DSTO-TR-1215 PR
Contents
1. Ihe Lee Dies E E E En 10 3 2 1 2 Read the Initialisation Bleu 11 33 YO Bus Address Decoding uesussssnssnsnssssnsnnsnssnsnsnnnnsnnsnssnsnsnnsnnsnsnsnunnnsnnnns 11 3 4 PXB 721 Board Configura OM iii 12 3 5 PC 74LA Board Configuration inicia iii 12 39 1 BE 74 ER Register SEIT Oe ans 12 2 9 2 AUSSER ee tan 13 393 ADCSR 13 3 5 4 ADDAT DADATO Low Bytes una 13 3 5 5 ADDAT DADTO High Bytes ae es 14 3 30 DADA alos 14 207 IMRETR nata aos bs 14 4 REFERENCES ansehe 14 Contents 5 ACENOWLEDGEMEN 14 DSTO TR 1215 1 Introduction The Auxiliary Data Module ADM provides a suite of interface facilities which provide access to data for non standard external monitoring or processing equipment for the Low Speed Wind Tunnel LSWT at the Aeronautical and Maritime Research Laboratory AMRL The suite includes two digital input ports two digital output ports eight analog input ports two analog output ports two standard serial communication ports and two additional digital input ports dedicated to tachometer data available from wind tunnel models with powered propellers The digital ports are provided by two identical re configurable commercial plug in boards The analog ports are provided by a further commercial plug in board The serial ports are the COM 12. and COM 2 ports of the IBM PC platform which is used as a basis for the module The ADM operating software consists of C version 3 1 modules with the support of the multi tasking program Real Time Kernel RTK version 4 5 2 Module hardware The ADM is based on a standard IBM PC chassis which has been modified to be contained within VME physical module size standards Figure 1 shows the module installation The usual PC power ON OFF switching is retained but concealed behind a VME standard panel Mains power is routed via the module s cooling fan tray which contains the main accessable power switch for the module This is the normal arrangement for the LSWT data acquisition system The interface functions are carried out by commercial plug in boards Digital I O uses two identical configurable PXB 721 interface boards The analog functions use a single PC 74LA analog interface board Serial communication is conducted using the PC Com ports COM1 COM2 A 3COM Etherlink3 ethernet adapter board is used to interface the module to the LSWT ethernet providing accessibility for the master computer User interface connections are made on the Auxiliary Interface connector field mounted on a panel at the rear of the VME rack system Extension cabling connects the panel connectors to the respective interface plug in boards within the ADM Figure 2 shows the user connector panel with basic functional explanations Figure 3 shows the appearanc
3. as 8 differential channels or 16 single ended channels 2 5 V 5 V bipolar input range or a0 to 5 V unipolar input range The default selections are 8 Differential channels with a 5 V analog I O range Conversion is continuous and the program uses polled operation The conversion rate is set by the PC 74 timer software setting 2 2 3 Analog Input Circuit The PC 74LA board is configured for 8 differential analog channels The board must have a ground reference which is provided through a resistor of value 7 5 K from the outer line of the insulated coaxial BNC connector to the board s analog ground This ground is extended from the PC 74LA board I O header connector to the connector panel by the ribbon extender cables from within the ADM module The circuit arrangement is shown in Figure 5 DSTO TR 1215 8 Channel Connecting Panel Analog Inputs Multiplexer Programmable Gain Amplifier Ch 2 to Ch 6 Figure 5 Ground Reference Circuit for the Analog Input Function 2 2 4 Analog Output Sub system Two Digital to Analog Conversion DAC ICs provide the two channels of analog output with 12 bit resolution The output range is hardware selectable Selections available are 5V 2 5 and 0 to 5V The bipolar 5V option is selected as the default value The linearity of this sub system is nominally 0 01 FSR The Analog output channels are available at two insulated BNC coaxial sockets on the connector panel marked a
