Viper 60s Theory Of Operation And Maintenance Manual page 6

VIPER SCSI 60, 125
&
150 THEORY OF OPERATION AND MAINTENANCE
Chapter 4
Interface .................................................................................................................................... 4-1
4.1 Overview.... ................................. .... .... ......... ....................................... .......................... ...... 4-1
4.1.1
ANSI SCSI Bus Standards.......... ............................................ ............. ....................
4-1
4.1.2
Signal Notation Conventions .................................................................................
4-1
4.2
SCSI Bus Connector Signals .............................................................................................
4-2
4.3
Signal Descriptions .. .... ........................ .... ............. .............. ..................... ..... ................. ....
4-3
4.4
Command Set Description.. ................. ........... ............................ ........... ................ ..........
4-4
4.5 SCSI Bus Protocol............... ........ ... ................. ....... ..................... ... ................... ....... ........... 4-5
4.6
Waiting and Control Phases .............................................................................................
4-6
4.6.1
Nonarbitrating Systems ...........................................................................................
4-6
4.6.2
Arbitrating Systems .................................................................................................
4-6
4.7
Selection and Reselection Phases .............................. ............................ ..........................
4-9
4.8
Information Transfer Phases ...........................................................................................
4-10
4.8.1
Asynchronous Data Transfer ................................................................................
4-10
4.8.1.1
Transfer from Target to Initiator .................................................................
4-11
4.8.1.2
Transfer from Initiator to Target .................................................................
4-12
4.9
Command Phase ...............................................................................................................
4-13
4.10
Data Phase ........................................................................................................................
4-13
4.10.1
Data-In Phase .........................................................................................................
4-13
4.10.2
Data-Out Phase ......................................................................................................
4-13
4.11
Status Phase .....................................................................................................................
4-13
4.12
Message Phase .................................................................................................................
4-13
4.12.1
Message-In Phase ..................................................................................................
4-13
4.12.2
Message-Out Phase ...............................................................................................
4-14
4.13
Con1mand Descriptor Block ..........................................................................................
4-14
4.14
SCSI Message Descriptions and Definitions ...............................................................
4-16
4.15
SCSI Status Code Descriptions and Definitions .........................................................
4-19
4.16
Attention Condition .......................................................................................................
4-21
4.17
Reset Condition ...............................................................................................................
4-21
4.18
Unit Attention Condition ..............................................................................................
4-21
4.19
Buffered Mode .................................................................................................................
4-22
4.20 Imn1ediate Function ....................................................................................................... 4-22
4.21
Residual Length Function .............................................................................................
4-22
4.22
Disconnect/Reconnect Function ..................................................................................
4-24
4.23
SCSI Memory Address Pointers ...................................................................................
4-25
4.23.1
Current Data Pointers ...........................................................................................
4-25
4.23.2
Saved Data Pointers ..............................................................................................
4-25
4.24 Early Warning Function ................................................................................................ 4-25
4.25
Error Reporting ...............................................................................................................
4-26
4.25.1
Soft Errors ...............................................................................................................
4-26
4.25.2
Hard Errors ............................................................................................................
4-26
4.26
SCSI Bus Phase Timing ..................................................................................................
4-26
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