,

also, Sec. 6

Multi-byte return spacing, Tdr3 10µs to 2ms

The actual baud rate is determined by Setup ^Q (page 25).

A UART command may consist of one or two bytes with a m50us delay between command bytes. At the end of a full command, the host must await a response from the sensor.

The sensor may take some time to process the host command and respond. When it does so, it sends back its data. For multi-byte responses, the bytes will be sent at intervals which may be somewhat irregular depending on the request and the processing load of the sensor. The host must be prepared to accept the sensor data as it comes or there can be a data overrun in the host. If the data returns

too quickly for the host to accept it, the baud rate should be lowered.

A typical UART communication sequence is as follows:

1) Host sends a byte to the sensor.

2) For 2-byte functions, a m50us delay is inserted by the host and then the second byte is sent.

3) If the sensor has a command echo or data to send back, it does so. The delay from step 2 to step 3 is shown in Table 4-1. The delay between successive response bytes (if they occur) is parameter Tdr3 noted above.

4) The sensor repeats (3) as necessary for multiple byte responses.

5) The sensor waits for the next command.

The host should wait for >1ms after a sequence before initiating another transmission sequence to be sure that the sensor has completed any residual activities from the prior command. Commands that are sent to the host prematurely will be ignored.

4.6 Sensor Echo and Data Response

The devices respond to each and every valid command from the host with at least one return byte. In the case of functions that do not send data back to the host, the part returns the command itself as an echo, but only after the function has been processed to completion; this also holds for 2-byte functions where the second byte is an operand: in these cases the

return byte is an echo of the command, not the operand.

One important exception to this is the recalibration command ‘b’ which returns an acknowledgment immediately rather than prior to the actual recalibration.

Commands that return data do not send back a command echo. If desired, the command byte can be verified via the 'l' (lowercase L) function; see page 25.

The host should not transmit a new command until the last command has been processed and responded to completion, plus 1ms.

Commands that are not recognized are ignored, and the host should monitor for timeouts to detect these conditions. If this occurs a new command should not be sent until the specified timeout condition has expired.

The maximum timings shown in Table 4-1 and Section 6-5 are guaranteed provided that the part is operating within its burst timing limitations described in Section 5.7. If the burst timing is in violation, the response time to a command may take considerably longer.

4.7 Parallel Scan Port

The parallel port can be used to directly replace an electromechanical or membrane keyboard. The port is electrically equivalent to a 4x4 switch matrix with the exception that the response to a host scan requires up to 100µs. The XS inputs (pins 19..22) are active high; only one XS line should ever be driven high at a time (except for error scan, noted below); the

Figure 4-6 Filtering; SPI Slave-Only Connections

10K

1nF

10K

(MS not shown)

100

22pF

47pF

220

QT60161 Circuit

X drives (1 of 4 shown)

Y Lines (1 of 4 shown)

DRDY

SCK

MISO

MOSI

RESET

Figure 4-7 Filtering; SPI Master-Slave Connections

1nF

10K

(MS not shown)

QT60161 Circuit

100

22pF

220

47pF

X drives (1 of 4 shown)

Y Lines (1 of 4 shown)

DRDY

SCK

MISO

MOSI

RESET

Recommended Values of Ra & Ca for Figures 4-6 and 4-7

Host MCU

P_IN

P_OUT1

SCK

MISO

MOSI

P_OUT2

Host MCU

SCK

MISO

MOSI

P_OUT

CaRaSPI Clock Rate

47pF6803MHz 120pF1,000750kHz 270pF1,000187.5kHz 470pF2,20093.75kHz

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output response is found on the YS lines (pins 23..26), and these are also active high. The bit pattern found on the YS lines indicates any keys that are touched; like a real matrix, the device can set multiple bits on the YS lines.

The host should scan to individual lines XS0..XS3. XS0 maps to matrix drive line X0 (pin 13). The response on YS0 maps to matrix line Y0. Thus, the scan port logic exactly mimics the wiring and scanning of the matrix keys.

The parallel scan port operates on a continuous basis, but is slower to react when either serial port is in operation. If either serial port is operational, the scan port updates with every acquisition burst, i.e. 16 times during a complete scan of the matrix.

For a full-time higher speed scan port response, it should be enabled as the sole interface via the option jumper settings shown in Figure 4-1. The port itself is found on pins 19 through 26 (Figure 3-2). In this dedicated mode, the scan port outputs within 100µs of receiving a scan input from the host.

Error scan: The host can extract error information from the scan port by setting all XS lines to logical '1' simultaneously. The part then returns a high level on any YS lines corresponding to Y matrix lines having key errors. Thus a single YS bit, if high, could indicate errors on any or all of 4 keys. Errors are reported for the following conditions:

a. Key(s) are currently recalibrating b. Key(s) tried to calibrate 5 times and failed each time c. Key(s) signal references are under- or over- limit

It is not possible to determine the cause of the error or specific key(s) in error via the parallel scan port.

eeprom. As intentional writes in Put mode should only occur during manufacture, it is normally safe to assume that eeprom changes during normal run mode are errors.

The host can also periodically test the checksum of the eeprom as a backup mechanism to the bit 4 error flag.

The uppercase ‘L’ command, Lock Reference Levels, also writes data to eeprom, and this data also has the potential to become corrupted. This data is also backed up in Flash so that it can be recovered, and an error in this data will also set bit 4 and also alter the checksum. Also, the ‘L’ command only operates if the device is in Put mode as a further protection.

Flash memory has a limit of 1,000 write cycles, so copy-to-Flash should not be used often.

4.8 Eeprom Corruption

The device stores its Setup data in an internal eeprom which can be readily altered via Put mode commands. Sometimes noise on Vdd, the SPI lines or Reset pin can cause eeprom corruption which can be difficult or inconvenient to correct.

The device should always be left in Get mode to prevent spurious commands from corrupting the eeprom. The Get command should ideally be repeated every second or so to ensure that if noise on the SPI lines causes a false Put mode command that it does not last long. Preferably, the ‘l’ command (lowercase ‘L’) should be used to verify that the Put command has succeeded.

Flash backup: The part backs up the entire eeprom array into onboard Flash rom after one or more Setup write commands have been issued and the part is then reset. During normal operation the part constantly compares the Flash area with the eeprom array to ensure the two sections match. If an eeprom error is detected, the device sets an error flag (bit 4) in the general device status byte (Command ‘7’, page 19) which can be read by the host device. The LED output also becomes active. If the bit 4 error flag is set, the host should immediately induce a device reset.

Bit 4 is also set if an intentional write has been made to eeprom, but not yet copied into Flash via the reset process. It is perfectly acceptable to continue altering any number of Setup parameters prior to doing the reset, ignoring this bit.

During power up or after a reset, the device compares the Flash area with eeprom, and if there is a discrepancy the eeprom is refreshed from Flash, unless an intentional write was detected in which case the Flash is updated from the

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5 Commands & Functions

The command structure is designed to minimize control and data traffic. All repetitive data and status commands from the host are single-byte, and most commands result in singlebyte device responses. Behavioral setup commands involve multiple bytes but these are infrequently used.

Special 'scope' commands exist to restrict subsequent commands to a specific key or range of keys. This control structure permits most matrix keys, which are usually identical in shape and size, to be programmed 'in bulk' using a 'global' scope command, followed by a scope restriction to specific key(s), followed by more key programming, to prevent the need for tedious key-by-key programming across an entire matrix.

