MAX155 - Part Number Search
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1. cit oa 10 33 p oa i 2 WO ENABLE Figure 1 MAX155 EV Kit Schematic 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 Maxim Integrated Products 120 San Gabriel Drive Sunnyvale CA 94086 408 737 7600 9 2001 Maxim Integrated Products Printed USA MAXIM is a registered trademark of Maxim Integrated Products isajyenjeag SSLXVIN2. for details the uP must toggle the watchdog input once a second to prevent a reset pulse Removing this jumper while the system is running causes a reset For a complete description of the reset and watchdog functions refer to the MAX696 data sheet 80C32 Microcontroller The MAX155 EV kit uses the 80C32 controller The 80C32 is a member of the 8051 family that requires external ROM for program storage Internally it has 256 bytes of RAM and four 8 bit input output I O ports Two of these ports PO and P2 are for operating the address and data lines required by the external ROM RAM and MAX155 A third P3 is needed for the serial link and I O control lines One of the pins of the remain ing port is for the watchdog circuit The others are available for the control of additional user circuits The on board memory consists of 8kB of EPROM the 27C64 holding the instructions for normal operations and 8kB of CMOS RAM the 6264 to store conversion results The user initiates a conversion at the keyboard of a per sonal computer running the MAX155 EV program The program sends an encoded conversion command over the RS 232 link to the board The 80C32 receives the command performs the MAX155 conversion and returns the results for display Address Decoding The 80C32 has a 16 bit address range 0000h to FFFFh The data bits on the 80C32 pins 32 39 multi plex the lower eight address bits The 74CT573 latches the address bits a
3. lines to ADC devices should avoid the current spikes found on supply lines to digital circuits Software Architecture The software driver for the MAX155 EV kit is divided into two elements One is the ROM code written for the 80C32 controller The other is a program written in C that runs on an IBM compatible personal computer The disk supplied with the kit contains the instruction manuals and source code for each program The disk also holds two other important files The first is a README file describing any changes to the hardware or software Be sure to read the file as soon as possi ble The other file is an update registration form Be sure to fill out and return the update form for future package updates ROM Firmware The 80C32 code was written using the AVOCET 8051 Assembler The output code is stored in a 27C64 EPROM placed on the MAX155 EV kit board The EPROM code initializes the 80C32 after a reset and establishes communications over the RS 232 serial link After reset the program continuously transmits an A5 hex character until the proper response is received It then waits for the command for a conver sion or other function The list of available commands is in the disk documentation Personal Computer Software The MAX155EV exe program runs on an IBM compatible computer It displays the EV kit status and conversion results The program establishes the communications link with the EV kit board The status flag in the lo
4. seats a 6264 ICO wipe ole tds eases 74HCT245 IGT Oo ei cea nate a MAX155 IGA Vs pe ke BAe eases MAX660 GA 23 Pee cain ems amp 74HCT161 GAS 23s Sr ates a eps 10MHz Oscillator ICTA oe ces cece oN MAX667 When assembly is complete carefully examine the board for possible solder shorts and misinserted parts Verify that all ICs are in their proper position and not reversed Verify that all tantalum capacitors are insert ed with their positive pin aligned with the sign on the board Verify that D1 is not reversed Setup Instructions Attaching the Terminal The MAX155 evaluation board connects to one of the two possible serial ports COM1 or COM2 commonly found on an IBM compatible personal computer The user must determine and supply the type of cable needed to make the connection The connector for these ports can be a D9 9 pin or D25 25 pin con nector The connector on the EV kit is a D9 connector Consult the computer user manual for the information regarding the location and type of the serial communi cations connector s available on your system If the computer has a D9 connector available a stan dard straight through cable can be used If the only available COM port connector is a D25 an adapter is required The necessary adapter is commonly used with other serial operated devices and is readily avail able at computer supply stores The RS 232 protocol defines the function of each con nector pin It r
