Motorola MVME197LE user manual Figure A-2. Minimum EIA-232-D Connection

Page 74

A

EIA-232-D Interconnections

Another subject that needs to be considered is the use of ground pins. There are two pins labeled GND. Pin 7 is the SIGNAL GROUND and must be connected to the distant device to complete the circuit. Pin 1 is the CHASSIS GROUND, but it must be used with care. The chassis is connected to the power ground through the green wire in the power cord and must be connected to the chassis to be in compliance with the electrical code. The problem is that when units are connected to different electrical outlets, there may be several volts difference in ground potential. If pin 1 of the devices are interconnected with a cable, several amperes of current could result. This not only may be dangerous for the small wires in a typical cable, but could result in electrical noise that could cause errors. That is the reason that Figure A-1 shows no connection for pin 1. Normally, pin 7 should only be connected to the CHASSIS GROUND at one point and, if several terminals are used with one computer, the logical place for that point is at the computer. The terminal should not have a connection between the logic ground return and the chassis.

EIA-232-D

CONNECTOR

GND	1	O
TXD	2	O
RXD	3	O
RTS	4	O
CTS	5	O
DSR	6	O
GND	7	O
DCD	8	O
	∙
	∙
	∙
	∙
	∙
DTR	20	O

Figure A-2. Minimum EIA-232-D Connection

A-6	User’s Manual

Image 74

Contents MVME197LE MVME197LE/D2Restricted Rights Legend Preface Document TerminologyBIT Related Documentation Document Title Motorola Publication NumberPage Page Safety Summary Safety Depends on YOU Contents Appendix a List of Figures Xii List of Tables Xiv Introduction General DescriptionFeatures OteCharacteristics Specifications SpecificationsMVME197LE Specifications Cooling Requirements Equipment Required FCC ComplianceSupport Information Unpacking Instructions Hardware PreparationHardware Preparation and Installation VMEbus Connector P1 Configuration Switch S1 General Information Configuration SwitchesSwitch S1 S1-1 to S1-8 OFF -- All Ones Factory Configuration Connectors Installation InstructionsSwitch S6 MVME197LE Module Installation System Considerations MVME197LE/D2 Hardware Preparation and Installation Reset Switch S3 Controls and IndicatorsAbort Switch S2 Processor Bus Memory Map Front Panel Indicators DS1-DS6Memory Maps Processor Bus Memory Map Address Range Devices Accessed Port Size Local Devices Memory MapDetailed I/O Memory Maps 108 BusSwitch Register Memory Map100 110Memory Maps Ecdm CSR Register Memory Map ECDM0 ECDM1 ECDM2 ECDM3 ADDR/REGISTERDcam I2C Base Address = $C0 default Offset Dcam I2C Register Memory MapOperating Instructions VMEchip2 Memory Map Sheet 1 OffsetOperating Instructions Global Access BUS Watchdog Timeout Prescaler Adjust VMEchip2 Memory Map Sheet 2Operating Instructions VMEchip2 Memory Map Sheet 3 Operating Instructions VMEchip2 Memory Map Sheet 4 VMEchip2 Gcsr Base Address = $FFF40100Operating Instructions PCCchip2 Memory Map Printer PE Interrupt Control Register $FFF42033 Printer Fault Interrupt Control Register $FFF42031Printer SEL Interrupt Control Register $FFF42032 Printer Busy Interrupt Control Register $FFF42034Base Address Is $FFF45000 Cirrus Logic CD2400 Memory Map Offsets Size AccessCirrus Logic CD2401 Serial Port Memory Map Data Bits Address D31 D16 D15 12. MK48T08 BBRAM, TOD Clock Memory Map Accesses may be 8-bit or 32-bit, but not 16-bit11 C710 Scsi Memory Map Address Range Description Size BytesData Bits Address Function 13. Bbram Configuration Area Memory Map14. TOD Clock Memory Map 000000470476 BBRAM, TOD Clock Memory Map0460 01-W3869B03A VMEbus Accesses to the Local Peripheral BusVMEbus Memory Map 5000Multi-MPU Programming Considerations Local Reset OperationSoftware Initialization User’s Manual MC88110 MPU MVME197LE Functional DescriptionData Bus Structure Functional Description Mezzanine Address Bus Bus Data Bus 256 BusSwitchMC88110 Address Data MUX Address Memory ArrayOnboard Dram Battery Backup RAM and ClockFlash Memory Serial Port Interface VMEbus InterfaceInterfaces Printer Interface Ethernet InterfaceScsi Interface Programmable Tick TimersPeripheral Resources Scsi TerminationLocal Peripheral Bus Timeout Watchdog TimerProcessor Bus Timeout Interrupt SourcesMVME197LE/D2 Functional Description EIA-232-D Interconnections Pin Signal Signal Name and Description Number Mnemonic Table A-1. EIA-232-D InterconnectionsRing Indicator RI is sent by the modem to User’s Manual Figure A-1. Middle-of-the-Road EIA-232-D Configuration Figure A-2. Minimum EIA-232-D Connection Index NumericsIN-2 IN-3 Index

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