19-2345; Rev 0; 02/02 MAX6675 Evaluation Kit Features ♦ Digitizes and Displays Temperature from a Type-K Thermocouple ♦ SPI™-Compatible Serial Interface ♦ Easy-to-Use Menu-Driven Software ♦ Available in an 8-Pin SO Package ♦ Assembled and Tested ♦ Includes Windows 95/98/2000-Compatible Software, Demo PC Board, and Type-K Thermocouple Ordering Information Component List DESIGNATION C1–C4 QTY DESCRIPTION 4 0.1µF, 16V X7R ceramic capacitors Taiyo Yuden EMK107BJ104KA Murata GRM188R71C104KA01 TDK C1608X7R1C104K C5 1 2.2µF, 16V X7R ceramic capacitor Taiyo Yuden EMK316BJ225ML Murata GRM42-6X7R225K016 TDK C3216X7R1C225M J1 1 DB-25 male right-angle connector J2 1 Thermocouple connector, miniature size, type K Omega PCC-SMP-K JU1–JU5 0 Not installed R1 1 470kΩ ±5% resistor U1 1 MAX6675ISA temperature sensor U2 1 MAX1840EUB/MAX1841EUB level translator U3 None 1 MAX1615EUK linear voltage regulator 1 Thermocouple, epoxy-coated tip, -10°C to +80°C, miniature-size male connector, type K Omega TC-PVC-K-24-180 PART TEMP RANGE MAX6675EVKIT 0°C to +70°C IC PACKAGE 8 SO Quick Start Required Equipment Before you begin, the following equipment is needed: • Computer running Windows 95, 98, or 2000 (Note: Windows 2000 requires the installation of a driver; refer to Win2000.pdf or Win2000.txt located on the diskette.) • Parallel printer port (this is a 25-pin socket on the back of the computer) • Standard 25-pin, straight-through, male-to-female cable (printer extension cable) to connect the computer’s parallel port to the MAX6675 EV kit • DC power supply capable of supplying any voltage between 7V and 20V at 100mA Procedure Do not turn on the power until all connections are made. 1) Connect a cable from the computer’s parallel port to the MAX6675 EV kit. Use a straight-through 25pin female-to-male cable. To avoid damaging the EV kit or your computer, do not use a 25-pin SCSI port or any other connector that is physically similar to the 25-pin parallel printer port. Windows is a registered trademark of Microsoft Corp. SPI is a trademark of Motorola, Inc. ________________________________________________________________ Maxim Integrated Products 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. 1 Evaluates: MAX6674/MAX6675 General Description The MAX6675 evaluation kit (EV kit) is an assembled and tested PC board that demonstrates the MAX6675 thermocouple digital temperature sensor. It accepts the input from a type-K thermocouple and converts the temperature to 12-bit data. The MAX6675 EV kit connects to a computer for acquiring the data from the MAX6675. Windows® 95/98/2000compatible software provides a user-friendly interface to display the 12-bit data and convert it to a temperature. The EV kit includes a type-K thermocouple for evaluation up to +80°C. To evaluate the MAX6674, order a free sample of the MAX6674ISA. Evaluates: MAX6674/MAX6675 MAX6675 Evaluation Kit Component Suppliers PHONE FAX Murata SUPPLIER 770-436-1300 770-436-3030 www.murata.com WEBSITE Omega 888-826-6342 — www.omega.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Note: Please indicate that you are using the MAX6675 when contacting these manufacturers. 2) The MAX6675.EXE software program can be run from the floppy or hard drive. Use the Windows program manager to run the program. If desired, you may use the INSTALL.EXE program to copy the files and create icons for them in the Windows 95/ 98/2000 Start menu. An uninstall program is included with the software. Click on the UNINSTALL icon to remove the EV kit software from the hard drive. 3) Connect the 7V to 20V supply to the pads labeled VIN and GND. 4) Turn on the power supply. 