5. the watchdog function resets the uP if it fails to toggle the watchdog input once every second A shunt is normally installed across the jumper pins to enable the watchdog It can be removed before power up to avoid unwanted resets while debugging 80C32 software See the MAX696 data sheet for more information Clock Selection A 74HCT161 binary counter divides the 10MHz clock signal This device s four outputs are selectable with J10 J13 The boards are built with a trace across J10 MAAKLM to get the 5MHz signal 10MHz divided by 2 Other ratios can be used by cutting J10 and installing a jumper across one of the other options J11 J12 J13 Negative Supply Voltage J4 and J5 select the MAX155 Vss voltage The trace across J4 connects the 5V output of the MAX660 to the MAX155 s Vss pin This configuration is required for the bipolar input range If J4 is opened and J5 shorted Vss is connected to ground When Vss is grounded the inputs to the MAX155 should not be pulled below OV External Reference J6 connects the MAX155 internal 2 5V reference to the reference input pin An external 2 5V reference can be used by cutting the trace across J6 and connecting the external source to the pad marked VREF IN MAX155 Mode Selection J7 and J8 are connected to the MAX155 MODE pin Software selects the input range it both J7 and J8 are left open If fixed input ranges are desired the appro priate jumper can be installed Table 3 Ju
6. 19 0012 Rev 1 1 01 General Description The MAX155 evaluation kit EV kit is a functional 8 channel 8 bit data acquisition system The printed cir cuit board has an 80C32 microprocessor controlling the MAX155 analog to digital converter Software run on an IBM compatible personal computer communicates over an RS 232 link to perform analog to digital conversions and display the results The input channels can be configured in a variety of combinations of single ended differential and unipolar bipolar modes All input channels are sampled simultaneously at the beginning of each conversion for low skew between channels A single channel can be selected for conversion and display or all channels can be read The board operates from a single 6V to 12V supply A MAX660 generates the 5V supply needed for converting voltages below ground Features Fully Functional 8 Channel 8 Bit DAS Eight Simultaneously Sampling Track Hold Inputs 0 to 2 5V Unipolar or 2 5V Bipolar Input Range Single Ended or Differential Inputs Mixed Input Configurations are Possible 2 5V Reference Voltage EV Kit Operates from a Single Input Supply gt gt gt gt o gt o Software for IBM Compatible Computers Included MAAKI MAX155 Evaluation Kit Ordering Information PART TEMP RANGE BOARD TYPE MAX155EVKIT 0 C to 70 C Plastic DIP Through Hole EV Kit Functional Diagram MAXIM c MAX233 waTC
7. Analog Section This section assumes that the board communicates correctly with the host computer However the read ings displayed by the MAX155 program do not corre late to the input voltages 5V Power Supply Use a DVM to read the MAX155 Vss voltage on pin 6 If the voltage is not more negative than 4 5V the prob lem is the MAX660 J4 has been cut or the MAX155 is defective J4 can be cut to see if the MAX660 output returns to 5V Conversion Problems If the 5V is correct and readings are erroneous check the following Make sure the reference input voltage on pin 22 is between 2 45V and 2 55V If not and J6 is intact the MAX155 is at fault Make sure the input voltage is correct Use a DVM to measure the input voltage while doing conversions The reading agrees within 8 bits resolution as long as the input voltage level is 0 to 2 5V If not the MAX155 or the 74HCT245 is at fault MAALM MAX155 Evaluation Kit ENLARGE VIEW N pF UNLESS mcns i 46 ADC CLOCK SELECT 2 c20 21 oa o C19 on C18 oa 7 on C16 on cu on cr cw at fot toto tt
8. HNG 2 ENABLE e lt DRESS BUS gt gt MAXIM INPUTS MAX155 MAXIM 4000H 7FFFH MAXIM MAX696 MAX660 COQQH CFFFH MAXIM Vin gt 6V TO 12V MAX696 MAXIM Maxim Integrated Products 1 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 isajyenjeag SSLXVIN MAX155 Evaluates MAX155 Evaluation Kit Component List DESIGNATION QTY DESCRIPTION None A 8 0in x 5 5in MAX155 EV kit printed circuit board 1 MAX233ACPP 1 IC1 IC3 80032 IC4 74HCT573 IC5 74HCT08 74HCT139 27C64 6264LP 74HCT245 MAX155BCPI MAX660 10MHz OSC MAX667CPA CTS CTX078 11 059MHz crystal 2 pin header and shunts J1 J2 Connector 1 2 wire power connector Connector 2 D9 right angle female connector 13 0kQ 1 resistor 10kQ 5 resistor 1 0kQ 5 resistors 27pF capacitors C1 C2 C3 C6 C9 C11 012 C13 C14 C16 C17 C18 C19 C20 C21 C4 C5 C7 C8 10uF 16V tantalum C15 capacitors 33yF 16V tantalum capacitors 10 pin 9 resistor 10kQ SIP 28 pin IC sockets for EPROM and MAX155 0 1uF 50V monolithic capacitors C10 C22 Quick Reference Setup and operation of
