Quantum Research Group QMatrix QT60486 User manual
E6486
User Manual
The New Vision of Touch™
QT60486 and QT60326
QMatrix™ IC
Evaluation and
Development Kit
OVERVIEW
This kit is designed for evaluation and development of QT60486 and QT60326-based glass
touch matrix circuits. It includes all circuitry and materials required to make a fully-
functioning, 48-key matrix touch control. This board has an RS232 serial interface that
allows connection to a PC for function setup and data viewing. The E6486 makes use of
QmBtn™ software, which is included.
The QT chip in this board uses two interfaces: SPI for high-speed synchronous
communications or RS232 for communications with a PC. The RS232 interface is the primary
interface used for evaluation.
A 16-pin header connector on the end of the board allows connection to a matrix panel. A 48-
key sample matrix and plastic panel are supplied with the kit. An LED status indicator shows
detection and error states.
For more detailed information about this product, please refer to the QT60486 datasheet.
Materials Provided:
1x E6486 eval board
1x Matrix Panel with 48 keys
1x RS232 serial cable
1x 9v Battery
1x CD-ROM with QmBtn™ software (or get the latest from www.qprox.com/downloads)
1x User Guide
You will also need:
A PC running any recent version of Windows (98, 98SE, NT4, 2000, XP) upwards, with a free RS232 port
(Com 1 or Com 2).
SETUP
After you have prepared the board and matrix, get the unit to run as follows:
1Plug the matrix tail into the board's matrix connector. The matrix panel should be flex-side down
so that you touch the plastic panel, not the flex.
2Connect the E6486 to a PC using the RS232 serial cable (supplied). Make sure the serial port is
not currently used by any other application or driver (like mouse software) and there are no Com
conflicts. The board will work on Com 1 or Com 2.
3Run the QmBtn™ software (on the supplied CD or from www.qprox.com/downloads).
4Apply +8 to +20VDC to the screw terminal block. This can be a 9V alkaline battery or a bench supply.
5The board should start communicating with QmBtn™, and you
will see an array of 48 buttons as shown on the right.
If the board does not communicate with the PC, make sure the jumper
J4 (located next to the power connector) is set on 'UART', then cycle
power off and on again.
If the setups are correct, touching the keys on the panel will cause the
QmBtn™ buttons to depress. The last key touched will leave an 'X' on
the key afterwards. You can open the 'Key Settings' window and look at
the signals from any specific key by clicking with your mouse on the key
representation. You can change the settings for the chosen key or all
keys using the 'Key Settings' window. You can also view all 48 signals
in bar graph form in the 'Signal Levels' window.
QmBtn™ Operation
BOARD PREPARATION
Before powering up, prepare the matrix panel and board using the following steps:
1Place the panel on a bench so that it will be elevated and mechanically stable, otherwise you will
get wildly fluctuating signal levels when you press on the panel.
2Attach the 9V battery snap (or other power leads) to the board's power terminal block.
BOARD DETAILS
Please refer to figure 2 on page 9
Power Terminal
This screw terminal strip is used to power the board. The voltage should be between +8 and +20VDC. Power
should be free from switching noise and short-term fluctuations for best performance. Be sure to check for low
voltage periodically if using a battery; low voltage will cause erratic performance.
RS232 (UART) Connector
This connector provides direct communications between the E6486 and the PC. It allows full control over the
device including calibration and setups. It also allows for real-time supervision of signal, reference and
calibration information. Use a straight-through type cable (supplied) — also known as an extender cable — to
a PC. The RS232 and SPI interfaces cannot operate at the same time.
Matrix Connector
The E6486 has two headers (J2 and J3). The pinout of both ports is described in table 1 (page 7). The header
provides the X-Y scanning of the matrix electrode. X lines drive charge into the matrix, and the Y lines conduct
the charge back out. The keyboard supplied with the kit can be connected directly to J3.
Communication Port Select
The UART port can either come from the RS232 connector or from J1. This
jumper allows the user to select the source of the UART signal.
SPI / UART Direct Port
J1 header gives access to all the signals useful for communicating with the QT60486 or QT60326. The pinout
of the connector is described below:
The QT60486/QT60326 can use either SPI or UART communications modes; it cannot use both at the same
time. The part defaults to SPI mode unless it receives a byte over the UART interface. If a UART byte is
received at any time, the UART interface is enabled and the SPI interface is totally disabled until after the next
device reset.
The QT60486 datasheet contains substantial additional information on communications.
J4 UART Source
RS232 RS232 Connector
DIRECT J1
Pin Description
1 SPI - Data Input
2 Power; +5V
3 SPI - Clock Input
4 SPI - Data Output
5 Reset
6 Supply Ground
7 n.c.
8 n.c.
9 SPI - Data Ready
10 SPI - Slave Select
11 UART - Receive
12 UART - Transmit
13 Wake-up from sleep input / sync input
14 Status Output
J1
MISO
Vcc
SCK
MOSI
/RST
GND
n.c.
n.c.
/DRDY
/SS
Rx
Tx
WS
STATUS
SCHEMATIC DIAGRAM
Figure 1 — Schematic Diagram
Sync/Sleep
This input performs two functions: wake-up from sleep input, or noise synchronization input.