There are four types of commands:

Direction - Determine whether subsequent commands are used to get data from or put data to the part;

Scope - Restrict the range of effect of subsequent commands to a specific set of keys;

Status - Cause the part to respond with key information, such as detections, signals, error codes, and the like;

Setup - Modify functionality such as burst length, threshold levels, drift compensation characteristics, etc.

Supervisory - Special functions such as diagnostics, calibration, etc. which affect the part as a whole.

All command types can be intermixed. Even during normal device operation it is possible to use Setup and Supervisory functions to alter key behavior on the fly. There is no special 'setup mode'.

Get/Put, Scope, and many Supervisory functions are volatile and do not persist after a power down or reset cycle. Some Supervisory commands require that the part be reset in order for the new settings to take effect.

Note that the Setup functions write to eeprom and require extra time for a response back to the host. Also note that as with all eeprom memories there is a recommended lifetime limit to the number of writes; this limit is 100,000 cycles.

Command functions are summarized in Section 5-6.

It is highly advised to test the device checksum (command ‘6’, page 18) or individual settings or the general device status (‘7’) once Setups have been programmed into the part, each time the part is powered up and periodically while running.

The part backs up all eeprom locations into Flash, from which data is restored automatically following a reset if eeprom corruption is detected. The part should also be reset after any Put command(s) in order to force the copy of eeprom data into Flash. See Section 4.8.

5.1 Put / Get Direction Commands

Setup commands can be used to either send control information to the part for programming into its internal eeprom, or to extract the current setting of this information. The same Setup function can do either. To accomplish this the device relies on direction control via the Get and Put commands. In Get mode, a Setup command will return information. In Put mode, the behavior of the device is altered, and often a second operand byte must be sent.

The powerup or reset default mode is Get. The current Get/Put mode persists until countermanded by a different Get/Put command or until the device is reset or powered off.

It is advisable to use Put mode only when actually writing Setups to the device, which will happen infrequently; the part should normally be left in Get mode. Get mode acts as a lock to prevent accidental changes to the internal eeprom.

Multiple direction commands of the same type (g, g, g, g ...) are harmless and can be used to insure that the part does not accidentally enter Put mode for a prolonged period, for example due to noise glitches on the SPI lines. The 'g' command can be repeated every few seconds.

g 0X67 - GET C

Scop

Lowercase 'G'. The 'g' command causes the device to treat all subsequent Setup commands as 'Gets'; after, when a Setup command is received from the host the part will respond by sending back the current status of that Setup parameter.

The 'g' command is always single-byte and echoes back itself.

p 0X70 - PUT C

Lower case 'p'. The 'p' command causes the device to treat all subsequent Setup commands as 'Puts'; after, when a 2-byte Setup command is received from the host the part will respond by programming in the desired parameter for the key(s) which are affected.

The 'p' command is always single-byte and echoes back itself.

OMMAND

Bytes / Cm

OMMAND

2nd Byte Ran

Return

0x67n/a1n/aPut

n/an/an/an/aGet

Returns2nd Byte RangeBytes / CmdScope

0x70n/a1n/aPut

n/an/an/an/aGet

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5.2 Scope Commands

The host should always set the scope parameter when initializing the part during normal operation as well as during setup. Scope commands are persistent and apply to all subsequent functions that are affected by scope, until a different scope command is issued. On powerup or after reset the device defaults to scope = 'all keys'.

Many functions only address one key regardless of the current scope; in these cases the key being addressed is always the key last set by the ‘s’ or ‘x’ and ‘y’ commands. If the ‘s’ command was last set to key 9, then even though the ‘S’ command was issued afterwards the one-key scope will remain key ‘9’. Similarly if ‘x’ was set to 2 and ‘y’ to 3, then the one-key scope will remain key x=2 / y=3 (key #14). This rule operates for either Put or Get commands.

Key numbering convention: The numbering of keys goes by row then column. For example, the key in row X=3, column Y=1 (X3Y1) is key 7. The formula for conversion of an X-Y location to a key number is:

key number = X_row + (Y_column x 4)

Row and column numbers are per Fig. 1-5. Keys are acquired in this same burst sequence, i.e. X0Y0, X1Y0, X2Y0 etc.

s 0X73 - S

Lowercase 'S'. Targets a specific individual key for all further functions that are affected by scope. The second byte must contain a binary key number from 0..15.

S 0X53 - ALL K

Uppercase 'S'. Addresses all keys in the matrix for all further functions that can target a group of keys.

x 0X78 - ROW K

Lowercase 'X'. Targets keys in a specific row for functions that can address key groups. The second byte must contain a row number from 0..3.

y 0X79 - C

Lowercase 'Y'. Targets keys in a specific column for functions that can address key groups. The second byte is a binary column number from 0..3.

PECIFIC KEY SCOPE

Scop

Bytes / Cm

EYS SCOPE

Bytes / Cm

EYS SCOPE

OLUMN KEYS SCOPE

Bytes / Cm

2nd Byte Ran

Return

0x730x00..0x0F2n/aPut

n/an/an/an/aGet

Return

0x53n/a1n/aPut

n/an/an/an/aGet

Returns2nd Byte RangeBytes / CmdScope

0x780x00..0x032n/aPut

n/an/an/an/aGet

Return

0x790x00..0x032n/aPut

n/an/an/an/aGet

5.3 Status Commands

Status commands cause the sensor to report back information related to keys and their signals.

It is not necessary to set the part to Get mode with these commands, although it is advised to leave the part in Get mode as a normal precaution (see Section 5.1)

0 0X30 - S

Numeric '0'. Returns the signal level in 16-bit unsigned binary for one key whose location is determined by scope. The least significant byte is returned first.

Note that the signal direction is inverted: decreasing values correspond to more touch due to the physics of key detection described in Section 1.1.

1 0X31 - D

Numeric '1'. Returns the value {Reference - Signal} in unsigned 8-bit binary for one key whose location is determined by scope. If Signal > Reference, the result is truncated to zero. The return value is also limited to 255 (0xFF).

Increasing amounts of this value correspond to increasing amounts of touch as the sign of signal is inverted (see 0x30 above).

2 0X32 - R

Numeric '2'. Returns the Reference value in unsigned 16-bit binary for one key whose location is determined by scope. The least significant byte is returned first.

5 0X35 - D

Numeric '5'. Returns the Detection Integrator counter value for one key whose location is determined by scope. This function is useful primarily for circuit diagnostics.

6 0X36 - E

Numeric '6'. Returns the entire eeprom checksum. This function is useful primarily for diagnostics and should periodically be used to check for valid eeprom contents.

The checksum should be computed when the entire device's settings, including the locked reference levels ('L' command) are known. The host can then periodically test the checksum to validate eeprom integrity. If needed, the eeprom can then

IGNAL FOR SINGLE KEY

Scop

ELTA SIGNAL FOR SINGLE KEY

EFERENCE VALUE

ETECTION INTEGRATOR COUNTS

Scop

EPROM CHECKSUM

Scop

tes / Cm

# Bytes Rtn

Return

n/an/an/a n/aPut

0..0xFFFF211Get

Returns# Bytes RtndBytes / CmdScope

n/an/an/a n/aPut

0x00..0xFF111Get

Returns# Bytes RtndBytes / CmdScope

n/an/an/a n/aPut

0..0xFFFF211Get

Return

n/an/an/a n/aPut

0x00..0xFF111Get

Return

n/an/an/an/aPut

0x00..0xFF11n/aGet

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be reprogrammed by the host or the device can be reset to allow the eeprom to be updated from Flash memory (see Section 4.8).