9. be capable of 150mA The input supply passes through D1 and is regulated to 5 0V by the MAX667 The current available for additional user circuits in the prototype area is limited by the capabilities of the MAX667 Refer to the MAX667 data sheet for detailed information before connecting loads greater than 20mA The MAX155 Vss pin can be connected to ground in many applications The 5V supply is necessary only when the system requires inputs below ground bipolar single ended mode with 2 5V input range The EV kit includes a MAX660 to generate the 5V needed to enable this feature Additional circuits can draw power from this source as long as the load is no more than 10mA For more current the 10uF capacitors around MAXIN the MAX660 must be increased to 150uF Refer to the MAX660 data sheet for more information Microprocessor Supervision A MAX696 is used to generate the reset pulse and for the watchdog function The microprocessor uP is held in reset for 50ms after the voltage on the low line input LLIN exceeds its threshold The values of R1 and R2 are selected so that a 4 25V supply voltage 0 24V trips the LLIN comparator The watchdog monitoring function issues a reset pulse if the watchdog input is not toggled within the specified period of time By leaving the MAX696 OSC IN and OSC SEL pins disconnected the MAX696 watchdog period is set to 1s If the watchdog enable jumper is installed see the Jumper Options section
10. edance allows this precaution without introducing additional errors There are two input ranges for the MAX155 Either the unipolar 0 to 2 5V or bipolar 2 5V to 2 5V range can be selected under program control It is possible to hardwire the range selection for other applications In bipolar differential mode the readings reflect the voltage between the two analog inputs For example if the ViN pin is referenced to 2 5V input range is 0 to 5 0V The output readings 2 50V to 2 49V indicate the differential voltage between ViN and ViN This allows bipolar differential operation with single supplies See the MAX155 data sheet for details Maxim took several precautions to reduce the system s noise level Users should consider noise reduction as part of their design The data bus to the MAX155 is buffered by IC9 a 74HCT245 octal transceiver This device isolates the MAX155 from the digital signals constantly present on the data bus This reduces the noise level of any ana log to digital converter ADC in a digital environment 3 isayenjeag SSLXVIN MAX155 Evaluates MAX155 Evaluation Kit However an 8 bit device like the MAX155 does not require data bus isolation in many applications Precautions were also taken to avoid digital noise in the ground and 5V supply lines to the MAX155 On the board layout both traces to the MAX155 are wide traces that return directly to the regulator output In general supply
11. equires that the equipment on one end of a cable function as data terminal equipment DTE and the other as data communications equipment DCE The personal computer PC end is the DTE and the MAX155 EV kit is connected as DCE Table 4 Serial Communication Cable Pin Functions D9 to D9 connection use straight through cable COMPUTER D9 CONNECTOR MAX155 EV KIT D9 RS 232 DTE CONNECTOR DCD 1 1 RxD 2 2 TxD TxD 3 3 RxD DTR 4 4 GND 5 5 GND DSR 6 6 RTS 7 7 CTS 8 8 RI 9 9 N C D25 to D9 connection adapter required COMPUTER D25 CONNECTOR MAX155 EV KIT D9 RS 232 DTE CONNECTOR DCD 8 1 RxD 3 2 TxD TxD 2 3 RxD DTR 20 4 GND 7 5 GND DSR 6 6 RTS 4 7 CTS 5 8 RI 22 9 N C Loading the Software Before doing anything else make a copy of the disk provided with the MAX155 EV kit Use the copy for all operations and keep the original in a safe place If a hard disk is available all files can be copied to a direc tory and executed from there If the files are to be accessed from a floppy drive select the drive for default operation For example enter A to use drive A If the files have been copied to a hard disk set the default directory to the one holding the MAX155 files The disk contains a README file that lists any changes to the hardware or software Read the README file before proceeding The MAX155 EV Kit Users Manual which covers the operation of the p
12. mper Selected Hardwired Modes CONVERSION TYPE MODE Vss JUMPER JUMPER Software controlled multiplexer mode default mode Software controlled SE or differential mode unipolar or bipolar mode all analog inputs above ground 4 channel differential bipolar mode 4 channel differential unipolar mode 8 channel single ended bipolar mode 8 channel single ended bipolar mode MAKINI MAX155 Evaluation Kit The MAX155 EV software cannot read the state of jumpers J4 J8 The program must be manually config ured to agree with the hardwired mode if the jumpers differ from the default condition Board Assembly The MAX155 EV kit board is shipped unassembled The only assembly tools needed are a standard solder ing iron with a grounded tip and wire cutters Assembly takes about an hour The builder must have basic elec tronic skills such as soldering and the ability to deter mine component values Remove the board and parts from the box and perform the following steps 1 Verify that all parts on the component list are present 2 Mount and solder the D9 and power connectors onto the board 3 Solder all resistors in place and trim their leads RI A aa an fe EAR teat 32 4kQ 1 OSs i a e Bet E a 13 0kQ 1 FAS a Geta T boned Het 10kQ 5 R4 RAlt ow ee ee eee 1kQ 5 4 Solder all capacitors in place and trim their leads Observe the polarity of the tantalum capacitors In sert the positi
