Related Manuals for National Instruments GPIB-COM
Summary of Contents for National Instruments GPIB-COM
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Page 1: User Manual
GPIB-COM User Manual June 1990 Edition Part Number 320197-01 © Copyright 1989, 1991 National Instruments Corporation. All Rights Reserved. - Page 2 National Instruments Corporation 6504 Bridge Point Parkway Austin, TX 78730-5039 (512) 794-0100 (800) IEEE-488 (toll-free U.S. and Canada) Technical support fax: (512) 794-5678...
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Page 3: Limited Warranty
Limited Warranty The GPIB-COM is warranted against defects in materials and workmanship for a period of two years from date of shipment. National Instruments will repair or replace equipment which proves to be defective during the warranty period. This warranty includes parts and labor. A Return Material Authorization (RMA) number must be obtained from National Instruments before any equipment is returned for repair. - Page 4 Be sure that the equipment is plugged into a grounded outlet and that the grounding has not been defeated with a cheater plug. If necessary, consult National Instruments or an experienced radio/television technician for additional suggestions. The following booklet prepared by the FCC may also be helpful: How to Identify and Resolve Radio-TV Interference Problems.
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Page 5: Organization Of This Manual
Organization of This Manual This manual is divided into the following sections: Section One, Introduction, contains a brief description of the GPIB-COM including a listing of its features, accessories, and components. Section Two, Configuration and Installation, describes how to configure and install the GPIB- COM into your system. -
Page 6: Abbreviations Used In This Manual
Celsius hexadecimal inch input/output kbyte 1000 bytes meter Mbyte megabyte megahertz msec millisecond read read/write second volt volts direct current write GPIB-COM User Manual © National Instruments Corporation... -
Page 7: Table Of Contents
Switch and Jumper Settings... 2-3 Base I/O Address and Interrupt Selection... 2-3 Talk/Listen Modes ... 2-4 Talk/Listen Address and Special Function Selection... 2-5 Installation... 2-7 Special Considerations When Using the GPIB-COM... 2-8 Section Three Function Description ... 3-1 The GPIB-COM Interface ... 3-1 GPIB-COM Components... - Page 8 Modem Control Register ... 5-10 Line Status Register ... 5-12 Modem Status Register... 5-14 Programming the Serial Adapter ... 5-16 Polling Method ... 5-16 Interrupt-Driven Method... 5-16 The GPIB-COM Controller Function... 5-17 Appendix A Specifications ... A-1 Appendix B Multiline Interface Command Messages...
- Page 9 Figure 2-2. Possible Settings for GPIB-COM Jumpers... 2-4 Figure 2-3. Jumper W1 Settings ... 2-4 Figure 2-4. Switch Setting for REN* OFF, IFC* ON, SRQ* ON, and Listen Address 5 ... 2-5 Figure 2-5. Listen Address Setting for Listen Address 10 Hex... 2-6 Figure 2-6.
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Page 10: Section One Introduction
IEEE-488 printers and plotters. It can be used with any serial port software on the PC. The GPIB-COM looks like a standard serial port to the IBM PC operating system and software. It can be used to interface IEEE-488 devices to any PC software that uses the serial ports. -
Page 11: What Your Kit Should Contain
Note: The GPIB-COM Diagnostic Test Diskette contains the com.exe diagnostic 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. GPIB-COM User Manual Figure 1-1. -
Page 12: Optional Equipment
* In order to meet FCC emission limits for a Class B device, you must use a shielded GPIB cable. Operating this equipment with a non-shielded cable may cause interference to radio and television reception in residential areas. © National Instruments Corporation Part Number 763061-01... -
Page 13: Section Two Configuration And Installation
Section Two Configuration and Installation This section contains information on how to configure and install the GPIB-COM into your system. Configuration Figure 2-1 shows the locations of the GPIB-COM configuration jumpers and switches. Figure 2-1. GPIB-COM Parts Locator Diagram © National Instruments Corporation... - Page 14 Note: DOS and BIOS only recognize base addresses 3F8 and 2F8. The GPIB-COM is shipped from the factory set to 3F8. It must be reconfigured to another base address if another device (such as a printer adapter card or a built-in serial port) is already at that address.
