19-1625; Rev 0; 1/00 MAX1280 Evaluation System Order the complete EV system (MAX1280EVC16) for a comprehensive evaluation of the MAX1280 using a PC. Order the EV kit (MAX1280EVKIT) if the 68HC16MODULE-DIP module has already been purchased with a previous Maxim EV system, or for custom use in other µC-based systems. EV System Component List PART QTY Features ♦ Proven PC Board Layout ♦ Convenient On-Board Test Points ♦ Data-Logging Software ♦ Fully Assembled and Tested Ordering Information PART TEMP. RANGE MAX1280EVKIT 0°C to +70°C User-supplied MAX1280EVC16 0°C to +70°C Windows software Note: The MAX1280 software is designed for use with the complete MAX1280EVC16 EV system (includes 68HC16MODULEDIP module together with MAX1280EVKIT). If the MAX1280 evaluation software will not be used, the MAX1280EVKIT board can be purchased by itself, without the µC. DESCRIPTION MAX1280EVKIT 1 MAX1280 EV kit 68HC16 MODULE-DIP 1 68HC16 µC module EV Kit Component List REFERENCE QTY C1–C8, C10 9 0.01µF ceramic capacitors DESCRIPTION C9 1 4.7µF, 10V tantalum capacitor C11, C13 2 0.1µF ceramic capacitors C12, C14 2 10µF, 10V tantalum capacitors J1 1 2x20 right-angle socket JU1 1 2-pin header JU2 1 3-pin header R1–R8 8 300Ω ±5% resistors R9, R10 2 10Ω ±1% resistors TP1 1 8-pin header U1 1 Maxim MAX1280BCUP (20-pin TSSOP) None 1 PC board, MAX1280 EV kit None 1 3 1/2in software disk, MAX1280 EV kit None 1 MAX1280 EV kit data sheet None 1 MAX1280 data sheet INTERFACE TYPE EV Kit Software Files FILE DESCRIPTION INSTALL.EXE Installs the EV kit files on user’s computer MAX1280.EXE Application program KIT1280.C16 Software loaded into 68HC16 µC Recommended Equipment Before you begin, gather the following equipment: • Maxim MAX1280EVC16 (contains MAX1280EVKIT 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 • A spare serial communications port, preferably a 9-pin plug • A serial cable to connect the computer’s serial port to the 68HC16MODULE-DIP Windows 95/98 is a registered trademark of Microsoft Corp. ________________________________________________________________ Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. Evaluates: MAX1280 General Description The MAX1280 evaluation system (EV system) is a complete, 8-channel data-acquisition system consisting of a MAX1280 evaluation kit (EV kit) and a Maxim 68HC16MODULE-DIP microcontroller (µC) module. The MAX1280 is a high-speed, multichannel, 12-bit dataacquisition system. Windows 95/98® software provides a handy user interface to exercise the MAX1280’s features. Evaluates: MAX1280 MAX1280 Evaluation System Connections and Setup 1) Carefully connect the boards by aligning the 40-pin header of the MAX1280 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. 2) Ensure that JU1 is closed and JU2 is in the 1-2 position. 3) Connect a 7VDC to 20VDC power source to the µC module at the terminal block located next to the on/off switch, along the top edge of the µC module. Observe the polarity marked on the board. 4) 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 will be 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 MAX1280 EV kit 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) Start the MAX1280 program by opening its icon in the Start menu. 7) The program will prompt you to connect the µC module and turn its power on. Slide SW1 to the ON position. Select the correct serial port, and click OK. The program will automatically download KIT1280.C16 to the module. 8) Apply an input signal between analog common (COM) and input channel CH0. Observe the readout on the screen. Detailed Description MAX1280 Stand-Alone EV Kit The MAX1280EVKIT provides a proven PC board layout to evaluate the MAX1280. It must be interfaced to appropriate timing signals for proper operation. Connect +5V to VDD1 and VDD2, and connect the ground return to GND. See the MAX1280 EV kit schematic (Figure 1). Refer to the MAX1280 data sheet for timing requirements. MAX1280 EV System The MAX1280EVC16 EV system operates from a usersupplied 7VDC to 20VDC power supply. Windows 95/98 software running on an IBM PC interfaces to the EV system board through the computer’s serial communications port. See the Recommended Equipment and Connections and Setup sections