The checksum is a simple 8-bit carry fold-back type. Changes to multiple Setups can generate identical checksums. Changes to one location only will always produce a different checksum. An identical change to 2, 4, 8, or all 16 keys is more prone to generating an identical checksum. A unique checksum can be obtained again by altering any Setup for another key (i.e. an unused key) to be different.

After any Setups change, the checksum will not be valid until after the device has been reset.

Note that the status byte returned by the ‘7’ command contains a bit that is set if there is an error in eeprom data; this feature operates independently of the checksum command.

There is no put version of the command.

7 0X37 - G

Section 2.11, p. 7

Numeric '7'. Returns the part's general status byte which is a 4-bit pattern as follows:

Bit 0: 1= one or more keys are in detection Bit 1: 1= one or more keys are recalibrating Bit 2: 1= one or more keys are reporting errors Bit 3: 1= sync fail; the part is not synchronized to an

Bit 4: 1 = Eeprom / Flash contents discrepancy

Higher bits report as 0's and are not used.

This command can be used as a general 1-byte status response; if one or more bits are set, the host can take further relevant action to narrow down the specific issue, such as which key is being touched or in error, via other commands.

<SP> 0X20 - S

Space character. Same function as 0x30 above except returns a group response for 4 keys (if Scope = row or column) or 16 keys (if Scope = 'all keys'). If no group scope has been selected, returns data for all keys (32 bytes).

Two bytes are returned for each key; the least significant byte is always returned first.

ENERAL DEVICE STATUS

Scop

external source (if in that mode; see Section 3.14).

Scop

tes / Cm

IGNAL LEVELS FOR GROUP

tes / Cm

# Bytes Rtn

Return

n/an/an/a n/aPut

0x00..0x1F11n/aGet

Return

n/an/an/a n/aPut

0..0xFFFF8 or 3214, 16Get

" 0X22 - R

Double quote character. Same function as 0x32 above except returns a group response for 4 or 16 keys depending on scope. If no group scope has been selected, returns data for all 16 keys (32 bytes).

% 0X25 - D

Percent character. Same function as 0x35 above except returns a group response of 4 bytes (Scope = row or column) or 16 bytes (Scope = 'All keys'). If no group scope has been selected, returns data for all 16 keys.

e 0X65 - E

Section 2.11, p. 7

Lowercase 'E'. Returns the error byte for a selected key defined by the 's' command. A 4-bit pattern is returned:

F: 1= failed last full recalibration attempt R: 1= key is in process of full recalibration H: 1= key reference is high (above normal bounds) L: 1= key reference is low (below normal bounds) u: undefined

Refer also to Section 2.10.

F, Bit 0 is set if it failed to calibrate properly during a forced recalibration. The sensor will automatically make 5 sequential attempts at recalibration before setting this flag.

R, Bit 1 is set if the key is in the process of a full recalibration. When bit 1 is set, bits 2 and 3 are cleared.

H, Bit 2 when set indicates that the key's reference level has exceeded the upper boundary described in Section 2.8 and as defined by Command ^N (page 23).

L, Bit 3 when set indicates that the key's reference level falls below the lower boundary described in Section 2.8 and as defined by Command ^O (page 23).

If either H or L are set, it means that the key is probably defective.

EFERENCE LEVELS FOR GROUP

Scop

ETECT INTEGRATOR COUNTS FOR GROUP

Scop

RROR CODE FOR SELECTED KEY

tes / Cm

# Bytes Rtn

Return

n/an/an/a n/aPut

0..0xFFFF8 or 3214, 16Get

Return

n/an/an/an/aPut

0x00..0xFF4 or 1614, 16Get

Returns# Bytes RtndBytes / CmdScope

n/an/an/a n/aPut

0x00..0x0F111Get

b0b1b2b3b4b5b6b7

FRHLuuuu

! 0X21 - D

Exclamation character. Same function as 0x31 above except returns a group response for 4 or 16 keys depending on scope. If no group scope has been selected, returns data for all 16 keys (16 bytes). The values returned are limited to the range 0..255.

ELTA SIGNALS FOR GROUP

Scop

tes / Cm

# Bytes Rtn

Return

0x00..0xFF4 or 1614, 16Get

n/an/an/a n/aPut

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4b5

s#Bytes

dBy

Y0Y

4b5

©Quantum Research Group Ltd.

E 0X45 - E

RROR CODES FOR GROUP

Scop

tes / Cm

# Bytes Rtn

Return

n/an/an/a n/aPut

0x00..0xFF1 or 411, 4, 16Get

Section 2.11, p. 7

Uppercase 'E'. Returns general error codes for a range of keys defined by scope. Returns either 1 or 4 bytes depending on whether a single key, row, column, or entire matrix are selected.

The bitfields for single key scope are the same as for 'e' above.

The bitfields for a single row (X) are:

b6b7

3----

b0b1b2b3b

0Y1Y2

The bitfields for a single column (Y) are:

b0b1b2b3b4b5b6b7

X0X1X2X3----

The bitfields for a global response are:

b6b7

X1Y0

X2Y0

X3Y0

----byte1

X3Y1

----byte2

X3Y2

----byte3

X3Y3

----byte4

X2Y1

X2Y2

X2Y3

X1Y1

X1Y2

X1Y3

b0b1b2b3b

X0Y0

X0Y1

X0Y2

X0Y3

Byte 1 is the first returned byte in the sequence.

In all the above examples a '1' in a bit position indicates that there is some type of error associated with the key. The use of the 'e' command (or 'E' with scope set to a specific key) will specify the nature of the error.

k 0X6B - R

EPORTING OF FIRST TOUCHED KEY

Scop

tes / Cm

Rtn

Return

n/an/an/a n/aPut

0x00..0xFF11n/aGet

0x4B - Key Touch Reporting for Group

Scop

tes / Cm

# Bytes Rtn

Return

n/an/an/a n/aPut

0x00..0xFF1 or 411, 4, 16Get

Section 2.11, p. 7

Uppercase 'K'. Returns 1 or 4 bytes depending on the current scope. The byte(s) returned contain a bit pattern which indicates touched keys. A scope of a single key, a row or a column will return one byte. A scope of all keys will return 4 bytes.

The bitfields for a single key are:

b0b1b2b3b4b5b6b7

key-------

The bitfields for a single row (scope is X) are:

b6b7

b0b1b2b3b

1Y2Y3----

The bitfields for a single column (scope is Y) are:

b0b1b2b3b4b5b6b7

X0X1X2X3----

The bitfields for a global report are:

b6b7

X1Y0

X2Y0

X3Y0

----byte1

X3Y1

----byte2

X3Y2

----byte3

X3Y3

----byte4

X2Y1

X2Y2

X2Y3

X1Y1

X1Y2

X1Y3

b0b1b2b3b

X0Y0

X0Y1

X0Y2

X0Y3

Byte 1 is the first returned byte in the sequence.