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Page 15: Switch And Jumper Settings
Base I/O Address and Interrupt Selection The base I/O address and interrupt line used by the GPIB-COM are determined by the jumpers located at positions W2 and W5. The jumpers are set at the factory for base I/O address 3F8 hex and interrupt level 4. -
Page 16: Talk/Listen Modes
Figure 2-2. Possible Settings for GPIB-COM Jumpers Talk/Listen Modes If you are using your GPIB-COM with a listen-only printer or plotter, you can configure the GPIB-COM for a talk-only mode. In this mode, the GPIB-COM is always a Talker and never sends any interface commands. -
Page 17: Talk/Listen Address And Special Function Selection
GPIB controller responsibilities. In the talk/listen mode, the first five switches set the talk or listen address of the external device(s) that will be attached to the GPIB-COM. In the talk-only mode, the GPIB-COM does not send a talk or listen address. -
Page 18: Figure 2-5. Listen Address Setting For Listen Address 10 Hex
Configuration and Installation Figure 2-5 shows the switch configuration needed when using a device with listen address 10 hex. The listen address varies with each device so check the listen address of your device and set these five bits accordingly. -
Page 19: Installation
5. Insert the GPIB-COM in an unused full-length slot with the IEEE-488 receptacle sticking out of the opening of the back panel. It may be a tight fit, but do not force the board into place. 6. Screw the right angle mounting bracket of the GPIB-COM to the back panel rail of your computer. -
Page 20: Special Considerations When Using The Gpib-Com
COM2 are accessed through DOS. Sometimes a timeout error may occur when writing through the GPIB-COM to a slow device such as a printer or a plotter. If this happens, use the MODE command to disable the timeout function by typing MODE COM1:12,,,,P. Some software applications use the COM port baud rate setting to control the data transmission speed. -
Page 21: Section Three Function Description
Section Three Function Description This section contains a block diagram of the GPIB-COM, followed by a description of each of its functional components. The GPIB-COM Interface The GPIB-COM is a completely transparent interface between GPIB devices and any IBM PC software that uses serial ports. -
Page 22: Figure 3-1. Block Diagram Of Gpib-Com
Function Description Figure 3-1 shows a block diagram of the GPIB-COM. IRQ3 IRQ4 Address Bus IOW* IOR* Data Bus GPIB-COM User Manual Config. Interrupt Jumpers Control Config. Jumpers Address Decoding Direction Buffer Mode Control Logic Acceptor Source Handshake Handshake GPIB... -
Page 23: Gpib-Com Components
This circuitry converts PC serial port handshaking into GPIB handshaking. This process is completely software-transparent. Mode Control Logic This circuitry determines whether the GPIB-COM should be a Talker (and the target device a Listener) or a Listener (and the target device a Talker). Interrupt Control Logic This circuitry generates and masks interrupts on GPIB conditions which correspond to the conditions that would cause the INS8250A circuit to generate an interrupt. -
Page 24: Direction Buffers
These buffers control the direction in which data information travels. GPIB Transceivers The GPIB-COM is interfaced to the IEEE-488 bus by National Semiconductor 75160A and 75162A transceivers. These integrated circuits are specifically designed to provide power- up/power-down bus protection (glitch-free). The GPIB-COM counts as one IEEE-488 bus load, thereby allowing an additional 14 devices to be connected before exceeding the bus loading restrictions imposed by the IEEE-488. -
Page 25: Section Four Running Diagnostic Tests
GPIB printer or plotter. To run a GPIB-COM diagnostic test, connect a printer or plotter to the GPIB and run the program com.exe from the GPIB-COM diagnostic test diskette. The following message will appear on the... -
Page 26: Plotter Test
National Instruments. -2 plotter test Select this test to verify the configuration of the GPIB-COM when connecting it to a GPIB HP-GL plotter. This test will send output to the plotter. -
Page 27: C Change Com Configuration
Instruments. -c change COM configuration This command is used to change the base address of the GPIB-COM to match the actual board settings. If you have changed the jumper settings to something different than the default settings, you must run this command. -
Page 28: Section Five Programming The Gpib-Com