4. is a Senior Officer Technical Grade C who has qualifications equivalent to Certificate of Technology He has worked in AMRL for 15 years and for Air Operations Division for the last 5 years He has extensive experience in Data Acquisition in the wind tunnel and Navy helicopter and ship trial environments He has more recently been involved in human factor research in helicopter night operations 1 INTRODUCTION siii 1 2 MODULE HARDWARE na 1 21 721 Digital Interface Board nenne 3 2 1 1 Digital Interface Connection a 4 2 1 2 Digital Interface Panel Connector Pin 8 2 0244222 2 4 2 1 3 Tachometer Input Interface aan 4 2 1 4 Digital Port Connector Alo HO ans 5 2 2 PC 74LA Analog Interface Boat diccionario iii 5 2 2 1 PC 74LA Board Configuration System ae 5 2 2 2 Analog Input Subssystem ak Rn 6 2209 Analog Input ae 6 22 4 Analog Output Subsysten un WER a 7 2 3 Network Interface Card NIC 000002000000000200200n00n200200000nn0nnnnansnnennenansansnnennene 7 3 MODULE SOFTWARE else 7 3 1 ADM Software Initialisation na 8 31 1 3C5X9PD Packet Driver pr as 8 3 1 2 Date and Time Synchronisation till tra 8 3 1 3 Downloading an Initialisation Heuss ser 9 3 2 ADM General Operation indi dos 9 3 2 1 Initialisation of the AUXILARY program 9
5. refers to these as IC1 to 3 on Board 1 and IC4 to 6 on Board 2 Each 8255 IC has three 8 bit ports referred to as amp The module accesses and a B port to make a 16 bit port on each of IC1 2 3 amp 4 to form the two 16 bit input digital ports and the two 16 bit output digital ports 5 amp IC6 are used to provide the tachometer input ports Port A of IC5 and Port A of IC6 are used to provide Tachometer 1 and Tachometer 2 inputs respectively IC port setting up is done by the ADM software Data bytes are written to the IC configuration register Details of this are described in Section 3 4 For simplicity polled operation is used to access all the ports The user of Auxiliary Module digital I O will refer to these ports simply as Digital Input 1 and 2 Digital Output 1 and 2 or Tachometer 1 and 2 1 Intel Microprocessor and Peripheral Handbook Vol II 1989 DSTO TR 1215 2 1 1 Digital Interface Connection The Digital I O ports on the connector panel are 37 pin D37 male connectors Female D37 plugs are required to use these ports The panel sockets are cabled directly to the 8255 header sockets on the daughter boards of each PXB 721 board To avoid damage to the IC devices due to exceeding absolute voltage and current limits for the 8255 chips the following limits apply Absolute Maximum Voltage 0 5 to 7 Volts wrt ground Output Drive Current 4 mA this infers a minimum load of 750 ohms The interface is no
6. release OVERSEAS ENQUIRIES OUTSIDE STATED LIMITATIONS SHOULD BE REFERRED THROUGH DOCUMENT EXCHANGE PO BOX 1500 SALISBURY SA 5108 16 DELIBERATE ANNOUNCEMENT No Limitations 17 CASUAL ANNOUNCEMENT 18 DEFTEST DESCRIPTORS Wind tunnel tests Aerodynamics Data Acquisition Low speed wind tunnels Modules 19 ABSTRACT An IBM PC based electronic module is described which extends the capability of the data acquisition system of the Low Speed Wind Tunnel LSWT at the Aeronautical and Maritime Research Laboratory AMRL Occasions arise when wind tunnel measurements require external data input or specific data extraction by external or temporarily acquired equipment Access to the data is provided by the Auxiliary Data Module ADM The ADM is one of the VME modules in the LSWT instrumentation console The functions of two types of plug in commercial board are used to provide a suite of digital input and output functions using a total of three boards Two input two output and two tachometer channels are provided by two identical I O boards in addition to the two standard PC RS 232C serial communication ports The second plug in board type provides eight analog input channels and two analog output channels with 12 bit resolution Page classification UNCLASSIFIED
7. 2 which form part of the ADM operating software The tachometer signals are cabled to the connector panel from the model in the test section of the wind tunnel and appear on two additional D37 sockets These signals are linked to the digital I O input connectors 5 and 6 of the panel using external ribbon link cables on the external face of the connector panel which is shown in Figure 3 2 1 4 Digital Port Connector Allocation The panel connectors allocated to the Digital I O Ports are listed in Table 2 Table 2 Allocation of Digital Input Output Ports Digital Port Connector D37 Digital In 1 Digital In 2 Digital Out 1 Digital Out 2 Tachometer 1 Tachometer 2 2 2 PC 74LA Analog Interface Board 2 2 1 PC 74LA Board