13. nd ROM and RAM use them as AO A7 The upper eight bits of the address field are not multiplexed Six of these bits A8 A13 are sent directly to the memory address pins MAXIM MAX155 Evaluation Kit The two most significant bits of the address are decod ed and used to selectively enable ROM RAM or the MAX155 The next two bits of the address field A13 and A12 are also used in decoding the address range for the MAX155 The MAX155 is accessed whenever a location between C000h and CFFFh is addressed Table 1 shows the address range for each device Table 1 Address Range in Hexadecimal A14 A15 ADDRESS RANGE DEVICE ENABLED 00 0000 gt 3FFF ROM RAM 4000 7FFF 8000 BFFF C000 gt CFFF D000 gt FFFF Not used MAX155 Not used MAX155 The MAX155 on the EV kit is configured to use its internal reference and to allow a bipolar input range The MAX155 internal reference can be replaced by cutting the trace across J6 and providing an external reference voltage The bipolar input range is facilitated by a 5V source con nected to Vss pin 6 The MAX155 MODE selection pin is open circuited to place the input range selection under program control See the Jumper Selection section for details regarding the MODE selection pin The eight analog inputs are available at the board s edge Each input has a 1kQ resistor in series as protec tion against excessive short circuit currents The high input imp
14. rogram is also on the disk MAX155EV doc If a printer is available print MAAKLM both files by entering PRINT README and PRINT MAX155EV doc Either file can also be examined or printed using a word processing program After reading the MAX155EV doc file type MAX155EV to start the program Set the program to the port to which the board is connected COM1 or COM2 With the board connected turn on the board power The program displays the status of the communications link between the system and the board If the status does not indicate READY see the Troubleshooting Guide section Many different input configurations are possible for the MAX155 s analog inputs Consult the MAX155 data sheet for full details Apply the input levels to the eight inputs and use the software to configure the input multiplexer as desired Enter a number 0 7 to select an input then enter the command for the proper mode Read the MAX155EV doc file for full information about program commands Table 2 lists the available com mands Troubleshooting Guide The following is a checklist to help isolate problems on the MAX155 EV kit board It is recommended that each step be done in the order given Do not proceed until each fault has been corrected If the MAX155 EV pro gram indicates that the board status is READY but the conversions are erroneous go to the following Analog Section Digital Section Power Is the 5V okay Check the MAX667 ou
15. t 10V Every 280ms a stream of bits lasting 3ms is transmitted The voltage swings from 10V to 10V If okay go to the next step If the output is stuck at 10V or 10V check the input of the MAX233 pin 2 If it is an inverted 0 to 5V copy of the above the MAX233 is okay and the ROM or the 80C32 is at fault If all of the above are operating correctly the next step is to verify the connection to the PC The MAX155 EV program can be placed in an echo mode of sending characters typed on the keyboard and displaying those received from the COM port Make sure the cable is connected to the proper serial port and to the board Start the MAX155 EV program and type Q Ctrl Q to set echo mode Each character typed on the keyboard should now be displayed on the screen If not perform the following checks Does pin 5 of the MAX233 swing greater than 5V to 5V whenever a character is entered If not the correct port is not selected or present Try again with the other port isajyenjeag SSLXVIN MAX155 Evaluates MAX155 Evaluation Kit Is pin 2 of the MAX233 an inverted 0 to 5V copy of the signal on pin 5 If not the MAX233 is faulty Is pin 3 of the MAX233 an inverted 0 to 5V copy of the signal on pin 5 If so the ROM or other parts of the board are at fault If pin 3 is okay check pin 4 Is it a 10V to 10V inverted copy of the signal on pin 5 If not the cable the PC port or the MAX233 could be at fault