Programming the GPIB-COM This section presents a description of the GPIB-COM Serial Port Emulator registers and information on programming the GPIB-COM. You need to use this section only if you are writing your own serial port device driver. The GPIB-COM Registers IBM's serial adapter is a plug-in card for the PC that handles RS-232 communication. -
Page 29: Transmitter Holding Register
DLAB bit in Line Control Register = 0 The Transmitter Holding Register contains the character to be sent to the serial output, with bit 0 being the least significant and bit 7 the most significant. It functions identically on the GPIB-COM and the INS8250. -
Page 30: Receive Buffer Register
DLAB bit in Line Control Register = 0 The Receive Buffer Register contains the character received from the serial input, with bit 0 being the least significant and bit 7 the most significant. It functions identically on the GPIB-COM and the INS8250. -
Page 31: Divisor Latch Least Significant Byte (Lsb) Register
The 16-bit number formed by the Divisor Latch LSB and MSB is divided into a 1.8432 MHz clock to produce the baud rate. The Divisor Latch Registers are ignored by the GPIB-COM circuitry; however, they are available on the GPIB-COM and can be written to and read by software. -
Page 32: Interrupt Enable Register
The modem status interrupt occurs when any of bits 0 through 3 of the Modem Status Register are set to logical 1. This bit is identical on the GPIB-COM and the INS8250, but bits 0 through 3 of the Modem Status Register are set for different conditions as noted under the Modem Status Register description. - Page 33 The transmitter holding register empty interrupt occurs when the INS8250 becomes ready to send another character. This bit functions identically on the GPIB-COM and the INS8250. Received Data Available Interrupt Enable Bit This bit enables a received data available interrupt when set. The...
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Page 34: Interrupt Identification Register
This register functions identically on the GPIB- COM and the INS8250. Mnemonic 7-3r 2-1r ID[1-0] © National Instruments Corporation Description Reserved Bits 7 through 3 These bits always read as 0. Identify Interrupt Register Bits These two bits identify the interrupt that is pending. If more than one interrupt is pending, only the one with the highest priority is identified. -
Page 35: Line Control Register
MSB, and cleared to access the Transmitter Holding Register, the Receive Buffer Register, and the Interrupt Enable Register. This bit functions identically on the GPIB-COM and the INS8250. Set Break Control Bit When set, this bit causes the SOUT line of the serial cable to be forced to a logical 0 state. -
Page 36: Table 5-3. Word Length Select Bits
STP and EVEN bits (bits 4 and 5). If this bit is clear, the INS8250 will not generate or check parity bits. This bit is ignored by the GPIB-COM. Stop Bit Control Bit This bit controls the number of stop bits sent and verified by the INS8250. -
Page 37: Modem Control Register
The RTS serial port output is the inverse of this bit. When this bit is set, it indicates that the Controller is ready to send data. On the GPIB-COM, this bit is used along with the DTR bit to control the CTS bit of the Modem Status Register. - Page 38 The DTR serial port output is the inverse of this bit. This bit is set when the Controller is ready to communicate. On the GPIB-COM, this bit is used along with the RTS bit to control the CTS bit of the Modem Status Register.
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Page 39: Line Status Register
Shift Register onto the serial output line. On the GPIB-COM, there is no shift register so this bit behaves exactly the same as the THRE bit. Transmitter Holding Register Empty Bit... - Page 40 It is cleared when the processor reads the Line Status Register. On the GPIB-COM, this bit is set when the SRQ* line of the GPIB is asserted. When the special function selection DIP switch has been set to disable the SRQ feature, this bit is always clear.
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Page 41: Modem Status Register
The Modem Status Register gives the state of the modem control lines and tells whether any of these lines have changed state since the register was last read. This register is read only on the GPIB-COM. Writing to this register will not change its contents. The function of each bit in this register is explained below. - Page 42 This bit is set when the CTS input changes state and cleared when the processor reads the Modem Status Register. On the GPIB-COM, this bit is the logical AND of the DTR and RTS bits of the Modem Control Register.
