ANALOG DEVICES UG-062 Service Manual
Evaluation Board User Guide
UG-062
One Technology Way • P. O . Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel : 781.329.4700 • Fax : 781.461.3113 • www.analog.com
Evaluation Board for AD7843/AD7873 Resistive Touch Screen Controllers
FEATURES
Easy access to the AD7843/AD7873
Connects to any PC USB port
Self-contained evaluation system
Test points for easy access to signals
Touch screen included
PACKAGE CONTENTS
The AD7843/AD7873 evaluation board kit contains the following:
• The AD7843/AD7873 evaluation board
• A USB cable
• A CD with the evaluation software, schematics, and this
user guide
• A 4-wire resistive screen
EVALUATION BOARD BLOCK DIAGRAM
J7-2
3.3V
GENERAL DESCRIPTION
The AD7843/AD7873 evaluation board allows the user to
evaluate all features of the AD7843/AD7873. The evaluation
software allows the user to change the settings on the AD7843/
AD7873. The users can connect the touch screen to the J3 connector,
or use the on-board variable resistors, to evaluate the touch screen
function.
VOLTAGE
0.1µF
1.0µF TO 10µF
(OPTIONAL)
REGULATOR
MAIN
BATTERY
TEST POINT
3/
V
IN
CS
PENIRQ
GND
Figure 1.
BAT
BUSY
+V
DOUT
K
DCL
CC
X+
CC
+
Y
V
REF
J2
OPTIONAL
R-C
X+
Y+X–
J1-1
J1-2
J3-1
TOUCH
SCREEN
NOTES
1. THE AUX AND V
See the last page for an important warning and disclaimers. Rev. 0 | Page 1 of 12
Y–
J1-3
J1-4
J3-4
J3-3J3-2
PINS ONLY APPLY TO THE AD7873. THE IN3 AND IN4 PINS O NLY APPLY TO THE AD7843 .
BAT
IN4/AUX
X–
+V
AD7843/
AD7873
Y–
DIN
TEST POINTS
TEST POINTS
3.3V
3.3V
CS
INT1
INT2
MISO
SCLK
MOSI
HOST
INTERFACE
SPI
08633-001
UG-062 Evaluation Board User Guide
TABLE OF CONTENTS
Features .............................................................................................. 1
Package Contents .............................................................................. 1
General Description ......................................................................... 1
Evaluation Board Block Diagram ................................................... 1
Revision History ............................................................................... 2
Evaluation Board .............................................................................. 3
Setting Up the Evaluation Board ................................................ 3
Evaluation Board Description .................................................... 3
Evaluation Board Hardware ............................................................ 4
Connector Function Descriptions ............................................. 4
Link Function Descriptions ........................................................ 4
REVISION HISTORY
12/09—Revision 0: Initial Version
Indicator LED Descriptions .........................................................4
Evaluation Board Software ...............................................................5
Installing the Software ..................................................................5
Running the Software ...................................................................5
Evaluation Demonstration ...............................................................6
Single Conversion Block ...............................................................6
Continuous X-Y Conversion .......................................................7
Touchscreen ...................................................................................8
Schematics ..........................................................................................9
ESD Caution................................................................................ 12
Rev. 0 | Page 2 of 12
Evaluation Board User Guide UG-062
EVALUATION BOARD
SETTING UP THE EVALUATION BOARD
Follow these steps to set up the AD7843/AD7873 evaluation
board:
• Install the evaluation software (CD) before connecting
the board.
• Plug the USB connector from the USB port on your PC
into the mini-USB socket on the evaluation board. The
power indicator LED on the board should turn on.
• Ensure that all switches and links are in their default
positions.
• Start the AD7843/AD7873 evaluation software.
EVALUATION BOARD DESCRIPTION
The AD7843/AD7873 evaluation board allows the user to evaluate
all features of the AD7843 and AD7873. The board is powered via
the USB connection to the host PC. The evaluation software
allows data to be read from and written to the
AD7843/AD7873. Install the evaluation software on the PC before
plugging in the board.