Wake from Sleep via UART: Link this input to the Rx line to enable wake from sleep via UART. In this mode,
the device will wake when a dummy transmission (a null byte) is received from the host over the UART RX
line. The logic level change of the UART RX line is used to create a wakeup logic input to the chip’s WS pin.
Wake from Sleep via SPI: Link this input to MOSI to enable wake from sleep via SPI. In this mode, the device
will wake when a dummy transmission (a null byte) is received from the host over the SPI lines. The logic level
change of the MOSI line is used to create a wakeup logic input to the chip’s WS pin.
External Wake from Sleep: Feed a minimum 5us sync pulse (normal logic high, pulse low) to pin 13 of J1 with
respect to GND to wake the part from a sleep state.
External Noise Sync: Feed a TTL or 5V CMOS synchronization pulse into pin 13 of J1 with respect to GND.
The QT60486 / QT60326 acquisition bursts can be synchronized to an external source of repetitive electrical
noise, such as 50Hz or 60Hz using the Noise Sync feature, which is enabled via Setups. External repetitive
signals are thereby heavily suppressed, since the system and the noise become synchronized and no longer
beat or alias with respect to each other. The sync input triggers the burst for key 0 (X0Y0); the device waits for
the sync signal for up to 100 ms after the end of a preceding full matrix scan (after key #47), then, when a sync
pulse is received, the matrix is scanned in its entirety one time. If no sync pulse is received in 100ms, the part
wakes on its own and re-scans the matrix one time then goes back to sleep. Sync pulses should be spaced no
more than 99ms apart to prevent this from happening.
Reset / Recal Button
This button causes a hard reset and a recalibration of all keys. The recalibrate button in QmBtn™ will also
accomplish a recalibration of all or some keys depending on current Scope. It is also possible to cause a hard
reset via QmBtn™.
Oscilloscope Sync
The ‘scope sync’ test point can be used to synchronize an oscilloscope. When enabled in QmBtn™, this signal
provides a pulse that brackets the chosen burst or bursts, making diagnostics much simpler. With the scope
sync enabled for one key, the X matrix drive signals can be clearly seen.
Status LED
The LED shows touch and error activity. If there is a calibration error or another type of fault, this LED will glow
solid. If the part is working normally, and no keys are detecting, the LED will be off. If one or more keys are
touched, the LED will flicker. The brightness of the flicker will be proportional to the number of keys detecting.
Cs Capacitors
The Cs capacitors, C12, C13, C14, C15, C17, C18 are the charge integrators that are used to detect changes
in key capacitance. Corresponding resistor network RN8 is used to convert the acquired charge to digital form.
These parts are optimal and should not be changed in value without a known reason.
Figure 2 — Board Layout
Table 1 — Matrix Connector Pinout
XMn = X matrix drive pulses (driven by chip)
YMn = Y matrix receive lines (input to chip)
Power
Terminal
Status
LED
Communication
Port Select
SPI/ UART
Direct Port
Oscilloscope
Sync Point
Matrix
Connector
Sampling
Resistor Network
Reset/ Recal
Button
RS232
(UART)
Pin J2 J3
1 YM0 GND
2 YM1 YM2
3 YM2 YM3
4 YM3 YM0
5 YM4 YM1
6 YM5 YM4
7 GND YM5
8 GND GND
9 GND XM0
10 GND XM1
11 XM0 XM2
12 XM1 XM3
13 XM2 XM4
14 XM3 XM7
15 XM4 XM5
16 XM5 XM6
17 XM6 -
18 XM7 -
19 GND -
20 GND -
PCB LAYERS
Figure 3 — Silk Layer
Figure 4 — Top Layer
Figure 5 — Bottom Layer
Board Will Not
Communicate
with PC
Bad Serial Connections
Check/replace serial cable
Bad or Conflicting Com Port on PC
Shut down other tasks that may also be using the same com port IRQ or I/O
address on the PC
Use a different PC
Low Battery or Power Supply Out of Usable Range
Restore power to within correct range
J4 is on the Wrong Setting
Board Will
Not Calibrate
Excess Capacitive Load
Reduce burst length
Reduce Cx loading
Shorted X or Y Matrix Line
Low Power Supply Voltage
Noisy or
Erratic Signal
Noisy Power Supply
Matrix or matrix cable too close to a noise source such as a power line or
switching noise source
Use Noise Sync feature to overcome
Increase distance to noise source
Place grounded shield between noise source and matrix
Ground Loop Interference
Matrix or Matrix Cable not Mechanically Stable
Strong RFI from a Transmitter or Adjacent Digital Product
Insufficient Signal Filtering
Increase burst length and threshold level
Increase the detection integrator level
TROUBLESHOOTER
L Q
www.qprox.com
Corporate Headquarters
1 Mitchell Point
Ensign Way, Hamble
Southampton SO31 4RF
United Kingdom
Tel +44 (0)23 8056 5600
Fax +44 (0)23 8045 3939
Email [email protected]
North America
651 Holiday Drive Bldg. 5 / 300
Pittsburgh, PA 15220
USA
Tel 412-391-7367
Fax 412-291-1015
Copyright © 2004 QRG Ltd
Version 200.180805
All rights reserved
Patented and patents pending
Mouser Electronics
Authorized Distributor
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