MAX1202EVKIT

19-1197; Rev 0; 3/97 E MODUL 6811D LE B A IL A AV MAX1202 Evaluation Kit The MAX1202 evaluation system (EV system) is a complete, 8-channel data-acquisition system consisting of a MAX1202 evaluation kit (EV kit) and a Maxim 3V 68L11D microcontroller (µC) module. The MAX1202 is a low-power, +5V, 8-channel, 12-bit analog-to-digital converter (ADC) that connects directly to 3V and 5V microprocessors (µPs). Windows 3.1™/ Windows 95™ software provides a handy user interface to exercise the MAX1202’s features. Order the EV system for comprehensive evaluation of the MAX1202 using a personal computer. Order the EV kit if you have already purchased the 68L11D µC module with a previous Maxim EV system, or for custom use in other µC-based systems. The MAX1202 EV kit and EV system can also be used to evaluate the MAX1203. Simply order a free sample of the MAX1203BCPP along with the MAX1202 EV kit. For 3V-only applications, refer to the MAX147 data sheet. ____________________Component List DESIGNATION QTY C1–C8, C13 9 0.01µF ceramic capacitors DESCRIPTION C9, C10, C11, C14, C15 5 0.1µF ceramic capacitors C12 1 4.7µF, 10V tantalum capacitor J1 1 2 x 20 right-angle socket JU1, JU2 2 3-pin jumper blocks JU3 1 2-pin jumper block JU4 0 Open R1–R8 8 300Ω, 5% resistors TP1 1 8-pin header 1 Maxim MAX1202BCPP 1 20-pin socket U2 1 Maxim ICL7660CPA U3 1 78L05 voltage regulator None 1 PC board None 1 Software disk, “MAX1202 EVALUATION KIT” U1 ____________________________Features ♦ Proven PC Board Layout ♦ Complete Evaluation System ♦ Convenient On-Board Test Points ♦ Data-Logging Software ♦ 3V/5V Logic Interface ♦ Fully Assembled and Tested ______________Ordering Information PART TEMP. RANGE BOARD TYPE MAX1202EVKIT-DIP 0°C to +70°C Through-Hole MAX1202EVL11-DIP 0°C to +70°C Through-Hole MAX1202EVL11 ___________System Component List QTY DESCRIPTION MAX1202EVKIT-DIP PART 1 MAX1202 Evaluation Kit 68L11DMODULE 1 68L11D µC Module _____MAX1202 Stand-Alone EV Kit The MAX1202 EV kit provides a proven PC board layout to facilitate evaluation of the MAX1202. It must be interfaced to appropriate timing signals for proper operation. Refer to the MAX1202 data sheet for timing requirements. Cut JU4 and apply the +5V analog supply between the +5V pad and the pad marked GND. Connect the VLOGIC pad to the microprocessor's power supply. Set JU1 to the 2-3 position (VSS = -5V) to allow input signals between ±4V (Table 1). Windows is a registered trademark of Microsoft Corporation. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 Evaluates: MAX1202/MAX1203 _______________General Description Evaluates: MAX1202/MAX1203 MAX1202 Evaluation Kit ______________MAX1202 EV System The MAX1202 EV system operates from a usersupplied 9V to 15V DC power supply. The Maxim 68L11D 3V µC board uses a MAX667 linear regulator to generate the 3V logic supply. The MAX1202 board uses a 78L05 linear regulator to generate its own 5V analog supply. No level translators are necessary because the MAX1202 VL pin is connected to the 3V logic supply. Quick Start Table 1. Jumper Functions ∫ JUMPER JU1 JU2 3) Carefully connect the boards by aligning the EV kit’s 40-pin header with the µC module’s 40-pin connector. Gently press them together. The two boards should be flush against one another. 4) Connect a 9V to 15V DC power source to the µC module at the terminal block located next to the on/off switch, in the upper-right corner of the µC module. Observe the polarity marked on the board. 5) Connect a cable from the computer’s serial port to the µC 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. 6) Start the MAX1202 program by opening its icon in the Program Manager (or Start Menu). 7) The program will prompt module and turn its power position. Select the correct The program automatically to the module. you to connect the µC on. Slide SW1 to the on serial port and click OK. downloads KIT1202.L11 8) Apply input signals to the CH0–CH7 inputs at the right edge of the MAX1202 EV board. Observe the readout on the screen. 