Priority | Seagate Ultra 320, Ultra 160 specs

Table 1:	SCSI IDs and associated SCSI bus arbitration priorities

SCSI	DB								DB	DB							DB	Priority
address	15								8	7							0	Priority
address	15								8	7							0


7	-	-		-	-	-	-	-	-	1	-	-	-	-	-	-	-	1

6	-	-		-	-	-	-	-	-	-	1	-	-	-	-	-	-	2

5	-	-		-	-	-	-	-	-	-	-	1	-	-	-	-	-	3

4	-	-		-	-	-	-	-	-	-	-	-	1	-	-	-	-	4

3	-	-		-	-	-	-	-	-	-	-	-	-	1	-	-	-	5

2	-	-		-	-	-	-	-	-	-	-	-	-	-	1	-	-	6

1	-	-		-	-	-	-	-	-	-	-	-	-	-	-	1	-	7

0	-	-		-	-	-	-	-	-	-	-	-	-	-	-	-	1	8

15	1	-		-	-	-	-	-	-	-	-	-	-	-	-	-	-	9

14	-	1		-	-	-	-	-	-	-	-	-	-	-	-	-	-	10

13	-	-		1	-	-	-	-	-	-	-	-	-	-	-	-	-	11

12	-	-		-	1	-	-	-	-	-	-	-	-	-	-	-	-	12

11	-	-		-	-	1	-	-	-	-	-	-	-	-	-	-	-	13

10	-	-		-	-	-	1	-	-	-	-	-	-	-	-	-	-	14

9	-	-		-	-	-	-	1	-	-	-	-	-	-	-	-	-	15

8	-	-		-	-	-	-	-	1	-	-	-	-	-	-	-	-	16

			Key: - = a logical 0 bit resulting from the data bus bit being released

The Host Adapter/Initiator must be identified by one of the 16 SCSI Device IDs (usually 7, which is highest arbi- tration priority). Make sure that none of the devices on the SCSI bus have duplicate IDs.

Certain SCSI bus functions are assigned to the initiator and certain SCSI bus functions are assigned to the tar- get. The initiator will select a particular target. The target will request the transfer of Command, Data, Status, or other information on the data bus.

Under SCSI-2 protocol, information transfers on the data bus are interlocked and follow a defined REQ/ACK Handshake protocol. One byte of information will be transferred with each handshake. Synchronous data transfers do not require a one-for-one interlocking of REQ/ACK signals, but the total number of REQ pulses in a particular data transfer event must equal the total number of ACK pulses. The synchronous data transfer option is described in Paragraphs 3.1.5.2 and 3.5.3.2 of the Ultra2 SCSI Interface Manual, part number 77738479.

This Ultra160/Ultra320 Parallel SCSI Interface Manual, discusses SCSI-3 protocol (now called only “SCSI”). There are now different ways of latching data from the REQ and ACK signals, depending on whether ST DATA phases, DT DATA phases, or paced transfers are being used for information transfers. This is described in Section 2.1.2.

The drive supports single initiator, single target; single initiator, multiple target; multiple initiator, single target; or multiple initiator, multiple target bus configurations.

14	Parallel SCSI Interface Product Manual, Rev. A )

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Seagate Ultra 320, Ultra 160 manual Scsi IDs and associated Scsi bus arbitration priorities, Priority