In all the above examples a '1' in a bit position indicates that the key is touched; a '0' indicates no touch.

Section 2.11, p. 7

Lowercase 'K'. Returns a byte that indicates which (if any) key has been touched. The byte is structured as follows:

b0b1b2b3b4b5b6b7

k0k1k2k3---m

Bits are used as follows:

m - if '1', indicates that yet another key is active k0..k3 - indicates the key number of a first detected key,

in the range 0..15 (0x00..0x0F).

If a reported key drops out while other keys are active, 'k' will report one of the other active keys, but there is no rule for which of the next keys gets reported in k0..k5.

If the byte returned has a value of 255 (0xFF), then no key has been detected.

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5.4 Setup Commands

Setup functions are those that alter the behavior a key or a group of keys. The setups are programmed into eeprom locations in the part and ordinarily do not need to be reprogrammed once set. However it is possible to change a setup while the device is in normal operation without interrupting the sensing function of the part.24

Setup functions alter the internal eeprom, and this requires a much longer time to complete than other commands; see Table 4-1.

Setup 'put' commands become effective immediately after the echo response of the command byte unless otherwise noted; some setups require that the key(s) being altered be recalibrated with the 'b' command (page 24) before they take effect.

^A 0X01 - N

Section 2.1, p. 5

Ctrl-A. In Put mode, the command followed by a setting is programmed into eeprom for the key(s) affected by scope.

1, 4, or 16 keys may be affected. Valid decimal values are:

45678101215

17 20 25 30 35 45 55 64

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

This controls key sensitivity by setting the counts of signal delta needed to cause a detect. Higher = less sensitive. Numbers should be 6 or greater under most conditions to reduce the probability of noise detection. Numbers greater than 20 indicate that the burst length is probably too high. This setup interacts with Burst Length (^F).

^B 0X02 - P

Section 2.2, p. 5

Ctrl-B. In Put mode, the command followed by a setting is programmed into eeprom for the key(s) affected by scope. 1, 4, or 16 keys may be affected. Valid decimal values are:

45678101215

17 20 25 30 35 45 55 64

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

This setup controls the ability of a key to recalibrate quickly should the signal transition positive quickly, as when a touch is prolonged enough to cause a recalibration, and when the key is then 'untouched'. This condition can also be caused by a foreign object being removed from a key. The value should normally be set between 6 and 10 counts. If the value is very

EGATIVE DETECT THRESHOLD

ReturnsByte 2 RangeBytes / CmdScope

0x010x04..0x4021, 4, 16Put

0x04..0x40n/a11Get

OSITIVE DETECT THRESHOLD

ReturnsByte 2 RangeBytes / CmdScope

0x020x04..0x4021, 4, 16Put

0x04..0x40n/a11Get

high, the key will still recover by means of the drift compensation process, albeit more slowly.

^C 0X03 - N

Section 2.3, p. 5

Ctrl-C. In Put mode, the command followed by a setting is programmed into eeprom for all keys only. The value should be from 0 to 3, representing hysteresis as follows:

0: 50% 1: 25% 2: 12.5% 3: 0% (no hysteresis)

Values other than the above will be rounded down.

The percentage is the distance from the threshold level to the reference level. The hysteresis level is always closer to the threshold point than to the reference point. 25% is a reasonable value under most conditions.

As this parameter is common to all keys, Put and Get operations send or return only one byte.

^D 0X04 - P

Section 2.3, p. 5

Ctrl-D. Identical in operation to ^C above except this applies to positive 'detections' used to recalibrate the sensor (see ^B above for details). Uses same hysteresis values as ^C above.

^F 0X06 - B

Section 3.5, p. 8

Ctrl-F. In Put mode the command sets the burst length of one or more keys, according to the current scope. Valid decimal values are:

012345710 12 15 20 25 30 40 50 64

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

^F sets the length of the acquisition burst on a key by key basis. This setting is directly proportional to signal gain. This setup interacts with Negative and Positive Threshold (^A and ^B). Increasing ^F can allow for higher threshold levels and more robust signals, at the expense of increased radiated emissions and reduced Cx load capacity.

Special condition: If the value for ^F for a key is set to zero the burst disabled and the key will not function; the key will report back with an error code. The timing for the 'phantom burst' will be preserved so that overall key scan timing will remain unchanged.

EGATIVE THRESHOLD HYSTERESIS

OSITIVE THRESHOLD HYSTERESIS

Scop

URST LENGTH

Bytes / Cm

Byte 2 Ran

ReturnsByte 2 RangeBytes / CmdScope

0x030x01..0x03216Put

0x01..0x03n/a116Get

Return

0x040x01..0x03216Put

0x01..0x03n/a116Get

ReturnsByte 2 RangeBytes / CmdScope

0x060x00..0x4021, 4, 16Put

0x00..0x40n/a11Get

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^G 0X07 - B

Section 3.8, p. 9

Ctrl-G. In Put mode, sets the spacing between successive acquire bursts for the entire matrix.

The second byte indicates the spacing to be set according to the following table:

0: 500µs (0.5ms) 1: 1000µs (1ms) 2: 2000µs (2ms)

Values higher than 2 will be truncated to 2.

Longer delay times equate to slower matrix scanning. At lower delay times (faster rep rates) there can be conflicts with long burst lengths and long conversion times which will prevent proper operation; see also Section 3.6, and Section

5.7.

Burst spacing also affects recalibration time; see Section

2.10.

The scope for this function is always 'all keys'.

^H 0X08 - N

Section 2.4, p. 5

Ctrl-H. In Put mode, sets the rate of drift compensation used during periods of non-detection, in the negative signal direction. Valid decimal values are:

1234681012

15 20 25 33 45 60 75 100

Values other than the above will be rounded down.

These numbers correspond to the amount of drift compensation applied, in 100ms/count of reference change, for signals which are negative with respect to the reference level, i.e. in the same direction as legitimate detections. Higher numbers equate to slower drift compensation. Overcompensation (too fast) can result in the suppression of legitimate detections. Under-compensation can result in inadequate compensation for rapid environmental changes. Values of 15 to 45 (1.5 to 4.5 secs/count) are considered normal under most conditions.

Drift compensation does not occur while the signal has passed below the negative threshold level or subsequently remained below the negative hysteresis level.

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

The scope in Put mode can be one key, a row or column, or all keys.

URST SPACING

Scop

Bytes / Cm

EGATIVE DRIFT COMPENSATION RATE

Byte 2 Ran

Return

0x070x00..0x02216Put

0x00..0x02n/a116Get

ReturnsByte 2 RangeBytes / CmdScope

0x080x01..0x6421, 4, 16Put

0x01..0x64n/a11Get

^I 0X09 - P

Section 2.4, p. 5

Ctrl-I. Same as ^H above in all respects, except operates only when the signal is positive with respect to the reference level, i.e. in an abnormal direction. It is usually desirable to set this rate much faster than for ^H, i.e. to a lower number. Valid decimal values are:

1234681012

15 20 25 33 45 60 75 100

Values other than the above will be rounded down.

Values of 4 to 10 (0.4 to 1.0 secs/count) are considered suitable for most systems.

Positive drift compensation continues to operate even if the signal has exceeded the positive threshold.

