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19-2680; Rev 0; 10/02
MAX1234 Evaluation System/Evaluation Kit
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 integrated touch screen and keypad interface. Windows (R) 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 personal computer. Order the EV kit (MAX1234EVKIT) if the 68HC16MODULE-DIP module has already been purchased with a previous Maxim EV system or for custom use in other C-based systems. o o o o o o
Features
Proven PC Board Layout Complete Evaluation System Convenient Test Points Provided On Board Fully Assembled and Tested 4 4 Keypad Included Interfaces to Common 4-Wire Resistive Touch Screens
Evaluates: MAX1233/MAX1234
Component Lists
Table 1. MAX1234 EV System
PART MAX1234EVKIT 68HC16MODULE-DIP QTY 1 1 DESCRIPTION MAX1234 EV kit 68HC16 C module
MAX1234 Stand-Alone EV Kit
The MAX1234 EV kit provides a proven PC board layout to facilitate evaluation of the MAX1234. It must be interfaced to appropriate timing signals for proper operation. Connect 5V and ground return to terminal block TB1 (see Figure 8). Refer to the MAX1234 data sheet for timing requirements.
Table 2. MAX1234 EV Kit
DESIGNATION QTY C1, C2 C3,C4 C5 FB1 H1, H2, H3, H4 H5 H6 2 2 1 1 4 1 1 DESCRIPTION 10F, 10V tantalum capacitors 0.1F, 10V X7R ceramic capacitors Open Ferrite bead 7-pin headers 0.100in header, 2 10 0.5mm ZIP SMT flex cable connector Digi-Key HKF20CT-ND Hirose FH12A-20S-0.5SH 2 20 right-angle socket SamTec SSW-120-02-S-D-RA 3-pin jumper Socket pins for 4 4 keypad Digi-Key ED5009 pin receptacles 4 4 keypad, Grayhill Series 96, front mount Digi-Key GH5003-ND Digi-Key GH5004-ND MAX1234EGT (28-pin QFN) MAX1615EUK MAX1840EUB or MAX1841EUB 0.200in screw terminal block PC board 3.5in software disk MAX1234 data sheet MAX1234 EV kit data sheet 68HC16MODULE-DIP data sheet
MAX1234 EV System
The MAX1234 EV system operates from a user-supplied 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.
J1 JU1 K1
1 1 8
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, without the C module.
K1
1
U1 U2 U3, U4, U5 TB1 None None None None None
1 1 3 1 1 1 1 1 1
Ordering Information
PART MAX1234EVKIT MAX1234EVC16 TEMP RANGE 0C to +70C 0C to +70C INTERFACE TYPE User supplied Windows software
Windows is a registered trademark of Microsoft Corp.
________________________________________________________________ Maxim Integrated Products
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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.
MAX1234 Evaluation System/Evaluation Kit 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 9pin 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 connector 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 automatically 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 software, 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-digital 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 corresponding Read or Write button. (Registers that cannot be written do not have a write button.) The ADC, DAC, KEY, and GPIO buttons open an application-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 controls the touch-screen digitizer, the auxiliary voltage inputs, the temperature measurement, and the reference voltage. By default, the software automatically waits for BUSY and then reads updated data after writing 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 software 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 calibrated 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.
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Note: The evaluation software's main window provides direct access to all registers, and controls the interrupt response. Figure 1. EV Software's Main Window
Digital-to-Analog Converter Window
The MAX1234: Digital to Analog Converter window controls 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.
Click Read KPDATA1 to read data masked by the column 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 C1-C4 checkboxes and clicking Write column mask. Masked keys are grayed on the keypad display.
GPIO Window
The GPIO screen reassigns the keypad pins to generalpurpose input and output. Keypad pins R1-R4 and C1-C4 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 output (see Figure 6).
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).
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Note: The evaluation software's main window provides direct access to all registers, and controls the interrupt response. Figure 2. EV Software's Main Window
Diagnostics Window
The Diagnostics screen performs a battery of tests on the system. From the main window's View menu, activate 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 registers. 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 patterns. The Keypad test checks the KEYIRQ interrupt pin, the R1-R4 and C1-C4 pins, and the keypad controller. The DAC analog output test uses the AUX2 pin to measure 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 support 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.
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Note: The ADC window controls the touch-screen digitizer, the auxiliary voltage inputs, the temperature measurement, and the reference voltage. Figure 3. Analog-to-Digital Converter Window
The EV kit includes a MAX1615 3V/5V linear regulator and a set of MAX1840/MAX1841 level shifters to support 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 approximately 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).