Configuration System Configuration of this system board is achieved partly by hardware link positions and by software commands which place specific values into board registers Figure 4 shows the PC74LA plug in board DSTO TR 1215 Figure 4 The PC74LA Analog Interface plug in board 2 2 2 Analog Input Sub system The Analog to Digital Converter ADC subsystem consists of a monolithic Integrated Circuit IC capable of providing 12 bit conversion for 16 multiplexed channels An instrumentation amplifier with software selectable gain values of 1 10 100 500 isolates the input of the ADC The ADM program sets the pre amplifier gain to 1 as a default value Physical links select input characteristics such
8. Abstracts Reference Service Engineering Societies Library US Materials Information Cambridge Scientific Abstracts US Documents Librarian The Center for Research Libraries US INFORMATION EXCHANGE AGREEMENT PARTNERS Acquisitions Unit Science Reference and Information Service UK Library Exchange Desk National Institute of Standards and Technology US National Aerospace Laboratory Japan National Aerospace Laboratory Netherlands SPARES 5 copies Total number of copies 64 Page classification UNCLASSIFIED DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION DOCUMENT 2 TITLE 3 SECURITY CLASSIFICATION FOR UNCLASSIFIED REPORTS THAT ARE LIMITED RELEASE USE L NEXT TO DOCUMENT An Auxiliary Interface Instrumentation Module for the AMRL CLASSIFICATION Low Speed Wind Tunnel Data Acquisition System Document U Title U Abstract U 4 AUTHOR S 5 CORPORATE AUTHOR F J Bird Aeronautical and Maritime Research Laboratory 506 Lorimer St Fishermans Bend Victoria 3207 Australia 6a DSTO NUMBER 6b AR NUMBER 6c TYPE OF REPORT 7 DOCUMENT DATE DSTO TR 1215 AR 012 026 Technical Report October 2001 8 FILE NUMBER 9 TASK NUMBER 10 TASK SPONSOR 11 NO OF PAGES 12 NO OF M1 9 743 RDI 98 179 DSTO 13 REFERENCES 13 URL on the World Wide 14 RELEASE AUTHORITY http www dsto defence gov au corporate reports DSTO TR 1215 pdf Chief Air Operations Division 15 SECONDARY RELEASE STATEMENT OF THIS DOCUMENT Approved for public
9. An Auxiliary Interface Instrumentation Module for the AMRL Low Speed Wind Tunnel Data Acquisition System F J Bird Air Operations Division Aeronautical and Maritime Research Laboratory DSTO TR 1215 ABSTRACT An IBM PC based electronic module is described which extends the capability of the data acquisition system of the Low Speed Wind Tunnel LSWT at the Aeronautical and Maritime Research Laboratory AMRL Occasions arise when wind tunnel measurements require external data input or specific data extraction by external or temporarily acquired equipment Access to the data is provided by the Auxiliary Data Module ADM The ADM is one of the VME modules in the LSWT instrumentation console The functions of two types of plug in commercial board are used to provide a suite of digital input and output functions using a total of three boards Two input two output and two tachometer channels are provided by two identical I O boards in addition to the two standard PC RS 232C serial communication ports The second plug in board type provides eight analog input channels and two analog output channels with 12 bit resolution RELEASE LIMITATION Approved for public release DEPARTMENT OF DEFENCE DEFENCE SCIENCE amp TECHNOLOGY ORGANISATION DSTO Published by DSTO Aeronautical and Maritime Research Laboratory 506 Lorimer St Fishermans Bend Victoria 3207 Australia Telephone 03 9626 7000 Fax 03 9626 7999 O Commonwea
10. IOP1 DIOP2 This port is unused TMRCTR Clock Frequency select 0 1 2 3 4 5 6 7 3 5 2 ADGCR The lower four bits of this register hold the required channel in binary form Bits 6 and 7 hold the code for the gain required Unity gain is set as default Bits 4 and 5 are not used 3 5 3 ADCSR The Mode 0 is always the operation mode no interrupt or DMA is required The register is read to determine the status of the ADC and if data is available A write action is required to clear bit 4 if a conversion error occurs The content of the ADCSR register is described in Table 7 Table 7 Content of the ADCSR Register Bit Description Bit 0 of Mode Selection set as 0 Bit 1 of Mode Selection set as 0 Interrupt Enable Bit set as 0 DMA Enable Bit set as 0 A D Error Clear Bit write 1 to clear A D Busy Flag during conversion Set on Conversion Error Set on Conversion Completion ND OF 3 5 4 ADDAT DADATO Low Bytes This register has a dual function During ADC operation it contains the low byte of the conversion result During DAT operation it contains the low byte of the input data word to be loaded into DACO 13 DSTO TR 1215 14 3 5 5 ADDAT DADTO High Bytes This has the same functioning as ADDAT DADATO except that the high byte of the data is used A read operation at the end of an ADC conversion clears the conversion completed condition of bit 7 of ADCSR A DAC conversion is initiat