^J 0x0A - N

Section 2.6, p. 6

Ctrl-J. In Put mode, sets the detection integration limit for one or more keys according to scope.

The unit of measure is a burst, i.e. a setting of 5 means that a detection must be sensed 5 bursts in sequence. A burst for a key occurs once every complete matrix scan. The second byte must be one of the following values (shown in decimal):

0123571015

20 32 45 60 90 123 175 255

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

This setup can be used as a noise filter, or as a mechanism to intentionally slow down key reaction time in order to require a long user touch.

Special condition: If the value for ^J is set to zero the key is disabled, but the burst for the key is still generated.

OSITIVE DRIFT COMPENSATION RATE

Scop

Bytes / Cm

EGATIVE DETECT INTEGRATOR LIMIT

Bytes / Cm

Byte 2 Ran

0x00..0xFF21, 4, 16Put

Return

0x090x01..0x6421, 4, 16Put

0x01..0x64n/a11Get

Return

0x0

0x00..0xFFn/a11Get

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©Quantum Research Group Ltd.

^K 0x0B - P

Section 2.7, p. 6

Ctrl-K. In Put mode, sets the delay until recalibration, timed from when the signal first crosses the positive threshold.

The second byte controls the delay in 100ms increments, and must be one of the following valid values:

0123571015

20 32 45 60 90 123 175 255

Values other than the above will be rounded down. As an example, a value of 60 will cause a 6-second delay.

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

Special condition: If ^K is set to zero this feature is disabled and the key will never auto-recalibrate on positive transitions; however drift compensation will still operate.

^L 0x0C - N

Section 2.5, p. 6

Ctrl-L. In Put mode, sets the delay until recalibration, timed from when the signal first crosses below the negative threshold as defined by ^A.2.5

The second byte represents the delay in 100ms increments, and must be one of the following valid values:

0123571015

20 32 45 60 90 123 175 255

Values other than the above will be rounded down. As an example, a setting of 85 will cause delays of 6 seconds.

In Get mode the function returns a single value only; if scope is set to row, column, or all, only the value for the lowest ranking key in the group will be returned.

Special condition: If the value for ^L is set to zero this feature is disabled and the key will never auto-recalibrate after a prolonged touch.

^M 0x0D - I

Section 3.7, p. 9

Ctrl-M. In Put mode, sets the amount of time between individual pulses in a burst.

The second byte must be in the range of 1 to 10 decimal; other values will be ignored. The setting applies to all keys.

The value corresponds to the timing between pulses within a burst, in microseconds. For example, a setting of 5 will set the pulse spacing to 5 microseconds.

In Get mode the function returns the current value of ^M.

OSITIVE RECALIBRATION DELAY

Scop

Bytes / Cm

EGATIVE RECALIBRATION DELAY

Bytes / Cm

NTRA-BURST PULSE SPACING

Bytes / Cm

Byte 2 Ran

Return

0x0B0x00..0xFF21, 4, 16Put

0x00..0xFFn/a11Get

Return

0x0C0x00..0xFF21, 4, 16Put

0x00..0xFFn/a11Get

Return

0x0D0x01..0x0A216Put

0x01..0x0An/a116Get

Intra-burst pulse spacing controls the fundamental frequency of the burst and can have a strong effect on radiated emissions from the matrix control panel. It can also have an effect on susceptibility to external EMI if the external fields are close in periodicity to the burst spacing.

^N 0x0E - P

Section 2.8, p. 6

Ctrl-N. In Put mode, sets the amount of tolerable positive deviation in the reference level for all keys, in tenths of a percent, with regard to the 'locked' reference value for each key. The setup is global in nature and affects all keys equally.

Valid values are from 0 to 255 decimal. The percentage applied is one tenth the operand's decimal value.

In Get mode the function returns the current setting of ^N.

This setup is used to define the limit of possible positive reference deviation with respect to a factory setting, which is used in turn to set an error flag for key(s) whose reference level rises above the designated error band. If for example this setting is set to 50, and the device is calibrated and reference levels are locked (see command 'L', Lock Reference Levels, page 24) into the part by the OEM, then in the future if the reference level of a key should rise 5% over its Locked reference level then the key will report back an error flag via commands 'e' or 'E'.

Guardbands can be used to detect circuit faults as well as extremes of temperature or moisture on the circuitry.

Special condition: If the value is set to zero, this feature is disabled.

^O 0x0F - N

Section 2.8, p. 6

Ctrl-O. In Put mode, sets the amount of tolerable negative deviation in the reference level for all keys, in tenths of a percent, with regard to the 'locked' reference value for each key. The setup is global in nature and affects all keys equally.

Valid values are from 0 to 255 decimal. The percentage applied is equal to the decimal value divided by 10, thus, a value of 20 equates to a 2% decrease (i.e. the lower boundary becomes 98% of the locked reference level).

In Get mode the function returns the current setting of ^M.

This setup is identical in nature to ^N except that it governs negative reference deviations.

Special condition: If the value is set to 0, this feature is disabled.

OSITIVE REFERENCE ERROR BAND

Scop

Bytes / Cm

EGATIVE REFERENCE ERROR BAND

Bytes / Cm

Byte 2 Ran

Return

0x0E0x00..0xFF216Put

0x00..0xFFn/a116Get

Return

0x0F0x00..0xFF216Put

0x00..0xFFn/a116Get

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^P 0x10 - A

Section 2.9, p. 6

Ctrl-P. In Put mode, instructs logic for the keys specified by the current scope to suppress a pending touch detection under certain signal conditions.

Valid 2nd byte values for this function are:

0: AKS off {default} 1: AKS on

In Get mode, the command will return a single byte according to the current scope rules (Section 5.2).

AKS functions to suppress detections from water films which can 'spread' a touch signal from the touched key to adjacent keys.

AKS is also useful for panels with tightly spaced keys, where a fingertip can partially overlap an adjacent key. This feature will act to suppress the signals from the unintended key(s).

AKS only operates across keys that have been AKS-enabled; signal strength comparisons are not made with nonAKS-enabled keys.

Unused keys with burst lengths of zero are also ignored for purposes of AKS.

DJACENT KEY SUPPRESSION

Scop

Bytes / Cm

(‘AKS’)

Byte 2 Ran

Return

0x100x00, 0x0121, 4, 16Put

0x00, 0x01n/a11Get

5.5 Supervisory / System Functions

Supervisory functions report or control miscellaneous functions that affect overall chip control, testing, or diagnostics. All supervisory functions ignore scope except where noted.

6 0X36 - E

See page 18.

L 0x4C - L

Section 2.8, p. 6

Uppercase 'L'. This is a put-only command that locks the reference levels of the device into eeprom for all keys, for boundary checking purposes over the product's life.

The whole command – 'L' followed by a null (0x00) - must be received within 100ms without any intervening byte, or the command will fail. The part must be in Put mode for this command to work.

The scope of this command is always 'all keys'.

This function records to eeprom the signal reference for all keys. The locked reference levels are used to compute boundary checks immediately after the command has finished. The results of this command to not take effect until the part has been reset.

Due to the large number of bytes written to eeprom by this command, there is a significant delay from the second byte until the return echo is sent back to the host.

This command should be used only during production. There is no get version of the command.