for setup and operating instructions. Description of Software The evaluation software’s main window controls the active control word bits, serial clock speed, and sample rate. It displays the voltage and output code for each active channel, as well as some statistics of the input signal. A separate graph window shows the data changing in real time. The update rate is limited to about 10 samples per second due to COM port bandwidth limitations. Controls The control word is divided into several fields. To change the active control word, drop down the appropriate field’s combo box and select the desired option. If the QSPI™ clock is set to STOP, then configuration data will not be sent until the READ button is clicked. Statistics The Minimum and Maximum fields show the highest and lowest readings acquired. The Average field shows a running mean based on the equation ai = (k)(xi) + (1 - k)(ai-1). The Clear button resets the statistics. To remove offset errors, first apply 0V to the active input channel, clear statistics, acquire some samples, and then check Tare. This average offset voltage will now be subtracted from all subsequent measurements. Sampling Choose the desired sampling rate (QSPI Clock), sampling size (Sample! menu item), click Begin Sampling! (in Sample! pop-up window). Sample size is restricted to a power of 2 to permit FFT processing once the data is saved to a file. After the samples have been collected, the data is automatically uploaded to the host and is graphed. Once displayed, the data can optionally be saved to a file. Saving Graphs to Disk Data in the real-time graph and in sampled data graphs may be saved to a file. Only the raw output codes are saved, but voltages may be inferred, based on the reference voltage and the maximum code value. Scanning All Channels To scan through all channels, select SCAN from the INPUT menu. QSPI is a trademark of Motorola, Inc. 2 _______________________________________________________________________________________ MAX1280 Evaluation System Reference Voltage The evaluation software assumes a 2.5V reference voltage, unless otherwise specified. Refer to the MAX1280 data sheet for more information. To override this value, type the new reference voltage into the Vref edit box and click the Set Vref button. Description of Hardware U1, the MAX1280, is a high-speed, multichannel, 12-bit data-acquisition system. Resistors R1–R8 and capacitors C1–C8 form single-pole, lowpass anti-aliasing filters with a nominal 3ms time constant and approximately a 50kHz corner frequency. Jumper JU1 connects the analog common (COM) to ground (GND). C10 bypasses the bandgap reference, and C9 bypasses the analog-to-digital converter’s (ADC’s) voltage reference. When plugged into the 68HC16MODULE, VDD1 and VDD2 are both powered by +5V. See the MAX1280 EV kit schematic (Figure 1) and refer to the MAX1280 data sheet. Table 1. Jumper Functions JUMPER JU1 POSITION FUNCTION Closed* COM is connected to GND. COM is disconnected from GND. All analog inputs, including COM, must still be within the MAX1280’s common-mode input range. Open 1-2* Operate 2-3 Shutdown JU2 *Default configuration Troubleshooting Problem: No output measurement. System seems to report zero voltage or fails to make a measurement. 1) Check VDD1 and VDD2 supply voltages. 2) Check the 2.5V reference voltage using a DVM. 3) Verify with an oscilloscope that the conversion-start signal is being strobed. 4) Verify that SHDN is being driven high. Problem: Measurements are erratic, unstable; poor accuracy. 1) Check the reference voltage using a DVM. 2) 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). Measuring Supply Current Power-supply current can be monitored by measuring the voltage across resistor R9 (for VDD1) or R10 (VDD2). These resistors are 10Ω ±1%, so every 0.001V across R9 represents 100µA of supply current. _______________________________________________________________________________________ 3 Evaluates: MAX1280 Evaluating Shutdown The evaluation software configures the 68HC16’s QSPI submodule to continuously read data from the MAX1280 into the 68HC16. The sample rate is controlled by the QSPI clock. To evaluate power-saving modes, these automatic