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Section Three

Function Description

© National Instruments Corporation

3-3

GPIB-LPT User Manual

GPIB Handshaking

GPIB handshaking converts PC parallel port handshaking into GPIB handshaking protocol.  This
process is transparent to you.

GPIB Addressing

On printer/plotter initialization, the GPIB-LPT checks to see if the printer/plotter is listening; if not,
the GPIB-LPT addresses it as a listener using the GPIB listen address on the onboard switches.

Summary of Contents for GPIB-LPT

Page 1: ...Copyright 1989 1990 National Instruments Corporation All Rights Reserved GPIB LPT User Manual October 1989 Edition Part Number 320161 01...

Page 2: ...National Instruments Corporation 6504 Bridge Point Parkway Austin TX 78730 5039 512 794 0100 800 IEEE 488 Fax 512 794 8411...

Page 3: ...or repair must be clearly marked on the outside of the package with an RMA number Defects caused by misuse abuse or shipment are not covered The GPIB LPT Diagnostic Package software program is provide...

Page 4: ...tallation However the chances of interference are much less if the equipment is used according to this instruction manual If the equipment does cause interference to radio or television reception whic...

Page 5: ...Four Running Diagnostic Tests describes how to run the diagnostic tests that are shipped with the GPIB LPT Section Five Programming the GPIB LPT contains specific information about the GPIB LPT regis...

Page 6: ...oration Related Documents The following documents are references that cover in greater detail specific topics introduced in this manual ANSI IEEE Standard 488 1978 IEEE Standard Digital Interface for...

Page 7: ...Control Latches 3 2 Data Transceivers 3 2 Data Wrap Control Wrap and Status Buffers 3 2 External Device Listen Address Switch 3 2 GPIB Handshaking 3 3 GPIB Addressing 3 3 Section Four Running Diagnos...

Page 8: ...isteners and Controllers A 1 System Controller and Active Controller A 2 GPIB Signals A 2 Data Lines A 3 Handshake Lines A 3 NRFD not ready for data A 3 NDAC not data accepted A 3 DAV data valid A 3 I...

Page 9: ...SRQ ON and Address 5 2 5 Figure 2 4 Setting for Address 6 hex 2 6 Figure 2 5 Switch Setting for REN ON IFC ON and SRQ OFF 2 7 Figure 3 1 GPIB LPT Block Diagram 3 1 Figure 4 1 Plotter Output 4 2 Figure...

Page 10: ...printer and plotter output Features The GPIB LPT has the following hardware features emulates the standard PC parallel printer interface so that no additional software is needed can be configured as e...

Page 11: ...orporation Figure 1 1 shows the GPIB LPT interface board Figure 1 1 GPIB LPT Board The GPIB LPT works in most true IBM compatible computers It does not work in the TI Professional Computer because it...

Page 12: ...test that is described in Section Four Running Diagnostic Tests Make sure each of these items is in your kit If any item is missing contact National Instruments Optional Equipment Item Part Number Do...

Page 13: ...truments Corporation 2 1 GPIB LPT User Manual Section Two Configuration and Installation Figure 2 1 shows the locations of the GPIB LPT configuration jumpers and switches Figure 2 1 GPIB LPT Parts Loc...

Page 14: ...hen 278 LPT3 If only one device is installed that device is named LPT1 regardless of what its I O address is If there is more than one parallel device installed the first one found is assigned LPT1 th...

Page 15: ...ations GPIB LPT Default Optional Base I O Address 278 27C 3BC and 378 37C Interrupt Level 5 7 If you need to change the factory settings continue on If you do not need to change the factory settings s...

Page 16: ...nochrome Adapter W2 I5 P2 I7 P1 W1 PA MA a Jumpers Set to Base I O Address 3BC hex and Interrupt Level 7 Monochrome Display and Printer Adapter W2 I5 P2 I7 P1 W1 PA MA b Jumpers Set to Base I O Addres...

Page 17: ...N position enables REN The OFF position disables REN IFC Enables disables the Interface Clear IFC option on the GPIB LPT If enabled the GPIB LPT issues an IFC when it is initialized The ON position en...

Page 18: ...evice with address 6 hex The address varies with each device so check the address of your device and set these lower five bits O F F O N This side down for logic 0 This side down for logic 1 REN IFC S...

Page 19: ...for logic 0 This side down for logic 1 REN IFC SRQ 1 2 4 8 16 U18 Key side you must press down for REN ON IFC ON used for setting Listen Address and SRQ OFF Off 1 On 0 Figure 2 5 Switch Setting for RE...

Page 20: ...for specific instructions and warnings 1 Turn off your computer 2 Remove the plug from its power source 3 Remove the top cover or access port to the I O channel 4 Remove the expansion slot cover on t...

Page 21: ...hows a block diagram of the GPIB LPT PC I O Channel Address Decoding Config Jumpers Data Bus Address Bus Data Wrap Buffers Data Latch Control Latch GPIB GPIB Handshaking GPIB Addressing External Devic...

Page 22: ...nd control latches emulate the data and control registers of the standard IBM PC parallel port adapter Writing to these latches controls output to the printer plotter Data Transceivers Data transceive...

Page 23: ...king converts PC parallel port handshaking into GPIB handshaking protocol This process is transparent to you GPIB Addressing On printer plotter initialization the GPIB LPT checks to see if the printer...