EPROM CHECKSUM

Returns# Bytes RtndBytes / CmdScope

n/an/an/an/aPut

0x00..0xFF11n/aGet

OCK REFERENCE LEVELS

Returns2nd ByteBytes / CmdScope

0x4C0x00216Put

n/an/an/an/aGet

b 0x62 - R

Section 2.10, p. 7; Section 3.13.

Lowercase 'B'. This is a put-only command that causes the keys selected by scope to recalibrate. The part must be in Put mode for this command to work.

The return byte is sent before the keys have calibrated. While keys are in recalibration, status of the keys can be determined using the 'e' or 'E' commands.

If 'b' is sent while key(s) are already in the middle of recalibration, the affected key(s) will abandon the old calibration cycle and start a new one.

There is no get version of the command.

ECALIBRATE KEYS

Scop

Bytes / Cm

2nd Byt

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Return

0x62n/a11, 4, 16Put

n/an/an/an/aGet

dBy

l 0x6C - R

Lowercase 'L'. This get-only command reports back with the value of the prior command received by the part. The command also reports back any erroneous commands, allowing the host device to verify that a command was correctly received.

If this command is repeated, the second and subsequent instances of 'l' will report back with 0x6C.

There is no put version of the command.

r 0x72 - R

Section 3.11, p. 9

Lowercase 'R'. This put-only command hard-resets the part. The command 0x72 must be followed by a null (0x00) within 100ms or the command will fail. The part must be in Put mode for this command to work.

A reset occurs about 16ms after the echo byte 0x72 is transmitted back to the host. The part will resume communication and sensing in accordance with the timing shown in Section 3.13.

If for some reason the part is unable to send back the echo character 0x72, the command will fail.

There is no get version of the command.

V 0x56 - R

Uppercase 'V'. This get-only command returns the part version number.

There is no put version of the command.

W 0x57 - R

Uppercase 'W'. This get-only command returns the part signature as follows:

0x10 (16 decimal)

There is no put version of this command.

Z 0x5A - E

Section 3.14, p. 9

Uppercase 'Z'. This put-only command forces the device to enter sleep mode. The command 0x5A must be followed by a

ETURN LAST COMMAND CHARACTER

Scop

ESET DEVICE

Scop

ETURN PART VERSION

NTER SLEEP

tes / Cm

Bytes / Cm

ETURN PART SIGNATURE

# Bytes Rtn

2nd Byt

Return

n/an/an/an/aPut

0x00..0xFF11n/aGet

Return

0x720x002n/aPut

n/an/an/an/aGet

Returns# Bytes RtndBytes / CmdScope

n/an/an/an/aPut

0x00..0xFF11n/aGet

Returns# Bytes RtndBytes / CmdScope

n/an/an/an/aPut

0x1011n/aGet

Returns2nd ByteBytes / CmdScope

*0x5A, 0x5A0x002n/aPut

n/an/an/an/aGet

null (0x00) within 100ms or the command will fail. The part must be in Put mode for this command to work.

The command returns 0x5A immediately before going to sleep, and a second 0x5A upon waking up.

If for some reason the device is unable to transmit the first return ‘Z’ character back to the host, for example due to the host not releasing the SS line, the part will completely reset after about 2 seconds.

The part will reawaken after a logic low is detected for 10µs on pin 11 (RST’ pin, see Section 3.11). The device then sends a second ‘Z’ back to the host, and resumes from its prior state before it went to sleep without the need for recalibration. The device resumes in Get mode only.

There is no get version of the command.

^Q 0x11 - D

Section 4, p. 11

Ctrl-Q. This is a put-only command that sets the UART baud rate and the SPI clock rate. All timings assume a 12MHz oscillator. The part must be in Put mode for this command to work.

SPI Settings -

The acceptable values of the operand for SPI use are:

0: 93.75 kHz 1: 187.5 kHz 2: 750 kHz 3: 3 MHz

These values define the maximum SPI clock rate in Master mode (part originates the clock).

Note that when the part is receiving data, the host can send to the device at rates up to 3MHz even if the rate setting of ^Q is slower.

Refer to Sections 4.3 and 4.4 for SPI timing details.

New settings do not become effective until the device has been powered off and back on again or after the reset (‘r’) command.

UART Settings -

The acceptable values of the operand for UART use are:

0: 9600 baud 1: 14400 baud 2: 19200 baud 3: 38400 baud 4: 57600 baud

There is no get version of this function.

Refer to Section 4.5for UART details.

New settings do not become effective until the device has been powered off and back on again or after the reset (‘r’) command.

ATA RATE SELECTION

Scop

Bytes / Cm

2nd Byte Ran

Return

0x110x00..0x042n/aPut

0x00..0x04n/a1n/aGet

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^R 0x12 - O

Section 3.16, p. 11

Ctrl-R. In Put mode, controls the oscilloscope sync function of Pin 43. The settings of this function are:

0: off {factory default} 1: on

When on, Pin 43 outputs a pulse that brackets the acquire burst(s) for the keys targeted by scope. Without this it is virtually impossible to view signals on an oscilloscope corresponding to a specific key.

Pin 43 idles low and pulses high during a sync pulse.

^R is volatile, that is, it does not persist after a power down.

^W 0x17 - N

Section 3.14, p. 9

Ctrl-W. In Put mode, sets whether the noise sync feature is enabled or disabled. The part must be in Put mode for this command to work.

The settings are:

0: off {factory default} 1: on

This function has global scope. The default value is 0 (off).

In Get mode this function returns the current setting of ^W.

The setting of ^W does not become effective until the device has been powered off and back on again or after the reset (‘r’) command has been issued.

SCILLOSCOPE SYNC

Scop

Bytes / Cm

OISE SYNC

2nd Byte Ran

Return

0x120x00, 0x0121, 4, 16Put

0x00, 0x01n/a11, 4, 16Get

ReturnsByte 2 RangeBytes / CmdScope

0x170x00, 0x012-Put

0x00, 0x01n/a1-Get

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5.6 Function Summary Table

Direction Commands

Get0x67g

Put0x70p

Scope Commands

Status Commands

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all subsequent Setup commands become 'Gets'

all subsequent Setup commands become 'Puts’

Get ModePut Mode

Operand

P/GDescriptionNameHexChar

Bytes/PutScope Page

Range

0x671-P

0x701-P

0x730x00..0x0F2-Ptargets a specific key in range 0..15Set one key scope0x73s

0x531-Ptargets all keys in the matrixSet all keys scope0x53S

0x780x00..0x032-Ptargets keys in a designated row, range 0..3Set row keys scope0x78x

0x790x00..0x032-Ptargets keys in a designated column, range 0..3Set column keys scope0x79y

ScopeReturns

Bytes

returned

Return

range

0..0xFFFF21Gget signal strength for 1 key signal for 1 key0x300

0..0xFF11Gget Reference-Signal for 1 key delta signal for 1 key0x311

0..0xFFFF21Gget Reference level for 1 key reference for 1 key0x322

0..0xFF11Gget detect integrator for 1 key Det Integrator for 1 key0x350

0..0xFF1-Gget eeprom checksum of entire eepromeeprom checksum0x366

0..0x1F1-Gget device status of entire devicegeneral device status0x377

0..0xFFFF8, 324, 16Gget signal for group signals for group0x20<sp>

0..0xFF4, 164, 16Gget Reference-Signal for group delta signals for group0x21!