11. When the AUXILARY program is started it immediately opens a file Any error messages are written to the file as well as to the screen Since error messages on the screen are only there for a short time the file is amore permanent record of a problem or other notable aspects of the ADM operation The filename is made up from the current date and time that the file is opened Since date and time cannot be easily placed in a name limited to eight characters the fields are encoded The first three letters are taken from the name of the instrumentation module so log files from different modules can be archived in acommon directory In this case the first three letters will be AUX The next letter of the file name represents the month This is encoded in hexadecimal ie base 16 so that January is O zero and December is represented as B Letter number five in the file name is an encoded representation of the day in the month The first day of the month is denoted by 1 and day 31 by V Effectively this is encoding to base 32 with an offset of 1 Letter number six in the filename is a base 24 encoding of the hour of the day The hour just after midnight is represented as 0 zero and the hour just before midnight hour 23 as the letter N Letter number 7 and letter number 8 are grouped together to show the minute when the file was created This is not encoded Minute zero is represented as 00 and minute 59 as 59 The extension for the filename is set to LOG t
12. ands enable it to log into the master computer change to the net ini directory and download the AUXILARY INI file which becomes the latest AUXILARY INI on the ADM disk The contents of the AUXILARY INI file are dealt with later in Section 3 2 on the main ADM program 3 2 ADM General Operation Once the initialisation phase of the AUTOEXEC BAT file has been done general operation of the ADM is controlled by the AUXILARY EXE program This program also provides the data in the database to any computer on the network that requests it Two methods of making the data available to computers external to the ADM are possible A direct request for an item of data from the database is the first method The second method is known as streaming mode Once the ADM is told to operate in streaming mode it repeatedly broadcasts packets on the network containing all of the parameter data in the local database Any computer on the network can listen to the broadcast data and make immediate use of it 3 2 1 Initialisation of the AUXILARY program The initialisation process consists of recording any error messages in a log file and using data stored in an information file setting up IP addresses for accessing by the master computer and other modules The initialisation process described in the following paragraphs is depicted in Figure 6 DSTO TR 1215 10 Figure 6 Initialisation Sequence of the AUXILARY program 3 2 1 1 The Log File
13. ctor words from the host passing these on to DB_HNDER C for processing to form the index for host database access 3 1 ADM Software Initialisation The ADM operates in the following way After the power is turned on or after reset 1 The module being a PC goes through all the normal power on self testing and then loads MS DOS from the hard drive 2 The ADM specific functions performed by AUTOEXEC BAT commands to load the 3C5X9PD Packet Driver terminate and stay resident TSR program then to synchronise the ADM date and time with that of the master computer on the LSWT network 3 Finally the initialisation file named AUXILARY INI is downloaded using FTP from the master computer 3 1 1 3C5X9PD Packet Driver TSR The 3C5X9PD Packet Driver TSR is a program that makes the ethernet Network Interface Card NIC easy for MS DOS programs to use It provides a consistent set of interface functions to access the NIC hardware Each NIC manufacturer provides the drivers specific to their NIC The ADM uses a 3Com Company 3C509 NIC which requires the 3CX9PD TSR driver from 3Com All the ADM programs which make use of the ethernet network use this packet driver to send and receive information over the network 3 1 2 Date and Time Synchronisation The modules providing data to the LSWT master computer are all synchronised to the master computer s date and time during initialisation This allows data packets to be time stamped It also all
