General Description
The MAX1234 evaluation system (EV system) consists
of a MAX1234 evaluation kit (EV kit) and a Maxim
68HC16MODULE-DIP microcontroller (C) module. The
MAX1234 is a complete PDA controller with an integrat-
ed touch screen and keypad interface. Windows
95/98/2000 software provides a handy user interface to
exercise the MAX1234's features.
Order the complete EV system (MAX1234EVC16) for
comprehensive evaluation of the MAX1234 using a per-
sonal computer. Order the EV kit (MAX1234EVKIT) if
the 68HC16MODULE-DIP module has already been
purchased with a previous Maxim EV system or for cus-
tom use in other C-based systems.
MAX1234 Stand-Alone EV Kit
The MAX1234 EV kit provides a proven PC board layout
to facilitate evaluation of the MAX1234. It must be inter-
faced to appropriate timing signals for proper opera-
tion. Connect 5V and ground return to terminal block
TB1 (see Figure 8). Refer to the MAX1234 data sheet
for timing requirements.
MAX1234 EV System
The MAX1234 EV system operates from a user-sup-
plied 7VDC to 20VDC power supply. Windows
95/98/2000 software running on an IBM PC interfaces to
the EV system board through the computer's serial
communications port. See the Quick Start section for
setup and operating instructions.
Ordering Information
The MAX1234 software is designed for use with the
complete EV system MAX1234EVC16, which includes the
68HC16MODULE-DIP module together with MAX1234
EVKIT. If the MAX1234 EV software is not used, the
MAX1234EVKIT board can be purchased by itself, with-
out the C module.
Features
o Proven PC Board Layout
o Complete Evaluation System
o Convenient Test Points Provided On Board
o Fully Assembled and Tested
o 4
4 Keypad Included
o Interfaces to Common 4-Wire Resistive Touch
Screens
Evaluates: MAX1233/MAX1234
MAX1234 Evaluation System/Evaluation Kit
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
19-2680; Rev 0; 10/02
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
PART
TEMP RANGE
INTERFACE TYPE
MAX1234EVKIT
0C to +70C
User supplied
MAX1234EVC16
0C to +70C
Windows software
PART
QTY
DESCRIPTION
MAX1234EVKIT
1
MAX1234 EV kit
68HC16MODULE-DIP
1
68HC16 C module
DESIGNATION QTY
DESCRIPTION
C1, C2
2
10F, 10V tantalum capacitors
C3,C4
2
0.1F, 10V X7R ceramic capacitors
C5
1
Open
FB1
1
Ferrite bead
H 1, H 2, H 3, H 4
4
7-pin headers
H5
1
0.100in header, 2
10
H6
1
0.5mm ZIP SMT flex cable connector
Digi-Key HKF20CT-ND
Hirose FH12A-20S-0.5SH
J1
1
2
20 right-angle socket
SamTec SSW-120-02-S-D-RA
JU1
1
3-pin jumper
K1
8
Socket pins for 4
4 keypad
Digi-Key ED5009 pin receptacles
K1
1
4
4 keypad, Grayhill Series 96,
front mount
Digi-Key GH5003-ND
Digi-Key GH5004-ND
U1
1
MAX1234EGT (28-pin QFN)
U2
1
MAX1615EUK
U3, U4, U5
3
MAX1840EUB or MAX1841EUB
TB1
1
0.200in screw terminal block
None
1
PC board
None
1
3.5in software disk
None
1
MAX1234 data sheet
None
1
MAX1234 EV kit data sheet
None
1
68HC16MODULE-DIP data sheet
Table 2. MAX1234 EV Kit
Table 1. MAX1234 EV System
Component Lists
Windows is a registered trademark of Microsoft Corp.
Evaluates: MAX1233/MAX1234
Quick Start
Before you begin, the following equipment is needed:
MAX1234EVC16 (contains MAX1234 EV kit board
and 68HC16MODULE-DIP)
A small DC power supply, such as a 12VDC 0.25A
plug-in transformer, or a 9V battery
An IBM PC-compatible computer running Windows
95/98/2000
A spare serial communications port, preferably a 9-
pin plug
A serial cable to connect the computer's serial port
to the 68HC16MODULE-DIP
Standard 4-wire resistive touch screen.
Do not turn on the power until all connections are
made:
1) Ensure that the MAX1234 EV kit's JU1 jumper has a
shunt installed in the MAX1234 position.