Contents

Parallel Scsi Interface Page Parallel Scsi Interface Page Revision status summary sheet Revision Date Writer/Engineer Parallel Scsi Interface Product Manual, Rev. a Table of Contents Parallel Scsi Interface Product Manual, Rev. a Logical characteristics Wide transfer Message system specification Scsi commands Miscellaneous Scsi bus characteristicsSPI information units Drive features List of Figures Xii Parallel Scsi Interface Product Manual, Rev. a How to use this interface manual Interface requirements Scope of Scsi standards General interface description Applicable standards Glossary Scsi client-server modelPage Page Page Page Page Page Keywords Summary of Scsi messages Physical interface characteristicsMessage Name Hex Code Number Scsi bus Scsi IDs and associated Scsi bus arbitration priorities Priority Scsi bus signals overview Pcrc signal usage requirements Scsi target usage of Pcrca Signal states Signal valuesSE signals LVD signals OR-tied signals Voltage and current definitions Signal sources Signal sourcesData bit P cable Data bit a cable I/O DB15-8 Scsi bus phase DB7-0 Scsi bus timing Scsi bus control timing values in nanosecondsTiming Reference Type Value ns Unless Timing description Scsi bus data and information phase ST timing values Timing values for negotiated transfer rateNanoseconds unless otherwise noted Timing values for negotiated transfer rate in nanosecondsPage ATN transmit setup time Min Receive Scsi bus data and information phase DT timing values Fast-160 Fast-320 Comments Total transmitter error budget Receiver errorsInterconnect and system margin ATN transmit setup time ATN receive setup timeCrosstalk time shift ISI of data Bus clear delay Bus free delayBus set delay Bus settle delay Flow control receive setup time Flow control transmit setup timePCRC receive setup time PCRC transmit setup time Data release delay Physical disconnection delayPower on to selection QAS arbitration delay Receive internal setup time Receive setup timeReceive internal hold time Receive negation period Reset delay Reset hold timeReset to selection Residual skew error System deskew delay Skew correction rangeStrobe offset tolerance System noise at launch Measurement points Clocking methods for data transfers LVD measurement points ST latching data vs. DT latching data Paced transfer on a Scsi bus DT synchronous transfer example Data transfer modes Asynchronous transfersSynchronous transfers Paced transfers ST Data phase parallel transfers DT Data phase parallel transfersData group transfers Information unit transfers Negotiation Negotiation algorithm When to negotiate Negotiable fieldsNegotiable fields and effects of successful negotiation Negotiation message pair Field name Response shall be Responding message requirementsField Name Message Numerically Transfer agreements Transfer period factor Transfer period factor relationshipsValue Description Message Transfer rate Synchronous 12.6 REQ/ACK offset Transfer width exponent Protocol options bits Protocol optionsIureq Bus phases resulting from Iureq changes Sdtr negotiation PPR negotiation setting Iureq to onePPR negotiation setting Iureq to zero PPR negotiation keeping Iureq set to zero Wrflow RdstrmRTI Retain Training Information Pcompen Transfer Negotiable field combinationsTransfer Period Message restrictions Negotiation message sequences Parallel Scsi Interface Product Manual, Rev. a BUS Free phase Scsi bus phases overviewUnexpected and expected bus free phases Expected bus free phases Arbitration and QAS overview Normal Arbitration phase QAS phase overview QAS protocol Selection phase Information unit transfers enabled Information unit transfers disabledSelection overview Selection using attention condition timeout procedure Reselection phase overview Reselection phasePhysical reconnection Physical reconnection timeout procedure Scsi bus fairness Information transfer phases Information transfer phasesSignal Phase Direction of transfer Comment Synchronous transfer Asynchronous transferST synchronous data transfer DT synchronous transfer Information unit transferPage Data group data field transfer Page Page Page Paced transfer Paced transfer training pattern Start of section a DT Data in phase training patternStart of section B DT Data OUT phase training pattern Start of section C 3.2 P1 data valid/invalid state transitions Starting pacing transfers at end of training pattern Starting pacing transfers with no training pattern Ending pacing transfers Paced information unit transfer Deskewing Wide transfer Command phase Data phase Status phase Message phase Signal restrictions between phases Message in phase exception condition handlingMessage OUT phase Message OUT phase exception condition handling Scsi bus phase sequences Scsi bus phase sequences overview Hard reset or protocol error Reselection Selection Arbitration DT Data Message OUT ST data bus protection using