2 FUNCTION 1-2 VSS tied to GND 2-3 VSS tied to -5V Open 1) Install the MAX1202 EV kit software on your computer by running the INSTALL.EXE program on the floppy disk. The Windows 3.1 Program Manager (or the Windows 95 Start Menu) copies the program files and creates icons for them. 2) Check the jumper settings on the EV board. Refer to Tables 1 and 2. STATE VSS must be supplied by the user. 1-2 SHDN tied to GND; power-down 2-3 SHDN tied to +5V; internal compensation Open SHDN floating; external compensation Closed REFADJ = +5V; VREF must be supplied by the user. JU3 Open JU4 REFADJ = open; VREF = 4.096V internal reference (MAX1202) Current-sense jumper. The Closed MAX1202 draws its +5V analog (default trace) supply through this trace. Open Do not operate kit with JU4 open. Table 2. Default Jumper Settings JUMPER DEFAULT STATE JU1 2-3 VSS tied to -5V JU2 2-3 SHDN tied to +5V JU3 Open REFADJ = open; VREF = 4.096V internal reference (MAX1202) JU4 Closed The MAX1202 draws its +5V analog supply through this trace. FUNCTION Evaluating the MAX1203 To evaluate the MAX1203, turn off the power to the EV kit, close JU3, and replace U1 with a MAX1203BCPP. Connect the external voltage reference to the VREF pad. No other hardware changes are necessary. Refer to the section Changing the Reference Voltage. _______________________________________________________________________________________ MAX1202 Evaluation Kit Shutdown Power Cycling The MAX1202 can be shut down between conversions to reduce average supply-current demand. From the “Power” menu, select full power-down (FULLPD) or fast power-down (FASTPD) mode. In fast power-down mode, the bandgap reference remains active. The amount of power saved depends primarily on how long the part is off between conversions. The conversion accuracy depends on the power-up delay, the reference capacitor, and the time in power-down. Adjust offtime with the “Delay Between Samples” command. Adjust on-time with the “Power-Up Delay” command. Using an adequate power-up delay ensures conversion accuracy during power-cycling modes. The reference must be allowed enough time to stabilize before the measurement is performed. The “Power-Up Delay” command controls power-up delay. Increase the delay until accuracy is constant. The power-up delay requirement depends on the off-time (delay between samples) and the value of the reference capacitor (C12). The MAX1202 EV kit software performs power-up by starting a conversion in FASTPD mode and discarding the reading. FASTPD mode turns on the reference, but leaves the MAX1202’s other circuitry powered down. An accurate reference-voltage measurement can be performed after the power-up delay is complete. The MAX1203 requires an external reference, so FULLPD mode can always be used, assuming the external reference is always stable when measurements are performed. In this case, set power-up delay to 0. Measuring Supply Current On the EV board, the MAX1202 draws all of its +5V analog power through jumper JU4, which is wired closed when the board is shipped from the factory. To measure the MAX1202’s supply current, modify the board (with the power off) by cutting jumper JU4 and connecting a current meter across JU4. Low-Speed Data Logging The RS-232 serial link limits the data-logging sample rate to no more than 10 samples/sec. The “Log” menu can be used to write data to a user-specified file in comma-spaced-value text format. From the “Log” menu, choose “Select Channels”, and select the channels you want to log. Then choose the “New Log File” command from the “Log” menu. Once a log file has been opened, it can be paused or resumed with the “Pause” command. One complete line of data is written after all enabled channels have been sampled. The first line of the log file contains the column headings. Each subsequent line of the log