0..0xFFFF8, 324, 16Gget References levels for group references for group0x22“

0..0xFF4, 164, 16Gget detection integrators for group Det integrator for group0x25%

0..0x0F11Gget error code for 1 keyerror code for 1 key0x65e

0..0x0F1, 41, 4, 16Gget error bits for group error codes for group0x45E

0..0xFF--Gget indication of first touched keyreport 1st key0x6Bk

0..0x0F1, 41, 4, 16Gget indication of all touched keysreport touches for group0x4BK

Default setting

Get

undefined

Setup Commands

Negative threshold0x01^A

Positive threshold0x02^B

Negative hysteresis0x03^C

Positive hysteresis0x04^D

Burst length0x06^F

Burst spacing0x07^G

Neg drift comp rate0x08^H

Pos drift comp rate0x09^I

Neg det int limit0x0A^J

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Pos recal delay0x0B^K

Neg recal delay0x0C^L

Intra-burst spacing0x0D^M

Pos error band0x0E^N

Neg error band0x0F^O

nal threshold; fewer counts = more sensitive

4, 5, 6, 7, 8, 10, 12, 15, 17, 20, 25, 30, 35, 45, 55, 64

to positive signals for recalibration

sensitivit

4, 5, 6, 7, 8, 10, 12, 15, 17, 20, 25, 30, 35, 45, 55, 64

hysteresis for negative threshold

50%, 25%, 12.5%, 0%

hysteresis for positive threshold

50%, 25%, 12.5%, 0%

sets number of QT cycles / burst; zero disables burst

0, 1, 2, 3, 4, 5, 7, 10, 12, 15, 20, 25, 30, 40, 50, 64

time from start of one burst to start of next burst

rate of drift compensation for ne

0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5,

rate of drift compensation for positive si

0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5,

number of detections required to register a touch,

counted in bursts of detection; zero disables a key.

time required to trigger a recal from a positive signal

excursion in 0.1s increments; zero disables recal.

0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.2,

time required to trigger a recal from a detection, in 0.1s

0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.2,

tolerable positive reference deviation with respect to

Locked reference values, step 0.1%. Zero disables.

tolerable ne

Locked reference values, step 0.1%. Zero disables.

500us, 1ms, 2ms

ative signal swings

2.0, 2.5, 3.3, 4.5, 6.0, 7.5, 10 secs nal swings

2.0, 2.5, 3.3, 4.5, 6.0, 7.5, 10 secs

0, 1, 2, 3, 5, 7, 10, 15, 20, 32,

45, 60, 90, 123, 175, 255 counts

4.5, 6, 9, 12.3, 17.5, 25.5 secs

increments. Zero disables recal.

4.5, 6, 9, 12.3, 17.5, 25.5 secs

period of QT pulses, in microseconds

1, 2, 3, 4, 5, 6, 7, 8, 9, 10us

ative reference deviation with respect to

P/GDescriptionNameHexChar

P/G

P/Gadjacent key suppression feature; 1 = onKey suppression0x10^P

Get ModePut Mode

Operand

Bytes/PutScope Page

Range

0x00, 0x0121, 4, 16

ScopeReturns

Bytes

returned

110x10

Return

range

Default setting

0x3C (9s)0x00..0xFF110x0C0x00..0xFF21, 8, 64

210x0C0x04..0x40110x010x04..0x4021, 4, 16

210x080x04..0x40110x020x04..0x4021, 4, 16

210x01 (25%)0x00..0x031160x030x00..0x03216

210x01 (25%)0x00..0x031160x040x00..0x03216

210x0C0x01..0x40110x060x00..0x4021, 4, 16

220 (500us)0x00..0x021160x070x00..0x02216

220x1E (3s)0x01..0x64110x080x01..0x6421, 4, 16

220x0A (1s)0x01..0x64110x090x01..0x6421, 4, 16

220x030x00..0xFF110x0A0x00..0xFF21, 4, 16

230x0A (1s)0x00..0xFF110x0B0x00..0xFF21, 4, 16

230x020x02..0x0A1640x0D0x01..0x0A216

230 (off)0x00..0xFF1160x0E0x00..0xFF216

230 (off)0x00..0xFF1160x0F0x00..0xFF216

240 (off)0x00, 0x01

Supervisory Commands

Lock references0x4CL

Recal keys0x62b

Reset device0x72r

Sleep0x5AZ

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Data rate0x11^Q

Scope sync0x12^R

Noise sync0x17^W

locks reference levels into eeprom for future boundar

checks. ‘L’ must be followed by 0x00 (null) 100ms after

the command byte

fully recalibrate keys;

return byte is sent prior to calibration

hard reset the device. ‘r’ must be followed by a null within

100ms.

force device into Sleep mode. ‘Z’ must be followed b

null within 100ms. 0x5A returned before and after

entering Sleep

sets the Master mode SPI clock rate and UART rate;

reset via ‘r’ command or hard reset to take effect

SPI: 93.75kHz, 187.5kHz, 750kHz, 3MHz

UART: 9.6k, 14.4k, 19.2k, 38.4k, 57.6k

oscilloscope sync control. 1 = on.

feature is volatile - does not survive reset

noise sync enable; 1 = on

device must be reset to take effect

Get ModePut Mode

Operand

P/GDescriptionNameHexChar

Bytes/PutScope Page

Range

0x002-P

0x4C0x00216P

0x6211, 4, 16P

0x720x002-P

0x5A,

0x5A

ScopeReturns

Bytes

returned

Return

range

0x00..0xFF1-Greturns checksum of internal eepromEeprom checksum0x366

0x00..0xFF1-Gsend back last command byte receivedReturn last command0x6Cl

0x00..0xFF1-Greturns part version numberVersion0x56V

0x101-Greturns part signature numberSignature0x57W

0x00..0x041-0x110x00..0x042-P/G

Default setting

0 (93.75k,

9600)

0 (off)0x00, 0x011-0x120x00, 0x0121, 4, 64P/G

0 (off)0x00, 0x011-0x170x00, 0x012-G/P

5.7 Timing Limitations

The device requires processing time between bursts, as well as time to handle communications with the host. With short burst spacings, long burst lengths, and long intra-burst pulse spacings, the device can simply run out of available processing time. When this happens, burst timing and host communications slow down and become erratic.

Table 5-2 Permissible Burst Lengths (BL’s)

Cs = 4.7nF, Cx = 5pF, Rs = 180K; 100µs ramp time

Burst

Spacing

Max BL

Burst

Spacing

Burst

Spacing

Max BL

Burst

Spacing

Burst

Spacing

It is important that burst spacings be verified on an oscilloscope with an actual keymatrix during development to be certain that the device timings are preserved and are constant. If not, the burst length and/or pulse spacing should be reduced.