16. the MAX155 EV kit involves the following steps 1 Assemble the printed circuit board using the proce dure in the Board Assembly section 2 Copy the MAX155 EV kit floppy disk to another disk and store the original in a safe place Use the copy for normal operation 3 Read the README file for updates and changes 4 Connect a cable between a serial port COM1 or COM2 of the personal computer and the MAX155 EV kit printed circuit board If a 9 pin D9 connec tor is available a straight through cable can be used If the only available connector is a 25 pin D25 connector an adapter is required 5 Start the MAX155 EV software program on the personal computer and set the indicated active port to agree with the cable location The status line at the bottom of the display shows the COM port and board status 6 Apply power to the printed circuit board and make sure the board status display in the lower right corner indicates READY If not see the Trouble shooting Guide section 7 Connect the input signals to the analog input s and the system is ready for operation Detailed Description Hardware Architecture The following is an overview of the various circuits found on the MAX155 EV kit printed circuit board Refer to the individual device data sheets for complete descriptions Power Supply The MAX155 EV kit requires a 6V to 12V input supply The board typically draws 80mA of current however the input supply should
17. tput Is the voltage on pin 2 between 4 8V and 5 2V Go to next section if okay Is the input voltage pin 8 between 5 5V and 11 5V If yes the MAX667 may be damaged Make sure all components are inserted correctly and no shorts exist If not input source is not connected or not functioning D1 could also be installed incorrectly Microprocessor Does the reset operate correctly The RESET line pin 16 of the MAX696 should be high for 50ms after power up or whenever J1 is momentarily shorted then go low If not make sure J1 is open and the MAX696 is correctly installed and undamaged MAKINI MAX155 Evaluation Kit Is the 80C32 s clock running Use a scope to check pin 19 of the 80C32 The 11 059MHz should appear distorted but present If not the crystal or the 80C32 might be damaged Does the 80C32 access the ROM Use the scope to check pin 40 of the 80C32 the AO DO signal It this signal does not toggle every microsecond one of the following devices may be at fault IC3 80C32 controller IC4 74HCT573 address latch IC5 74HCT08 part of address decode IC6 74HCT139_ part of address decode IC7 27064 ROM IC8 6264 RAM IC9 74HCT245_ data bus buffer IC8 AND IC9 CAN BE REMOVED FOR DEBUG GING Terminal Connection Does the board transmit a stream of A5 hex characters after a reset Disconnect the cable to the PC and reset board Then use a scope to look at pin 2 of the D9 connector Normally the output is a
18. ve pin into the pad with the adjacent ol sign C1 C2 nctaci anes Siete es 27pF C3 C6 C9 C11 C12 C13 C14 C16 C17 C18 C19 C20 C21 0 1uF C4 C5 C7 C8 Cio eaa A aa 10uF TANTALUM C10 C22 DP aA 33uF TANTALUM 5 Solder the 10kQ 10 lead SIP RSIP1 into place Polarity is marked on the board by the rounded end of the legend Match this end with the marked end of the SIP usually marked with a dot or a notch 6 Solder the 11 059MHz crystal in position 7 Solder D1 the 1N4001 diode in place Align the polarity bands on the diode and printed circuit board 8 Solder the 28 pin IC socket in the position marked IC7 27C64 and IC10 MAX155 All other ICs may be socketed if desired 9 Solder a jumper set in J1 MANUAL RESET and J2 WDI ENABLE Place the first shunt across the J2 jumper Place the second shunt on one pin of J1 leaving J1 open isayenjeag SSLXVIN MAX155 Evaluates MAX155 Evaluation Kit 10 Install each IC and solder in place if not in sockets Examine each device after soldering to ensure there are no solder bridges shorting between pins Proper ESD prevention techniques should be fol lowed when handling any of the semiconductors IGA Beit pce heat tees MAX233 G2 res coe ai a neem a MAX696 Ors eee eee eae aoe 80C32 Ee ai a ces teenage ee fees 74HCT573 IGOR Aas e E A AET 74HCT08 IGG Sein ei cette as a 74HCT139 ICZ Ae aE hee aoe 27C64 socketed CBee ce tetanic
19. wer right corner of the screen indicates READY when com munication has been established A menu of available commands appears at the bottom of the screen during operation For a detailed explana tion of the commands read the SOFTWARE doc file found on the disk For information on program installation see the section titled Loading the Software Table 2 MAX155 EV Software Command List 0 7 Select a channel Set single ended mode S D Set differential mode U Set unipolar mode B H R Set bipolar mode Set hexadecimal output format Collect sample and save in RAM Examine the RAM contents Continuous conversion Single conversion Application Information Power Requirements The typical EV kit board consumes 80mA from a 6V to 12V external power supply The supply can be an adjustable laboratory supply a 9V alkaline battery or an isolated wall mounted DC power supply Jumper Options Manual Reset J1 on the printed circuit board is the MANUAL RESET jumper These pins are connected to the MAX696 s LLIN input and ground If the LLIN input is lower than 1 30V a reset pulse is generated To manually reset the board briefly place a short across the pins and remove After reset the board attempts to establish communications with the host system These pins should never be connected to other parts of the circuit Watchdog Enable J2 is the watchdog enable jumper WDI ENABLE If enabled
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