file contains all enabled channels, separated by commas, tabs, or spaces. The program continues to write data to the log file until the “Done” command is selected from the “Log” menu. High-Speed Data Sampling The high-speed sampling commands can be used for sampling rates over 10 samples/sec. Data can be collected from any single channel at high speed, using the commands on the “Sample” menu. First select the number of samples. Then set the sampling rate either by inserting a delay between samples, or by choosing one of the preset sample rates. Use the “Collect” command to begin collecting data. After the samples are collected, the data is automatically uploaded to the host and graphed. Additionally, the data can be saved to a file. Changing the Reference Voltage The MAX1202 EV kit software assumes a 4.096V reference voltage, unless otherwise specified. The reference-voltage assumption can be changed using “Set Reference Voltage” under the “Device” menu. If an external reference is used, it must have a temperature coefficient of 20ppm/°C or less to achieve accuracy to within four LSBs over the 0°C to +70°C range. For 12bit accuracy over this range, the reference must have a temperature coefficient of 4ppm/°C or less. Detailed Description ________________________of Hardware Components The MAX1202 (U1) is an 8-channel, 12-bit, low-power analog-to-digital converter (ADC) with serial interface and shutdown. R1–R8 and C1–C8 are anti-aliasing input filters. The analog supply rails are VDD, VSS, and GND. The digital interface is powered by the VL pin. The SHDN jumper controls hardware shutdown and selects internal/external-compensation mode. Refer to the MAX1202 data sheet for more information. The ICL7660 (U2) is a charge pump that converts +5V to -5V for VSS. The 78L05 (U3) is a +5V linear regulator that provides a clean analog supply for the MAX1202. Input Filtering The MAX1202 EV kit has an RC filter on each input with a time constant (τ) of approximately 3µs (R = 300Ω, C = 0.01µF). The MAX1202’s acquisition time with a 2MHz clock is 1.5µs. The RC filter’s settling time can increase the acquisition time required for full accuracy when switching input channels. _______________________________________________________________________________________ 3 Evaluates: MAX1202/MAX1203 __Detailed Description of Software +5V 1 R1 300Ω 1 C1 0.01µF R2 300Ω 2 CH1 3 CH2 C3 0.01µF R4 300Ω 4 CH3 C4 0.01µF R5 300Ω 5 CH4 C5 0.01µF R6 300Ω C6 0.01µF R7 300Ω C7 0.01µF R8 300Ω SHDN 3 15 J1-35 VL CH6 14 13 GND REFADJ VSS SHDN REF C13 0.01µF 11 J1-2 REFADJ J1-4 TP-4 TP-5 TP-6 DOUT +3V C10 0.1µF _______________________________________________________________________________________ VREF C9 0.1µF Figure 1. MAX1202 EV Kit Schematic 4 J1-3 TEST POINTS SSTRB -5V J1-1 1 TP-3 2 JU2 GND VREF C12 4.7µF 10V DIN 5 3 J1-8 +5V 10 2 7 VLOGIC 12 TP-2 OSC CAP+ CAP4 J1-29 +5V ICL7660 VOUT GND DOUT 16 CS LV CH5 J1-36 TP-1 3 SSTRB 17 SCLK 6 U2 CH4 J1-31 JU1 8 V+ N.C. DIN 18 JU3 VSS 1 CH3 CH7 9 +5V CS C14 0.1µF C8 0.01µF 2 MAX1202 8 CH7 1 CH2 J1-37 J1-7 7 CH6 J1-6 SCLK U1 6 CH5 C15 0.1µF J1-5 19 CH1 C2 0.01µF R3 300Ω C11 0.1µF VDD CH0 COM 2 TP-8 CH0 JU4 20 U3 +9V TO 78L05 3 +15V OUT IN TP-7 Evaluates: MAX1202/MAX1203 MAX1202 Evaluation Kit MAX1202 Evaluation Kit Evaluates: MAX1202/MAX1203 1.0" Figure 2. MAX1202 EV Kit Component Placement Guide— Top Silkscreen 1.0" 1.0" Figure 3. MAX1202 EV Kit PC Board Layout—Component Side Figure 4. MAX1202 EV Kit PC Board Layout—Solder Side _______________________________________________________________________________________ 5 Evaluates: MAX1202/MAX1203 MAX1202 Evaluation Kit Listing 1. MAX1202 Pseudo-Code Example 6 _______________________________________________________________________________________ MAX1202 Evaluation Kit Evaluates: MAX1202/MAX1203 Listing 2. Bit-Banging Substitute for SPI Port _______________________________________________________________________________________ 7