14. e of the panel as seen in the LSWT control room DSTO TR 1215 Figure 1 The LSWT Auxiliary Data Module AUXILIARY PANEL Digital Inputs 1 amp 2 PARALLEL 1 0 Digital Outputs 1 amp 2 gt a 1 gt t Tachometer Inputs 1 amp 2 3 4 5 6 Tachometer from Working Section AUXILIARY MOTOR TACHO gt 7 1 2 AUXILIARY I O FROM TUNNEL Non Dedicated 1 2 from Working Section N 3 4 ANALOG I P 6 7 ANALOG O P 1 2 RS232 PORTS Figure 2 Auxiliary Interface Connector Panel PC Com 1 amp 2 DSTO TR 1215 ALLA Y PANEL pe a ume o 0 i Figure 3 Visual Appearance of the Auxiliary Interface Connector Panel 2 1 PXB 721 Digital Interface Board The digital I O port interface provided by this board consists of 72 digital lines The board design groups these as a number of 8 bit ports The 8 bit ports are accessed in pairs as 16 bit ports in the ADM operating software The ports are provided by three Intel 8255 digital interfacing integrated circuits IC per PXB 721 board The IC devices are mounted on daughter boards plugged to the respective PXB 721 board In addition each daughter board has an I O header connector The headers are referred to as Hl to H6 parallelling the designations of the ICs The fact that there are two separate PXB 721 boards means there are six 8255 ICs in all This report
15. ed by a write operation to this register 3 5 6 DADATI This register holds the low byte of the 12 bit word to be loaded into DAC1 for aDAC conversion and is addressed as base plus offset 4 DADATI also holds the high 4 bits of the DAT conversion and this is addressed with offset 5 3 5 7 TMRCTR The PC 74LA internal clock has a frequency of 600 kH This register enables the selection of a suitable divider to provide the preferred frequency There 64 selections enabling a wide range of divider values and therefore clock frequencies Reference to the PC 74LA User Manual is the best means of making a special selection The default value for the divider is 100 giving a clock frequency of 6 kH 4 References Quatech Quatech PXB 721 User manual Re7v B Quatech Inc 662 Wolf Ledges Parkway Akron Ohio 44311 USA Interworld Electronics User Manual for PC 74 First Ed 1988 Interworld Electronics amp Computer Ind Aust P L 933 Glenhuntly Road Caulfield Sth 3162 Australia Intel Microprocessor and Peripheral Handbook Vol 2 Intel Corporation 3065 Bowers Avenue Santa Clara California 95051 USA 5 Acknowledgements I would like to acknowledge the assistance of M Spataro and O Holland for software advice and the blending in of the ethernet modules and I Kerton who wrote the original software modules for the digital port control OUTSIDE AUSTRALIA ABSTRACTING AND INFORMATION ORGANISATIONS Library Chemical
16. ised the configuration data is listed in Table 5 Table 5 Configuration data for the Digital Ports Option A B Input A B Output Input Data Value 9BH 80H 90H The control registers are set to these values by calls to the C function SETIOPORTS in AUXILARY C 3 5 PC 74LA Board Configuration The PC 74LA board is configured by a combination of hardware links and program actions The hardware links are used to set base address interrupt level DMA level DAC output range Differential or Single ended input and the ADC input range The hardware setup is considered as fixed Should a change be required to accommodate a special function in the future the operator is advised to refer to the PC 74LA User Manual The PC 74LA board has eight registers to control aspects of configuration and data handling They are addressed by increments from the base address commencing with the base address 3 5 1 PC 74LA Register Structure Eight locations starting with the Board base address in AT I O space provide the programmable registers of the PC 74LA Board They are described in Table 6 3 Interworld Electronics amp Computer Industries Aust Pty Ltd DSTO TR 1215 Table 6 Register Locations of the PC 74LA Plug in Board Base Offset Title Function ADCSR AD Control Status ADGCR AD Gain Channel Selection ADDAT DADATO Low Byte ADC I O Data ADDAT DADATO High Byte ADC I O Data DADATI Low Byte DAC1 Data DADAT1 High Byte DACI Data D