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Note: The DAC window controls the voltage at the DACOUT pin. Figure 4. Digital-to-Analog Converter Window
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Note: The Keypad window controls the 4 4 keypad scanner. Figure 5. Keypad Window
Troubleshooting
Problem: No output measurement. System seems to report zero voltage, or fails to make a measurement. Check VDD and VLOGIC supply voltages. Configure the ADC power-up settings to "always on" by writing binary code 00-0000-01-xx-xx-xxx-x to the ADC Control Register (see Figure 2). Then check the reference voltage using a digital voltmeter. Use an oscilloscope to verify that the BUSY pin is strobed low, indicating that a measurement is performed.
Problem: Measurements are erratic, unstable; poor accuracy. Check the reference voltage using a digital voltmeter. Use an oscilloscope to check for noise. When probing for noise, keep the oscilloscope ground return lead as short as possible, preferably less than 1/2in (10mm). Try increasing the acquisition time or settling time. Try forcing measurements using ADC or KEY mode 00. Try connecting a good quality 0.1F ceramic capacitor between the affected input and ground.
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Note: The GPIO window reassigns the keypad pins to generalpurpose input and output. Figure 6. GPIO Window
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Note: The Diagnostics window performs a battery of tests on the system. To select individual tests, switch the mode from EV Kit Production Test to Diagnostics. Figure 7. Diagnostics Window 8 _______________________________________________________________________________________
MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
CS SCLK DIN BUSY DOUT PENIRQ KEYIRQ
H4 DVDD H1 DVDD AVDD X+ Y+ XYGND 1 AVDD 2 3 4 5 6 7 C4 0.1F 10V 1 2 3 4 5 6 7 C3 0.1F 10V 1 28 CS DVDD AVDD X+ Y+ XYGND BAT1 8 TERMINAL BLOCK TB1-1 TB1-2 1 2 3 4 5 6 7 H2 AVDD R4 BAT2 AUX1 AUX2 REF DACOUT R4 9 10 11 12 13 14 C5 OPEN 2 27 SCLK 3 26 DIN 4 5 6 7
24 25 23 22 BUSY DOUT PENIRQ KEYIRQ C4 C3 C2 C1 R1 R2 R3 21 20 19 18 17 16 15 1 2 3 4 5 R1 6 R2 7 R3 H3 R1 C4 C3 C2 C1 1 2 3 4 5 6 7 8
K1
U1 MAX1234
R1 R2 R3
R4 R3 R2
1 CONNECTOR N.C. J1-5 N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. J1-34 J1-39 J1-40 N.C. N.C. N.C. J1-38 J1-31 J1-35 J1-27 J1-29 +5V J1-36 J1-7 J1-8 J1-37 +5V +5V J1-1 J1-2 J1-3 J1-4 AVDD FB1 C2 10F 10V DVDD J1-6 +12V 2
IN
J1-9 J1-10 J1-11 J1-12 J1-13 J1-14 J1-15 J1-16 J1-17 J1-18 J1-19 J1-20 J1-21 J1-22 J1-23 J1-24 J1-25 J1-26 J1-28 J1-30 J1-32 J1-33
U2
GND
SHDN
5
X1 DVDD
X2
X3
X4
X5 1 LOGO H6-1 H6-2 H6-3 H6-4 H6-5 H6-6 H6-7 H6-8 H6-9 H6-10 H6-11 H6-12 H6-13 H6-14 H6-15 H6-16 H6-17 H6-18 H6-19 H6-20
MAX1615
H5-1 1 4 JU1 5/3 2 (FB) 3 H5-2 H5-3 H5-4 H5-5 H5-6 1 2 3 4 5 DATA DVCC CIN RIN SHDN I/O 10 9 8 7 6 DIN DVDD SCLK CS H5-7 H5-8 H5-9 H5-10 H5-11 H5-12 6 7 8 9 10 6 7 8 +5V 9 10 GND
3 OUT C1 10F 10V
U3 MAX1840
VCC CLK RST GND
U4
RST CLK VCC I/O GND
SHDN RIN
5 4 3 2 1
DVDD KEYIRQ DOUT DVDD
H5-13 H5-14 H5-15 H5-16 H5-17 H5-18
MAX1840
CIN DVCC DATA
U5
RST CLK VCC I/O
SHDN RIN
5 4 3 2 1
DVDD BUSY PENIRQ DVDD
H5-19 H5-20
MAX1840
CIN DVCC DATA
Figure 8. MAX1234 EV Kit Schematic _______________________________________________________________________________________ 9
MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
X+
Y+
300 100 TO 500 100 TO 500
X-
Y-
Figure 9. Touch-Screen Equivalent Circuit
Figure 10. MAX1234 EV Kit Component Placement Guide--Component Side 10 ______________________________________________________________________________________
MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Figure 11. MAX1234 EV Kit PC Board Layout--Component Side
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MAX1234 Evaluation System/Evaluation Kit Evaluates: MAX1233/MAX1234
Figure 12. MAX1234 EV Kit PC Board Layout--Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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