5) Start the MAX6675 program by opening its icon in the Start menu. 6) Observe as the program automatically detects the MAX6675 and starts the main program. Detailed Description User-Interface Panel The user interface is easy to operate. Use either the mouse or the Tab key to navigate. Note: Words in boldface are user-selectable features in the software. The program continually polls the device for new temperature data. To disable the continuous polling of data, uncheck the Automatic Read checkbox. Press Read Temp to get the current temperature. General-Purpose SPI Utility There are two methods for communicating with the MAX6675: through the user-interface panel or through the general-purpose SPI utility. This utility (Figure 2) configures SPI parameters such as clock polarity (CPOL), clock phase (CPHA), and chip-select (CS) polarity. The fields where pin numbers are required apply to the pins of the parallel port connector. The utility handles the data only in byte (8-bit) format. Data longer than 1 byte must be handled as multiple bytes. For example, a 16-bit word should be broken into two 8-bit bytes. To write data to the slave device, enter the data into the field labeled: Data bytes to be written. Each data byte should be hexadecimal, prefixed by 0x, and separated with a comma. Press the Send Now button to write the data to the slave. Note: The MAX6675 is a read-only device and cannot be written to. To read data from the slave device, the field: Data bytes to be written: must contain hexadecimal values, includes the same number of bytes as to be read from the slave. For example, to read 16-bit data from the MAX6675, 2 bytes must be written, each prefixed by 0x and separated by a comma (default is 0x00, 0x00). Note: When using the SPI utility, uncheck the Automatic Read checkbox in the main display. Data Logging Evaluating with a Lower Supply Voltage Check the Data Logging checkbox to activate data logging. Data logging saves temperature and status data to a text file that includes a time/date stamp next to each data point. If Automatic Read is enabled, data is sampled at 1Hz; however, the data is logged to the file only if the temperature changes. This slows the growth of the data-logging file. When Automatic Read is disabled, the data is logged each time the Read Temp button is clicked. To stop data logging, uncheck the Data Logging checkbox. The MAX6675 EV kit is configured for operating at 5V. To evaluate the MAX6675 at a lower supply voltage, cut the traces shorting the pins of JU1. Apply the desired voltage (between 3V and 5V) to the VCC pad. Note: A 7V to 20V supply must be connected to VIN to power the MAX1840 level translator. 2 Connecting to a Microcontroller The MAX6675 EV kit can be monitored externally with a microcontroller or other control device by cutting the traces shorting the pins of JU2, JU3, and JU4 and connecting to the pads labeled SCK, CS, and SO. _______________________________________________________________________________________ MAX6675 Evaluation Kit Evaluating the MAX6674 The MAX6675 EV kit can also evaluate the MAX6674. Remove the MAX6675 from the board and install the new part. Select the MAX6674 radio button on the main display of the software. Open Thermocouple Detection To enable the Open Thermocouple Detection, install a shunt on jumper JU6. This connects pin 2 of the MAX6675 to ground. Figure 2. SPI Utility Showing the Settings to Communicate with the MAX6675 EV Kit _______________________________________________________________________________________ 3 Evaluates: MAX6674/MAX6675 Figure 1. Main Display for the MAX6675EVKIT Evaluates: MAX6674/MAX6675 MAX6675 Evaluation Kit VIN 1 SHDN IN 5 U3 C4 0.1µF X_SO X_SO 1 I/O DATA JU2 10 CUT HERE 5V 5V 2 DVCC C2 0.1µF VCC JU5 CUT HERE C3 0.1µF U2 3 CLK CIN OUT R1 470kΩ X_CS SCK JU3 CUT HERE 4 RIN RST 5V 5 GND SHDN 7 JU4 CUT HERE CS 6 1 DB-25 CONNECTOR NC X_SCK J1-2 J1-10 X_CS X_SO J1-11 J1-12 J1-5 2 J2 N.C. T- U1 SO 7 - J1-20 J1-13 8 GND JU6 J1-18 J1-19 NC MAX6675 J1-21 3 + T+ CS VCC SCK 6 VCC J1-6 NC J1-14 NC J1-22 J1-7 NC J1-15 NC J1-23 VCC J1-8 NC J1-16 NC J1-24 5V J1-9 NC J1-17 NC J1-25 4 JU1 CUT HERE 5 C1 0.1µF Figure 3. MAX6675 EV Kit Schematic 4 4 C5 2.2µF 8 X_CS J1-4 5/3 (FB) MAX1840 X_SCK NC 3 9 X_SCK J1-3 MAX1615 2 SO VCC 5V J1-1 GND GND _______________________________________________________________________________________ MAX6675 Evaluation Kit 1.0" Figure 4. MAX6675 EV Kit Component Placement Guide— Component Side Figure 5. MAX6675 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 5 Evaluates: MAX6674/MAX6675 1.0" Evaluates: MAX6674/MAX6675 MAX6675 Evaluation Kit 1.0" Figure 6. MAX6675 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.