17. lth of Australia 2001 AR 012 026 October 2001 APPROVED FOR PUBLIC RELEASE An Auxiliary Interface Instrumentation Module for the AMRL Low Speed Wind Tunnel Data Acquisition System Executive Summary An electronic module called the Auxiliary Data Module ADM is described which provides the functions required to enable external data input or specific data extraction from the LSWT data acquisition system The ADM is a PC based unit configured to mechanically conform to the existing console appearance and VME mounting requirements The module is accessable to the Master computer via the LSWT ethernet network Auxiliary data may consist of input signals from additional transducers or data extracted for recording on external devices or control signals to carry out a remote task The ADM provides a suite of user interfaces which include two 16 bit digital input ports two 16 bit digital output ports and two dedicated digital input ports for the measurement of tachometer data from powered propellors on wind tunnel models In addition the ADM includes a plug in analog interface board which provides eight differential analog input channels and two output channels These analog functions are able to be reconfigured manually by using switches and links on the board for the selection of input and output voltage range and polarity options All analog I O channels have 12 bit resolution Authors F J Bird Air Operations Division Fred Bird
18. minally TTL compatible and it is therefore quite rugged The steady state signal characteristics for peripheral application are as follows Input Low voltage Vi 0 5 to 0 8 Volts Input High Voltage V n 2 0 to 5 10 Volts Output Low Voltage Vor 0 45 Volts Max Output High Voltage Von 2 4 Volts Min 2 1 2 Digital Interface Panel Connector Pin Functions The pin functions of the Digital I O include digital signal lines and ground reference lines Table 1 lists the pin numbers and their functions which are applicable to all the Digital I O D37 connectors Table 1 The pin allocations of the Digital Interface Panel Dig Line i Dig Line 2 1 3 Tachometer Input Interface The only dedicated function of the ADM is acquiring the model tachometer signals The 8255 IC chips IC5 and IC6 are used for this purpose The D37 connectors on the connection DSTO TR 1215 panel designated 5 and 6 are connected to these ICs through headers H5 and H6 The D37 connector pin allocation is identical to Table 1 for the digital I O functions The tachometer signals consist of four digit binary coded decimal BCD values The numbers are serialised at the transmitting ends of the tachometer input signal transmission lines Each value is received as a serial set of four digits Each digit is represented as a four bit binary number The values are converted to hexadecimal values and passed to the Module database via the tasks Model Tacho1 and ModelTacho
19. o denote a log file To clarify this scheme AUX12345 LOG would have been created on February 2 4 at 3 45 AM Likewise AUXBVN59 LOG corresponds to December 315 at 11 59 PM DSTO TR 1215 3 2 1 2 Read the Initialisation File The AUXILARY program reads information it requires from a file named AUXILARY INT The information is used to set up the network interface The network interface is provided with an Internet Protocol IP number an IP address mask and an IP broadcast address These allow the module to set up its own local address on the network Further network related information that is also obtained from the initialisation file is the IP address of the LSWT master computer and the ethernet hardware address of that computer However the information provided by the ADM is required by more than just the LSWT master computer and this operational requirement is satisfied by broadcasting ADM information to all devices on the LSWT network The final piece of network interface information read from the initialisation file is the interrupt number used by the PKTDRVR C packet driver This allows the AUXILARY program to send and receive ethernet packets to and from the 3C5X9PD packet driver TSR 3 3 PC YO Bus Address Decoding The module AUXILARY C operates the data acquisition boards to obtain auxiliary data The boards occupy bus I O space using the addresses listed in Table 3 for data and port control The Module program use