= 6µsPulse Spacing = 5µsPulse Spacing = 4µsPulse Spacing = 3µsPulse Spacing = 2µs

Max BL

3050040500505006450064500 641,000641,000641,000641,000641,000 642,000642,000642,000642,000642,000

Max BL

Burst

Spacing

Pulse Spacing = 10µsPulse Spacing = 9µsPulse Spacing = 8µsPulse Spacing = 7µs

Burst

Spacing

Max BL

20500205002550030500 401,000401,000501,000501,000 642,000642,000642,000642,000

Pulse Spacin

Burst

Spacing

5.8 Erratta / Notes

4 April 2003 - The QT60xx5 version 1.05 datasheet erroneously showed negative recalibration timeouts in the range from

1..255 seconds. The correct range is 0.1..25.5 seconds. From datasheet version 1.06 on, this document change has been made. The devices themselves are not affected.

www.qprox.com QT60161B / R1.03

6 Electrical Specifications

6.1 Absolute Maximum Specifications

Operating temp....................................................................... -40OC to +105OC

Storage temp......................................................................... -55

..................................................................................... -0.5 to +5.5V

Max continuous pin current, any control or drive pin.................................................±10mA

Short circuit duration to ground, any pin............................................................infinite

Short circuit duration to V

, any pin.............................................................. infinite

Voltage forced onto any pin..................................................... -0.6V to (Vdd + 0.6) Volts

Frequency of operation......................................................................... 16MHz

Eeprom maximum writes............................................................ 100,000 write cycles

6.2 Recommended operating conditions

VDD................................................................................... +4.75 to 5.25V

Supply ripple+noise.......................................................................5mV p-p max

Cx transverse load capacitance per key.........................................................0 to 20pF

Fosc oscillator frequency.................................................................. 12MHz +/-2%

6.3 DC Specifications

Vdd = 5.0V, Cs = 4.7nF, Freq = 12MHz, Ta = recommended range, unless otherwise noted

Paramete

DDR

DDS

Supply current, sleepI

Acquisition resolutionA

1610

UnitsMaxTypMinDescription

Not including external componentsmA25Supply current, runningI

Not including external componentsµA

V0.8Low input logic levelV

V2.2High input logic levelV

4mA sinkV0.6Low output voltageV

1mA sourceVVdd-0.7High output voltageV

µA±1Input leakage currentI

bits

Drdy, SS’ pinskohms12035Pullup resistorsR

Notes

C to +125OC

6.4 Protocol Timing

Parameter

UnitsMaxTypMinDescription

µS100Parallel port response delayT

µS1,0001Tdr delay from responseT

µS2,00015Multi-byte return spacingTDR3

Notes

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6.5 Maximum Drdy Response Delays

... with adjacent key suppression disabled:

Setup - put (affect 1 key) Setup - put (affect 4 keys) Setup - put (affect 16 keys) Lock reference Level (L) Calibrate command (all keys) Get key errors (E), Get keys pushed (K) All other commands

... with adjacent key suppression enabled:

Setup - put (affect 1 key) Setup - put (affect 4 keys) Setup - put (affect 16 keys) Lock reference Level (L) Calibrate command (all keys) Get key errors (E), Get keys pushed (K) All other commands

Burst Spacing

2ms1ms500µsFunction Type

10ms10ms10ms 20ms20ms20ms 65ms65ms65ms 65ms65ms65ms

1.1ms2ms2ms 1ms2ms1.5ms 1ms1ms1.5ms

Burst Spacing

2ms1ms500µsFunction Type

10ms10ms10ms 20ms20ms20ms 65ms65ms65ms 65ms65ms65ms

1.2ms2ms2.5ms

1.1ms2ms2ms

1.1ms2ms1.5ms

Preliminary Data: All specifications subject to change.

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7 Mechanical

7.1 Dimensions

44 42 40 38 36 34

43 41 3739 35

2 3

6 7

8 9 10

15 17 19 2113

12 14 16 18 2220

32 31 30

28 27

26 25 24

7.2 Marking

Package Type: 44 Pin TQFP

SYMBOL

Min Max Notes Min Max Notes

9.90 10.10 0.386 0.394

0.09 0.20 0.003 0.008

0.45

0.05

0.30

0.80

8.00 0.315

o07 07

Millimeters Inches

12.2111.75 0.458 0.478

0.75

0.15

1.20

0.45

0.80

8.00

BSC

BSC BSC

0.018

0.002

0.012

0.031

0.030

0.006

0.047

0.018

0.031

0.315

MarkingTQFP Part NumberT

QT60161B-AQT60161B-AS-400C to +1050C

SQSQ

BSC

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8 Index

adc, 8 adjacent key suppression, 6, 7, 12, 24, 28, 32 alert output

led, 10, 11

application assistance, 4

block diagram, 5 boundary limits, 19, 23, 29 burst length, 4, 7, 8, 9, 17, 21, 28, 30 burst spacing, 8, 9, 14, 22, 28, 30, 32 burst timing, 15, 30

calibration

recalibration, 5, 6, 7, 9, 10, 17, 19, 21, 23, 24, 29

circuit model, 7 cs, 5, 8, 9

delta signals, 19, 27 detection integrator, 5, 6, 8, 18 direction commands, 17 drdy’, 12 drift compensation, 5, 6, 11, 17, 21, 22, 23 dwell, 7, 9

echo, 12, 13, 15, 21, 24 eeprom checksum, 18, 24 electrostatic shield, 11 emi, 11, 23

rfi, 8, 9, 21

error code, 4, 11, 16, 17, 19, 20, 21, 23 error guardbanding, 23 esd protection, 8, 9, 11

field flow, 4, 8 function summary table, 27

get command, 17 ground plane, 11

hysteresis, 5, 21, 22

intra-burst pulse spacing, 9, 23

key design, 4 key numbering convention, 18 key reporting, 20

led

alert output, 10, 11

lock reference levels, 6, 14, 23, 24

master mode, 12, 13 master-slave mode, 4, 12, 13 miso, 12, 13 mosi, 9, 12, 13

negative detect integrator, 22 negative detect threshold, 21 negative drift compensation, 22 negative hysteresis, 5 negative recalibration delay, 6, 23 negative reference error band, 23 negative threshold, 5, 7, 8, 21, 22, 23 noise, 11, 12 noise filter, 22. see also emi

oscillator, 7, 9, 10, 12, 14, 25 oscilloscope sync, 11, 26

pcb layout, 4, 11 positive detect threshold, 21 positive recalibration delay, 6, 7, 23 positive reference error band, 23 positive threshold, 5, 6, 7, 21, 23 power supply, 11 pulse spacing, 9, 23 put command, 17

qmbtn, 4, 10, 11

recalibrate keys (command), 24 recalibration

calibration, 5, 6, 7, 9, 10, 17, 19, 21, 23, 24, 29

reset, 7, 9, 10, 11, 17, 25, 26 resonator, 7, 9. see also oscillator return last command, 25

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return part signature, 25 rfi

emi, 8, 9, 21

slave mode, 13 sleep mode, 10 spi, 12, 15 spi noise problems, 11

tcm, 12, 15

water films, 24

x-drives, 7, 8

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The specifications set out in this document are subject to change without notice. All products sold and services supplied by QRG are subject to our Terms and Conditions of sale and supply of services which are available online at www.qprox.com and are supplied with every order acknowledgement. QProx, QTouch, QMatrix, QLevel, and QSlide are trademarks of QRG. QRG products are not suitable for medical (including lifesaving equipment), safety or mission critical applications or other similar purposes. Except as expressly set out in QRG's Terms and Conditions, no licenses to patents or other intellectual property of QRG (express or implied) are granted by QRG in connection with the sale of QRG products or provision of QRG services. QRG will not be liable for customer product design and customers are entirely responsible for their products and applications which incorporate QRG's products.

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