2) Carefully connect the boards by aligning the 40-pin
header of the MAX1234 EV kit with the 40-pin con-
nector of the 68HC16MODULE-DIP module. Gently
press them together. The two boards should be
flush against one another.
3) Connect a 7VDC to 20VDC power source to the C
module at the terminal block located next to the
on/off switch, along the top edge of the C module.
Observe the polarity marked on the board.
4) Connect a cable from the computer's serial port to
the C module. If using a 9-pin serial port, use a
straight-through, 9-pin, female-to-male cable. If the
only available serial port uses a 25-pin connector, a
standard 25-pin to 9-pin adapter is required. The
EV kit software checks the modem status lines
(CTS, DSR, DCD) to confirm that the correct port
has been selected.
5) Install the EV software on your computer by running
the INSTALL.EXE program on the floppy disk. The
program files are copied and icons are created for
them in the Windows Start menu.
6) Turn on the power supply.
7) Start the MAX1234 program by opening its icon in
the Start menu.
8) At the prompt, connect the C module and turn on
its power. Slide SW1 to the ON position. Select the
correct serial port, and click OK. The program auto-
matically downloads its software to the module.
9) Connect the 4-wire resistive touch screen to the X+,
Y+, X-, and Y- pins of the header. For convenience,
a 20-pin 0.5mm flex cable breakout is provided by
headers H5 and H6.
10) Click Demo Touchscreen. The software tracks the
motion of a stylus on the touch screen (see Figure 1).
11) Click Demo Keypad. The software tracks key
presses (see Figure 5).
Detailed Description
of Software
The EV software's main window configures the interrupt
handler and displays the internal registers in binary.
To aid development of custom interrupt-driven soft-
ware, the Interrupt Handler tab (see Figure 1) handles
interrupt request (IRQ) response. Both
PENIRQ and
KEYIRQ can be polled, and a set of checkboxes select
the desired response.
The low-level registers are grouped by function. The
ADC regs tab (see Figure 2) controls the analog-to-dig-
ital converter, including the touch-screen digitizer. The
DAC regs tab controls the digital-to-analog output. The
KEY regs tab is for the keypad, and the GPIO regs tab
is for the general-purpose input/output (GPIO) pins.
Each register can be read or written by clicking the cor-
responding Read or Write button. (Registers that can-
not be written do not have a write button.)
The ADC, DAC, KEY, and GPIO buttons open an appli-
cation-oriented view of their respective functions.
Interrupt response is also handled by the main screen.
Analog-to-Digital Converter Window
The MAX1234: Analog to Digital Converter window con-
trols the touch-screen digitizer, the auxiliary voltage
inputs, the temperature measurement, and the refer-
ence voltage. By default, the software automatically
waits for BUSY and then reads updated data after writ-
ing to the ADC control register (see Figure 3).
For improved accuracy, measure the reference voltage
and enter its value into Actual REF Voltage. This only
affects the BAT1, BAT2, AUX1, AUX2, and temperature
voltage reporting. The MAX1234 code outputs are not
affected. When the REFV control bit is changed, the soft-
ware automatically resets the Actual REF Voltage to 1.0V
or 2.5V, unless Ask before changing REF is checked.
The temperature measurement can be further calibrat-
ed by adjusting Room Temperature centigrade and
"TEMP1 Vroom" for TEMP1 measurements, or by
adjusting "Temp2-Temp1 K/delta V" for Temp2-Temp1
measurements. Refer to the MAX1234 data sheet for
more information on temperature measurement.
MAX1234 Evaluation System/Evaluation Kit
2
_______________________________________________________________________________________
Digital-to-Analog Converter Window
The MAX1234: Digital to Analog Converter window con-
trols the voltage at the DACOUT pin. Enter the DAC
code value between 0 and 255, and click Write DAC.
The DAC can be powered off by clicking DAC Off (see
Figure 4).
For improved accuracy, set the DAC output code to
255 and measure the actual DACOUT voltage. Enter
the full-scale voltage into DAC Full-Scale Voltage to
adjust the reported ideal DAC output voltage.
Keypad Window
The Keypad window controls the 4
4 keypad scanner.
Use the drop-down combo boxes to set up the keypad
control register, then click Write KEY Control. Refer to
the MAX1234 data sheet for suggested usage details
(see Figure 5).