20. ows easier cross checking of the log files written to a module s hard 2 More information can be obtained on Packet Drivers from the FAQ at http seagull rtd com pub tcpip other faqs pktdrv faq DSTO TR 1215 disk against data files written to the master computer s disk should that be required The program PDTSTNET uses the packet driver to send packets to the master computer that ask for the current date and time The information returned by the master computer is for UTC and must be corrected by a factor of 10 hours to the local time zone at AMRL Melbourne AEST If daylight saving is in operation the correction is 11 hours Once the correction is applied PDTSTNET sets the DOS clock to the local time equivalent of the master computer s date and time 3 1 3 Downloading an Initialisation File The master computer partly controls each LSWT Data Acquisition System module s operation through the initialisation files Much of the ADM operation is controlled by information in a file named AUXILARY INI This file is downloaded during every ADM initialisation so that the copy on the ADM hard disk is always up to date with the master file held on the disk of the master computer The File Transfer Protocol FTP is used to reliably copy the file over the network to the ADM disk The program FTP uses the packet driver to access the network and takes commands from the file FTPINLCMD in the LSWT SOFTWARE AUXILARY directory These comm
21. s Analog Output 1 and 2 2 3 Network Interface Card NIC The ethernet board used for the wind tunnel modules based on the PC platform is the 3COM Etherlink III board The interrupt level for the ADM ethernet handling is IRQ11 3 Module Software The operating software consists of C version 3 0 modules supported by modules of the multitasking program Real Time Kernel RTK version 4 5 The C modules include functions to control database access and the plug in boards and they use manufacturer s library modules where appropriate The C modules are all required to be entered in the C project file AUXILARY prj as are library files pertaining to the multi tasking Real Time Kernel RTK enables programmers DSTO TR 1215 to minimise waiting during interrupts communications or other activities In addition RTK allows a prioritisation of the program tasks so thatimportant tasks are carried out as required On start up the PC loads the packet driver PKTDRVR C before using File Transfer Protocol FTP to copy the file AUXILARY INI from the master computer Following this the working directory is changed to C LSWT SOFTWARE AUXILARY to run AUXILARY EXE The module DB_HNDLR C calls functions for handling data transfers to or from the module database Communication packets are formed and decoded by the module PKTDRVR C A further program module called ENETDRVR C contains the ethernet interrupt handling segments It also receives ve
22. s the C function SETIOPORTS C to pass control data to the control registers The function needs only the boards base addresses to do this The control data is defined in the program for each configuration required ie output or input for the respective ports Table 3 Board addresses for data and port control PXB 721 Base and Data Registers Board 1 Base 210H Board 2 Base 220H Digital In 1 210 218H High Byte 211 219H Low Byte Digital In 2 214H High Byte 215H Low Byte Digital Out 1 218 224H High Byte 219 225H Low Byte Tachometer 1 224 210H Tachometer 2 228 220H PC 74LA Control and Data Registers Status Reg ADCSR 310H Gain Chan ADGCR 31H Conv Data ADDATL 312H Low Byte Conv Data ADDATH 313H High Byte 0 DADATOL 312H Low Byte 0 In DADATOH 313H High Byte DAC1 In DADATIL 314H Low Byte DAC1 In DADAT1H 315H High Byte Timer Cont TMRCTR 317H 11 DSTO TR 1215 12 3 4 PXB 721 Board Configuration Configuring the Digital ports to enable input or output functions is done by passing defined values into the control register within each 8255 IC This is a function of the Module program AUXILARY EXE The Control register AT I O bus addresses are listed in Table 4 Table 4 Digital Port addresses on the PXB 721 plug in board IC Device IC2 IC3 IC4 IC5 IC6 Register address 23H 217H 21BH 2235 27H 22BH The configuration options are few Since only ports A and B of each 8255 IC are to be util
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