updates must be stopped. First, set the QSPI clock control to STOP. This reconfigures the 68HC16’s QSPI submodule to stop driving the serial clock. Second, in the evaluation software’s main window, uncheck the “Read Every...msec” checkbox. Next, choose the desired software power-down control word, and click the Read button to send the new configuration to the MAX1280. Or, if evaluating the hardware shutdown, move jumper JU2 to the 2-3 position. Sense the supply current by measuring the voltage across resistors R9 and R10. Evaluates: MAX1280 MAX1280 Evaluation System VDD1 J1-7 1 CHO CHO VDD1 20 C1 0.01µF R1 300Ω 2 CH1 CH1 VDD2 3 CH2 CH2 C3 0.01µF R3 300Ω R10 10Ω 1% VDD2 CH4 R5 300Ω C5 0.01µF R6 300Ω C6 0.01µF R7 300Ω C7 0.01µF CS 17 GND TP1-5 DIN 16 J1-1 J1-2 TP1-4 J1-3 J1-4 CH5 SSTRB 15 TP1-3 J1-29 CH6 DOUT 14 TP1-2 J1-35 8 CH7 CH4 J1-36 7 CH6 CH7 GND 13 C8 0.01µF R8 300Ω 9 O COM REFADJ 12 REFADJ C10 0.01µF 1 2 10 SHDN 3 2 1 VDD1 SHDN REF 11 REF C9 4.7µF 10V JU2 Figure 1. MAX1280 EV Kit Schematic 4 J1-8 J1-31 6 CH5 TP1-7 TP1-1 J1-38 5 JU1 C14 10µF 10V TP1-6 C4 0.01µF R4 300Ω C13 0.1µF VDD1 J1-37 MAX1280 CH3 R9 10Ω 1% 18 U1 4 CH3 SCLK C12 10µF 10V 19 C2 0.01µF R2 300Ω C11 0.1µF _______________________________________________________________________________________ MAX1280 Evaluation System Evaluates: MAX1280 Init: LDAA #$08 ; CS high, clock low by default STAA QPDR LDAA #$0F STAA QPAR ; pins that are assigned to the QSPI LDAA #$0E STAA QDDR ; QSM pins that are outputs LDAA #$80 ; CRCONT STAA CR0 ; send eight-bit control word, and continue... STAA CR2 STAA CR4 ... STAA CRE LDAA #$40 ; (CRBITSE) STAA CR1 ; receive sixteen-bit data field STAA CR3 STAA CR5 ... STAA CRF CLRD ; send zero when receiving data STD TR1 STD TR3 STD TR5 ... STD TRF LDAB #%10001111 ; channel 0, unipolar, single-ended, pd=11 std TR0 ; channel 0 command ldab #$40 ; channel 1 bit mask ord TR0 std TR2 ; channel 1 command ldab #$10 ; channel 2 bit mask ord TR0 std TR4 ; channel 2 command ... ldab #$70 ; channel 7 bit mask ord TR0 std TRE ; channel 7 command CLR SPCR3 ; disable QSPI halt mode interrupt LDD #$8008 ; BITS=16, SPBR=8 (1.049 MHz), CPOL=0, CPHA=0 STD SPCR0 LDD #$0204 ; DSCK, DTL not used STD SPCR1 LDD #$4F00 ; newqp=0, endqp=15, wrap to zero STD SPCR2 ; run QSPI continuously on all channels BSETW SPCR1,#$8000 ; start the QSPI BCLR SPSR,#$80 ; clear SPIF bit ReadLoop: LDD RR1 jsr Process_Channel_0 LDD RR3 jsr Process_Channel_1 LDD RR5 jsr Process_Channel_2 ... LDD RRF jsr Process_Channel_7 jmp ReadLoop Example 1. Reading All Channels with QSPI _______________________________________________________________________________________ 5 Evaluates: MAX1280 MAX1280 Evaluation System Init: LDAA #$08 ; CS high, clock low by default STAA QPDR LDAA #$0F STAA QPAR ; pins that are assigned to the QSPI LDAA #$0E STAA QDDR ; QSM pins that are outputs LDAA #$80 ; CRCONT STAA CR0 ; send eight-bit control word, and continue... LDAA #$40 ; (CRBITSE) STAA CR1 ; receive sixteen-bit data field CLRD ; send zero when receiving data STD TR1 LDAB #%10001111 ; channel 0, unipolar, single-ended, pd=11 std TR0 ; channel 0 command CLR SPCR3 ; disable QSPI halt mode interrupt LDD #$8008 ; BITS=16, SPBR=8 (1.049 MHz), CPOL=0, CPHA=0 STD SPCR0 LDD #$0204 ; DSCK, DTL not used STD SPCR1 LDD #$0100 ; newqp=0, endqp=1, no wrap STD SPCR2 ReadLoop: BSETW SPCR1,#$8000 ; start the QSPI BCLR SPSR,#$80 ; clear SPIF bit Idle: BRCLR SPSR,#$80,Idle ; wait util SPIF bit is set LDD RR1 ROLD ROLD ROLD jsr Process_Channel_0 jmp ReadLoop Example 2. Reading a Single Channel with QSPI 6 _______________________________________________________________________________________ MAX1280 Evaluation System Evaluates: MAX1280 1.0" Figure 2. MAX1280 EV Kit Component Placement Guide— Component Side 1.0" 1.0" Figure 3. MAX1280 EV Kit PC Board Layout—Component Side Figure 4. MAX1280 EV Kit PC Board Layout—Solder Side _______________________________________________________________________________________ 7 Evaluates: MAX1280 MAX1280 Evaluation System NOTES 8 _______________________________________________________________________________________ This datasheet has been download from: www.datasheetcatalog.com Datasheets for electronics components.