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Black Box IC026A-R2, IC026AE-R2 Figure 3-7. Switch SW1: Selecting the Serial Handshake.

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RS-232↔IEEE 488 INTERFACE CONVERTER

3.3.6 S

ERIAL

H

ANDSHAKE

Switch SW1-5 is used to select hardware [RTS/CTS] or software [Xon/Xoff]

serial handshake control.

With X-ON/X-OFF, the interface converter issues an X-OFF character [ASCII

value of $13] when its buffer memory is near full. When the X-OFF character

is sent, there are still more than 1000 character locations remaining to protect

against buffer overrun. When it is able to accept more information, the inter-

face converter issues an Xon character [ASCII value of $11]. The interface

converter also accepts X-ON/X-OFF on transmit from the serial host it is

communicating with. RTS/CTS serial control becomes inactive when X-

ON/X-OFF is enabled. The RTS output is, however, set to an active high

state. The CTS input is not used for this handshake and may be left

floating (unconnected).

With RTS/CTS, the interface converter un-asserts RTS (sets RTS low) when

its buffer memory is near full. When RTS is un-asserted, there are still more

than 1000 character locations remaining to protect against buffer overrun.

When it is able to accept more information, the interface converter asserts

RTS (sets RTS high). The interface converter will not transmit data to the

serial host if it detects the CTS input un-asserted (low) when configured

for this hardware handshake.

The factory-default serial control is hardware, RTS/CTS.

Figure 3-7. Switch SW1: Selecting the Serial Handshake.

Switch

Side

View

DOT

1 2 3 4 5 67 8

OPEN

RTS/CTS

1 2 3 4 5 67 8

OPEN

X-ON/X-OFF

Contents

Main RS-232IEEE 488 INTERFACE CONVERTER EUROPEAN UNION DECLARATION OF CONFORMITY WARNING! Failure to follow these directives voids emission and immunity compliance. Page Page Page CONTENTS Contents RS-232IEEE 488 INTERFACE CONVERTER CONTENTS 1. Specifications WARNING! CHAPTER 1: Specifications CAUTION 2. Introduction 2.1 Description 2.2 Abbreviations CHAPTER 2: Introduction 3. Getting Started 3.1 Inspection 3.2 Configuration Figure 3-1. Factory-Default Settings. SW3 SW2 SW1 3.3 Serial Port Settings Figure 3-2. Switch SW1: Selecting the Serial Baud Rate. Figure 3-3. Switch SW1: Selecting the Serial Word Length (Data Bits). Figure 3-4. Switch SW1: Selecting the Serial Stop Bits. Figure 3-5. Switch SW2: Selecting the Serial Parity. Figure 3-6. Switch SW2: Enabling or Disabling Echo. Figure 3-7. Switch SW1: Selecting the Serial Handshake. 3.4 Selecting Terminator Substitution Figure 3-8. Switch SW2: Selecting the Serial Terminator. Figure 3-9. Switch SW3: Selecting the IEEE Bus Terminator. 3.5 Selecting the Mode Figure 3-10. Switch SW2: Selecting the Mode. 3.6 Selecting the IEEE Address Figure 3-11. Switch SW3: Selecting the IEEE Address. 3.7 Feature Selections Figure 3-12. Switch SW1: Enabling or Disabling Talk Back on Terminator in Controller Mode. Figure 3-13. Switch SW2: Enabling or Disabling Talk Back on Timeout in Controller Mode. Figure 3-14. Switch SW1: Enabling or Disabling SRQ on Last Serial Terminator in Peripheral Mode. 3.8 Serial Interface Figure 3-15. Selecting RS-232 or RS-422 Signal Levels. Figure 3-16. Rear View of the Interface Converters Serial Connector. Page Page 3.9 General CAUTION Page RS-232IEEE 488 INTERFACE CONVERTER 4.1 Controller-Mode (Serial to IEEE) Operation 4. Controller Operation 4.2 Serial and IEEE Terminator Substitution 4.3 IEEE Address Selection Figure 4-1. Switch SW3: Selecting the IEEE Address. 4.4 Talk-Back Features Figure 4-2. Switch SW1: Enabling or Disabling Talk-Back on Terminator. Figure 4-3. Switch SW2: Enabling or Disabling Talk-Back on Timeout. Page 4.5 Plotter Applications Figure 4-4. A PC-Based Graphics System. Figure 4-5. Selecting RS-232 Signal Levels. Figure 4-6. Interface Converter Settings for Use with HP 7580A Plotter on an IBM PC. SW2 SW3 SW1 Figure 4-7. MacPlot Configuration Screen. Figure 4-8. A Macintosh Based Graphics System. Interface Converter IEEE 488 RS-422 Page Figure 4-10. Interface Converter Settings for Use with HP 7580A Plotter on a Macintosh. Page 5. Peripheral Operation 5.1 Peripheral-Mode Operation 5.2 Serial and IEEE Input Buffers 5.3 IEEE Data Transfers Page RS-232IEEE 488 INTERFACE CONVERTER Figure 5-1. Switch SW1: Enabling or Disabling SRQ on Last Terminator. Figure 5-2. Serial Poll Status Byte. 5.4 Serial-Poll Status-Byte Register Page 5.5 Use of Serial and Bus Terminators 5.6 IEEE 488 Bus Implementation Page 5.7 IEEE Address Selection Figure 5-3. SW3 View for IEEE Address Selection. 6. IEEE 488 Primer 6.1 History 6.2 General Structure Page Figure 6-1. IEEE 488 Bus Structure. 6.3 Send It to My Address 6.4 Bus Management Lines 6.5 Handshake Lines Figure 6-2. IEEE Bus Handshaking. 6.6 Data Lines 6.7 Multiline Commands Page 6.8 More on Service Requests Page 7.1 Theory of Operation 7. Theory of Operation and Board Layout 7.2 Board Layout CHAPTER 7: Theory of Operation and Board Layout Figure 7-1. Component Layout of the Interface Converters Motherboard. Figure 7-2. Component Layout of the Interface Converters Serial I/O board. APPENDIX A: Sample Dumb-Terminal Program Appendix A. Sample Dumb-Terminal Program Appendix B. Character Codes and IEEE Multiline Messages Page Index INDEX