Page 24: ...GPIB LPT DIAGNOSTIC TESTS This program assumes the GPIB LPT is configured at base address 278 Parallel adapter 2 If you reconfigured your GPIB LPT you must change the address that this program uses T...

Page 25: ...LMNOPQRSTUVWXYZ _ abcdefghi jklmnopqrstuvwxyz 0123456789 ABCDEFG HIJKLMNOPQRSTUVWXYZ _ abcdefghijklmnopqrstuvwxyz If the printer does not respond an error message appears on the screen along with a me...

Page 26: ...configuration This command is used to change the base address of the GPIB LPT to match the actual board settings If you have changed the jumper settings to something different than the default setting...

Page 27: ...PT This section presents specific information about the GPIB LPT Parallel Port Emulator registers along with software examples The GPIB LPT Registers The GPIB LPT has three onboard registers that are...

Page 28: ...ess Base I O Address 0 hex Attributes Read Write 7 6 5 4 3 2 1 0 D6 D5 D7 D4 D3 D2 D1 D0 R W Writing to this address causes data to be latched in the GPIB LPT DATA register Reading this address sends...

Page 29: ...ggered when the Not Data Accepted NDAC GPIB handshake line is unasserted by the external GPIB device 5r PE Paper Error Bit This bit indicates to the parallel port adapter that a paper error has occurr...

Page 30: ...Corporation Bit Mnemonic Description 3r ERROR Error Bit This bit indicates Paper End state Off line state and Error state a logical 0 indicates one of these states This bit is not used by the GPIB LP...

Page 31: ...ges from active to inactive 3w SLCTIN Select In Bit When this bit is set the GPIB LPT can source data onto the GPIB data lines 2w INIT Initialize Bit Setting and then clearing this bit initializes the...

Page 32: ...ating System The following DOS command sends the file example txt to the GPIB device connected to the GPIB LPT type example txt lpt2 Note You press your RETURN or ENTER key to execute these commands S...

Page 33: ...adapter in the system LPT1 these will only send data to the GPIB device if the GPIB LPT is LPT1 Writing a GPIB LPT Driver When you use an IBM BIOS driver it performs the following steps to send a cha...

Page 34: ...tine The interrupt handler routine is called every time an ACK pulse interrupt is seen by the processor It disables the GPIB LPT interrupt calls the PRINT subroutine and re arms the 8259A Interrupt Co...

Page 35: ...s The only constraint for the GPIB LPT is the length of the STROBE pulse The following sequence guarantees a pulse width between 1 and 5 sec mov al 0Dh STROBE mask mov dx CTRL dx points to the CTRL re...

Page 36: ...sing and unaddressing devices and setting devices for remote or local programming Note The term command as used here should not be confused with some device instructions which are also called commands...

Page 37: ...he active or addressed Talker or Listener must be changed The Controller function is usually handled by a computer System Controller and Active Controller Although there can be multiple Controllers on...

Page 38: ...and most data use the 7 bit ASCII or ISO code set in which case the eighth bit DIO8 is unused or used for parity Handshake Lines Three lines asynchronously control the transfer of message bytes among...

Page 39: ...ion across the interface ATN attention The Controller drives ATN true when it uses the data lines to send commands and false when it allows a Talker to send data messages IFC interface clear The Syste...

Page 40: ...cs Devices are usually connected with a cable assembly consisting of a shielded 24 conductor cable with both a plug and receptacle at each end This design allows devices to be connected in either a li...

Page 41: ...connector is the Amphenol or Cinch Series 57 MICRORIBBON or AMP CHAMP type An adapter cable using non standard cable and or connector is used for special interconnect applications The GPIB uses negat...

Page 42: ...designed for the physical distance between devices and the number of devices on the bus is limited The following restrictions are typical A maximum separation of 4 m between any two devices and an av...

Page 43: ...National Instruments Corporation B 1 GPIB LPT User Manual Appendix B Multiline Interface Messages The following tables are multiline interface messages sent and received with ATN TRUE...

Page 44: ...017 15 SI 2F 057 47 MLA15 10 020 16 DLE 30 060 48 0 MLA16 11 021 17 DC1 LLO 31 061 49 1 MLA17 12 022 18 DC2 32 062 50 2 MLA18 13 023 19 DC3 33 063 51 3 MLA19 14 024 20 DC4 DCL 34 064 52 4 MLA20 15 02...

Page 45: ...TA13 6D 155 109 m MSA13 PPE 4E 116 78 N MTA14 6E 156 110 n MSA14 PPE 4F 117 79 O MTA15 6F 157 111 o MSA15 PPE 50 120 80 P MTA16 70 160 112 p MSA16 PPD 51 121 81 Q MTA17 71 161 113 q MSA17 PPD 52 122 8...

Page 46: ...GPIB LPT board Power Requirement 5 VDC 5 0 40 A typical Physical Dimensions 4 2 in x 5 5 in I O Connector IEEE 488 Standard 24 pin Operation Environment Component Temperature 0 to 70 C Relative humidi...

Page 47: ...User Manual Edition Date October 1989 Part Number 320161 01 Please comment on the completeness clarity and organization of the manual If you find errors in the manual please record the page numbers an...

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