Click Read KPDATA1 to read data masked by the col-
umn mask. Click Read KPDATA2 to read keypad data
masked by the key mask and column mask. Active key
presses are highlighted on the keypad display.
Mask individual keys using the appropriate
R1C1...R4C4 checkboxes and clicking Write key
mask. Or mask an entire column using the C1C4
checkboxes and clicking Write column mask. Masked
keys are grayed on the keypad display.
GPIO Window
The GPIO screen reassigns the keypad pins to general-
purpose input and output. Keypad pins R1R4 and
C1C4 can be individually assigned to GPIO. The
Write GPIO button writes all of the GPIO registers from
the checkboxes. Each GPIO pin can be configured as
an input, a totem-pole output, or an open-collector out-
put (see Figure 6).
Evaluates: MAX1233/MAX1234
MAX1234 Evaluation System/Evaluation Kit
_______________________________________________________________________________________
3
Figure 1. EV Software's Main Window
Note: The evaluation software's main window provides direct access to all registers, and controls the interrupt response.
Evaluates: MAX1233/MAX1234
Diagnostics Window
The Diagnostics screen performs a battery of tests on
the system. From the main window's View menu, acti-
vate Diagnostics. To select individual tests, change the
mode from EV Kit Production Test to Diagnostics.
Scroll to the desired test, check the appropriate boxes,
and click its Test button (see Figure 7).
The Download test downloads the operating code to the
C module, if it is not already running. The Initialize test
verifies power-on defaults values of the MAX1234 regis-
ters. The Readback test verifies the DIN, DOUT, SCLK,
and
CS pins of the serial interface by writing test patterns
to the registers, and then reading back those test pat-
terns. The Keypad test checks the
KEYIRQ interrupt pin,
the R1R4 and C1C4 pins, and the keypad controller.
The DAC analog output test uses the AUX2 pin to mea-
sure the DAC analog output. (Note: AUX2 should be tied
to DAC when performing this test.) The ADC analog
inputs test measures the ADC analog inputs BAT1,
BAT2, AUX1, and AUX2. The ADC touch-screen inputs
test checks the
PENIRQ interrupt pin, the BUSY pin, the
X+/X- and Y+/Y- drivers, and the analog inputs.
Detailed Description
of Hardware
The MAX1234 device under test (U1) requires no sup-
port components except the supply bypass capacitors
(C1, C2). The 4
4 keypad (K1) interfaces directly to
U1. Other styles of keypad can be evaluated by
unplugging K1 and installing a user-supplied keypad.
Commonly available touch screens using 20-pin 0.5mm
flex ribbon cable can be plugged into H6 and then
wired from H5 to the X+, X-, Y+, and Y- pins on the
breakout header. See Figure 8, the MAX1234 EV Kit
Schematic, and refer to the MAX1234 data sheet.
MAX1234 Evaluation System/Evaluation Kit
4
_______________________________________________________________________________________
Figure 2. EV Software's Main Window
Note: The evaluation software's main window provides direct access to all registers, and controls the interrupt response.
Evaluates: MAX1233/MAX1234
MAX1234 Evaluation System/Evaluation Kit
_______________________________________________________________________________________
5
The EV kit includes a MAX1615 3V/5V linear regulator
and a set of MAX1840/MAX1841 level shifters to sup-
port using the 3V MAX1233 with the 5V C.
Touch-Screen Equivalent Circuit
For prototyping purposes, a 4-wire resistive touch
screen can be simulated using two variable resistors
connected by a resistor and a switch. Variable resistor
X, connected between X+ and X-, should be approxi-
mately 100
to 500. Variable resistor Y, connected
between Y+ and Y-, should be approximately 100
to
500
. Connect the center wipers of the two variable
resistors using a fixed resistor of approximately 300
,
simulating the touch resistance. See Figure 9.
Evaluating the MAX1233
The MAX1233 is the 3V version of the MAX1234. Request
a free sample of MAX1233EGT. Using the MAX1233,
replace U1, and move the JU1 shunt to the MAX1233
position. In the software's DAC window, change DAC
Full-Scale Voltage to 2.97V (90% of 3.3V).
Figure 3. Analog-to-Digital Converter Window
Note: The ADC window controls the touch-screen digitizer, the auxiliary voltage inputs, the temperature measurement, and the
reference voltage.
Figure 4. Digital-to-Analog Converter Window
Note: The DAC window controls the voltage at the DACOUT pin.
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