The evaluation board contains the following main components,
which are also shown in the functional block diagram (see
Figure 1):
• AD7843/AD7873 IC
• USB microcontroller IC, CY7C68013-CSP
• LED indicators for power and
• EEPROM for USB initialization information
• Connector for USB interface
• Connector for touch screen
• Screw-top connectors for the following signals: X−, Y+,
X+, Y−, +V
• Test points for the following signals: DOUT, DIN, DCLK,
PENIRQ
CS
,
The printed circuit board (PCB) schematics are shown in Figure 6
and Figure 7.
, V
, and GND
CC
REF
, BUSY, +VCC, and V
PENIRQ
.
BAT
Rev. 0 | Page 3 of 12
UG-062 Evaluation Board User Guide
EVALUATION BOARD HARDWARE
CONNECTOR FUNCTION DESCRIPTIONS
Table 1.
Name Mnemonic Description
J6 USB interface Plug the USB cable directly from the PC into this connector. It is a type USB Mini-B socket.
J13-1 Power
J13-2 AGND An external ground can be connected via the J13-2 connector.
J7-2 EXT_VREF
J2 AUX The J2 connector can be used to apply a signal to the AUX input on the AD7843/AD7873.
J5 EXT_BAT
J3 Touch screen
J1 Touch screen
LINK FUNCTION DESCRIPTIONS
Power can be supplied to the board by either the USB cable or the power connector, J13. If L5 is in Position B,
power is supplied via the USB cable. If L5 is in Position A, power is supplied from the J13-1 connector.
Connector J7-2 can be used to apply a signal to the VREF input on the AD7843/AD7873. L6 must be in
Position A for this connector to be linked to the AD7843/AD7873. If L6 is in Position B, 3.3 V is applied to
the VREF input.
Connector J5 can be used to apply a signal to the VBAT input on the AD7843/AD7873. L7 must be in Position B
for this connector to be linked to the AD7843/AD7873.
The touch screen included with the demonstration kit can be connected directly into the AD7843/AD7873
demonstration board using this connector. Connect as follows: X− to J3-1, Y+ to J3-2, X+ to J3-3, and Y− to J3-4.
This connector can be used to connect a touch screen to the AD7843/AD7873. Connect as follows:
X− to J1-1, Y+ to J1-2, X+ to J1-3, and Y− to J1-4.
Table 2.
Default
Name Mnemonic
L1 X+ A
L2 Y+ A
L3 X− A
L4 Y− A
L5 Input power B
L6 REF input A
L7 BAT input A
Position Description
This jumper selects the X+ input on the AD7843/AD7873. If the jumper is in Position A, the X+ input
comes from the J1-3 or J3-3 touch screen connectors.
This jumper selects the Y+ input on the AD7843/AD7873. If the jumper is in Position A, the Y+ input
comes from the J1-2 or J3-2 touch screen connectors.
This jumper selects the X− input on the AD7843/AD7873. If the jumper is in Position A, the X− input
comes from the J1-1 or J3-1 touch screen connectors.
This jumper selects the Y− input on the AD7843/AD7873. If the jumper is in Position A, the Y− input
comes from the J1-4 or J3-4 touch screen connectors.
This jumper selects the input power for the evaluation board. If the jumper is in Position A, power
for the board must be supplied through the J13-1connector. If the link is in Position B, the USB
connection supplies the power for the board.
This jumper selects the input signal to the reference input on the AD7843/AD7873. If the jumper is
in Position A, REF is connected to Pin 2 of the J7 (J7-2) connector. An input voltage can then be
connected to J7-1. If the link is in Position B, REF is connected to 3.3 V.
This jumper selects the input signal to the VBAT input on the AD7843/AD7873. If the jumper is in
Position B, VBAT is connected to the J5 connector. An input voltage can then be connected to J5. If
the link is in Position A, VBAT is connected to a variable resistor, R9. The user can vary R9 to change
the input voltage on the V
INDICATOR LED DESCRIPTIONS
Table 3.
Name Mnemonic Description
D1
PENIRQ
This LED indicates when lit (green) that the
pin. The maximum resistance of R9 is 10 kΩ.
BAT
PENIRQ
interrupt is active on the AD7843/AD7873.
Rev. 0 | Page 4 of 12
Loading...