parity Parity checking rules for Selection and Reselection phasesData bus protection Data bus protection overview Error detection capabilities Order of bytes in the CRC field General message protocols and formats Message formats Message format One-byte messagesTwo-byte messages Extended messages Extended Message Codes Message categoriesLink Control Messages Link Control message codes Key Disconnect IdentifyIdentify message format Bit Byte Ignore Wide Residue Ignore Wide Residue message formatIgnore field definition Invalid data bits Initiator Detected Error Linked Command CompleteMessage Parity Error Message Reject Modify Data Pointer message format Modify Bidirectional Data Pointer Modify Bidirectional Data Pointer message format No Operation Parallel Protocol Request Parallel Protocol Request message format Value 00h 01h-FEh FFh Description Timing values Valid protocol options bit combinations Use ST Data in and ST Data OUT phases to transfer dataUse QAS for arbitration Parallel Protocol Request messages implied agreement QAS Request Restore PointersSave Data Pointers Synchronous Data Transfer Request Synchronous Data Transfer Request message format Sdtr messages implied agreements Initiator initiated Sdtr negotiation Target initiated Sdtr negotiationTask Complete Wide Data Transfer Request Wide Data Transfer Request message format Target initiated Wdtr negotiation Wdtr message implied agreementResponding Scsi device Wdtr response Implied agreement Task attribute messages Task attribute message overview and codes ACA Auto Contingent Allegiance Task attribute message codesACA message format Head of Queue Ordered Task management messages Task management message codes Task management message codesAbort Task 0Eh Logical Unit Reset Target ResetAbort Task SET Clear ACA Miscellaneous Scsi bus characteristics Bus reset condition Hard reset Reset events Asynchronous condition recovery Active pointers Saved pointers Asynchronous event notification Command processing considerations and exception conditionsIncorrect initiator connection Unexpected Reselection phase SPI information units Information unit transfer logical operationsPage Parallel Scsi Interface Product Manual, Rev. a 115 116 Parallel Scsi Interface Product Manual, Rev. a Parallel Scsi Interface Product Manual, Rev. a 117 SPI command information unit SPI information units SPI command information unit Bit Byte Task Attribute Codes Description Task Management flags Codes Description SPI LQ information unit SPI LQ information unit Bit Byte Bidi Direction SPI LQ information unit type Codes Type DescriptionF0H FFh AllPage SPI data stream information unit SPI data information unitSPI data information unit Bit Byte SPI status data stream information unit Bit Byte SPI status information unit Bit Byte SPI status information unitReserved Reserved for FCP SPI command information unit fields invalid Packetized Failures field Bit BytePacketized Failures code Codes Description Task management function not supportedPage 130 Parallel Scsi Interface Product Manual, Rev. a Command Descriptor Block CDB Command implementation requirementsReserved Page Fixed and variable length Command Descriptor Block formats Typical CDB for 16-byte commands Bit Byte Typical CDB for 12-byte commands Bit ByteAdditional CDB Data if required Typical variable length CDB Bit Byte Operation Code 7Fh Additional CDB Length n-7Page Naca a Control field Bit Byte LastLink b Status Status precedence Command examples Single command example Disconnect example Disconnect example Timing examples Auto Contingent Allegiance or Contingent Allegiance Overlapped commands Clearing an Auto Contingent Allegiance condition Sense data Incorrect logical unit selectionAsynchronous Event Reporting Autosense Unit Attention condition Target hard reset Logical unit resetQueued tasks formerly queued I/O processes Untagged task queuing Tagged task queuing Parameter rounding Programmable operating definition Incorrect initiator connection Default self-test S.M.A.R.T. systemSelf-test operations Short and extended self-tests Background mode Foreground modeSelf-test modes Exception commands for background self-tests Device type a Command Reference All device types Error detection for asynchronous information phases Self-test mode summaryProtection code Covered signals Word Location Signal MeaningPage Code description Error detection propertiesProtection code usage Error handling Protection code transmissionEnabling protection code checking Disabling protection code checking Case 1-Power off during removal or insertion SPI-3 to SCSI-2 terminology mapping SPI-3 to SCSI-2 terminology mappingSPI-3 equivalent term SCSI-2 term Index Code value reserved Disconnect privilege 148 domain 5, 9 dormant Initiator 3, 6, 14, 131, 140 faulted Multidrop 7 multimode Page Scsi Page Wdtr 40 170 Parallel Scsi Interface Product Manual, Rev. a Page Seagate Technology LLC