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Page 43: Programming The Serial Adapter
Programming the GPIB-COM Section Five Programming the Serial Adapter The operation of the serial adapter is controlled by software, either IBM BIOS or an application. To transfer data to and from the serial port, the communications parameters must first be set up in the following manner: 1. -
Page 44: The Gpib-Com Controller Function
COM sets the THRE bit of the Line Status Register to 0, puts the contents of that register on the GPIB data lines, and begins the source handshake sequence. When the Listener releases NDAC*, the THRE bit is set back to 1 and the GPIB-COM waits for another byte to be written into the Transmitter Holding Register. -
Page 45: Appendix A Specifications
Appendix A Specifications This appendix lists the specifications of the GPIB-COM board. Power Requirement +5 VDC ( 5%) Physical Dimensions I/O Connector Operating Environment Component Temperature Relative Humidity Emissions Storage Environment Temperature Relative Humidity © National Instruments Corporation 0.75 A typical 4.2 in. -
Page 46: Appendix B Multiline Interface Command Messages
Appendix B Multiline Interface Command Messages The following tables are multiline interface messages (sent and received with ATN TRUE). © National Instruments Corporation GPIB-COM User Manual... - Page 47 ASCII Msg Message Definitions Device Clear Group Execute Trigger Go To Local Local Lockout My Listen Address GPIB-COM User Manual Hex Oct My Secondary Address My Talk Address Parallel Poll Configure Parallel Poll Disable © National Instruments Corporation Appendix B...
- Page 48 Appendix B Multiline Interface Messages Hex Oct Dec ASCII Parallel Poll Enable Parallel Poll Unconfigure Selected Device Clear Serial Poll Disable © National Instruments Corporation Multiline Interface Command Messages MTA0 MTA1 MTA2 MTA3 MTA4 MTA5 MTA6 MTA7 MTA8 MTA9 MTA10...
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Page 49: Appendix C Operation Of The Gpib
The switching center (Controller) monitors the communications network (GPIB). When the center (Controller) notices that a party (device) wants to make a call (send a data message), it connects the caller (Talker) to the receiver (Listener). © National Instruments Corporation GPIB-COM User Manual... -
Page 50: System Controller And Active Controller
The interface bus consists of 16 signal lines and 8 ground return or shield drain lines. The 16 signal lines are divided into three groups: • eight data lines • three handshake lines • five interface management lines GPIB-COM User Manual © National Instruments Corporation Appendix C... -
Page 51: Data Lines
NDAC (not data accepted) NDAC indicates when a device has or has not accepted a message byte. The line is driven by all devices when receiving commands and by Listeners when receiving data messages. © National Instruments Corporation DIO5* DIO6*... -
Page 52: Dav (Data Valid
The EOI line has two purposes. The Talker uses the EOI line to mark the end of a message string. The Active Controller uses the EOI line to tell devices to identify their responses in a parallel poll. GPIB-COM User Manual © National Instruments Corporation... -
Page 53: Physical And Electrical Characteristics
This design enables devices to be connected in either a linear or a star configuration, or a combination of the two. See Figures C-2 and C-3. Figure C-2. Linear Configuration of the GPIB Devices © National Instruments Corporation GPIB-COM User Manual... -
Page 54: Figure C-3. Star Configuration Of Gpib Devices
The GPIB uses negative logic with standard TTL logic levels. When DAV is true, for example, it is a TTL low level ( 0.8 V), and when DAV is false, it is a TTL high level ( 2.0 V). GPIB-COM User Manual © National Instruments Corporation... -
Page 55: Configuration Restrictions
A maximum separation of 4 m between any two devices and an average separation of 2 m over the entire bus. • A maximum total cable length of 20 m. • No more than 15 devices connected to each bus, with at least two-thirds powered-on. © National Instruments Corporation GPIB-COM User Manual Operation of the GPIB... - Page 56 User Comment Form National Instruments encourages you to comment on the documentation supplied with our products. This information helps us provide quality products to meet your needs. Title: GPIB-COM User Manual Edition Date June 1990 Part Number: 320197-01 Please comment on the completeness, clarity, and organization of the manual.
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