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Parallel SCSI Interface Product Manual, Rev. A )

2.12.6

REQ/ACK offset

The REQ/ACK OFFSET field determines the maximum number of REQs allowed to be outstanding before a
corresponding ACK is received at the SCSI target port during synchronous or paced transfers. For ST synchro-
nous transfers the REQ/ACK offset is the number of REQ assertions that may be sent by the SCSI target port
in advance of the number of ACK assertions received from the SCSI initiator port.

For DT synchronous transfers the REQ/ACK offset is the number of REQ transitions that may be sent by the
SCSI target port in advance of the number of ACK transitions received from the SCSI initiator port. For paced
transfers in DT DATA IN phase the REQ/ACK offset is the number of data valid state REQ assertions that may
be sent by the SCSI target port in advance of ACK assertions received from the SCSI initiator port.

For paced transfers in DT DATA OUT phase the REQ/ACK offset is the number of REQ assertions that may be
sent by the SCSI target port in advance of the number of data valid state ACK assertions received from the
SCSI initiator port.

See Section 2.9 for an explanation of the differences between ST and DT data transfers.

The REQ/ACK OFFSET value is chosen to prevent overflow conditions in the port’s receive buffer and offset
counter. The REQ/ACK OFFSET values and which timing values shall be selected are defined in Table 7.

Table 20 defines valid combinations of REQ/ACK OFFSET and other fields.

2.12.7

Transfer width exponent

The TRANSFER WIDTH EXPONENT field defines the transfer width to be used during DATA IN and DATA
OUT phases. The values are defined in Table 17.

If any of the protocol options bits other than QAS_REQ are set to one, then only wide transfer agreements are
valid. If all the protocol options bits other than QAS_REQ are set to zero, wide transfer agreements and narrow
transfer agreements are valid.

Table 20 defines valid combinations of TRANSFER WIDTH EXPONENT and other fields.

Table 16.

REQ/ACK Offset

Value

Description

Timing values

00h

Specifies asynchronous transfer agreement.

a

Asynchronous. (see Table 5)

01h - FEh Synchronous or paced transfers with specified offset.

Determined by transfer period factor
(see Table 14).

FFh

Synchronous or paced transfers with unlimited offset. Determined by transfer period factor

(see Table 14).

a

Transfer period factor and protocol options other than QAS_REQ shall be ignored.

Table 17:

Transfer width exponent

Value

Description

00h

Specifies 8-bit data bus (i.e., narrow transfer agreement)

01h

Specifies 16-bit data bus (i.e., wide transfer agreement)

02h

Obsolete

03h - FFh

Reserved

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Содержание Ultra 160

Страница 1: ...Parallel SCSI Interface Ultra 160 Ultra 320...

Страница 2: ......

Страница 3: ...Parallel SCSI Interface Ultra 160 Ultra 320...

Страница 4: ...aFONE SeaBOARD SeaTDD and the Wave logo are either registered trade marks or trademarks of Seagate Technology LLC Other product names are registered trade marks or trademarks of their owners Seagate r...

Страница 5: ...Parallel SCSI Interface Product Manual Rev A iii Revision status summary sheet Revision Date Writer Engineer Sheets Affected Rev A 03 27 06 C Chalupa G Houlder All...

Страница 6: ...iv Parallel SCSI Interface Product Manual Rev A...

Страница 7: ...lay 27 2 5 8 Cable skew delay 27 2 5 9 Chip noise in receiver 27 2 5 10 Clock jitter 27 2 5 11 Crosstalk time shift 27 2 5 12 De skewed data valid window 28 2 5 13 Flow control receive hold time 28 2...

Страница 8: ...period 32 2 5 59 Transmit setup time 33 2 5 60 Transmit REQ ACK period tolerance 33 2 5 61 Transmit REQ assertion period with P_CRCA transitioning 33 2 5 62 Transmit REQ negation period with P_CRCA t...

Страница 9: ...attention condition 57 3 2 1 2 1 Information unit transfers disabled or enabled 57 3 2 1 2 2 Selection without using attention condition time out procedure 57 3 3 RESELECTION phase 58 3 3 1 RESELECTIO...

Страница 10: ...ing attention condition with information unit transfers enabled 80 3 11 5 Phase sequences for physical selection using attention condition with information unit transfers enabled 81 3 12 Data bus prot...

Страница 11: ...108 5 3 Hard reset 108 5 4 Reset events 109 5 4 1 Bus reset event 109 5 4 2 Power on reset event 109 5 4 3 Target reset event 109 5 4 4 Transceiver mode change reset event 109 5 5 Asynchronous conditi...

Страница 12: ...51 8 2 Self test operations 151 8 2 1 Default self test 151 8 2 2 The short and extended self tests 151 8 2 3 Self test modes 152 8 2 3 1 Foreground mode 152 8 2 3 2 Background mode 152 8 2 3 3 Elemen...

Страница 13: ...disabled 79 Figure 11 Phase sequences for selection without using attention condition with information unit transfers disabled 79 Figure 12 Phase sequences for physical reconnection or selection witho...

Страница 14: ...xii Parallel SCSI Interface Product Manual Rev A...

Страница 15: ...ction 1 1 1 Note The individual drive s Product Manual has tables that specify which SCSI features the drive imple ments what the default parameters are for the various features they implement which p...

Страница 16: ...e rules to be followed by a SCSI initiator port when sending commands to a device Common Access Method Implementation standard which defines a host architecture and set of services for device access P...

Страница 17: ...us is given in individual drive s Product Manual The bus protocol supports multiple initiators disconnect reconnect additional messages plus 6 byte 10 byte 12 byte 16 byte and vari able length Command...

Страница 18: ...onous transfer An information transfer that uses the REQ ACK handshake with an offset of zero auto contingent allegiance ACA One of the conditions of a task set following the return of a CHECK CONDITI...

Страница 19: ...s transferring data or transfer ring command data to or from the initiator cyclic redundancy check CRC An error detecting code used to detect the validity of data that has been transferred during the...

Страница 20: ...rising this response are protocol specific hard reset a SCSI target port response to a reset event or a SCSI target port Reset in which the target per forms the operations described in Section 7 6 7 i...

Страница 21: ...nds executed by a single task which collectively make up a discrete I O operation In such a series each command has the same task identifier and all except the last have the link bit in the CDB contro...

Страница 22: ...dd pCRC field The portion of a data group that contains pCRC information pCRC protection The use of pCRC to detect DT DATA PHASE peer to peer protocol service A service used by an upper level protocol...

Страница 23: ...response from a SCSI device as described in Section 5 3 response A transaction conveying the result of a request SCSI application layer SAL The protocols and procedures that implement or invoke SCSI...

Страница 24: ...mmands A task consists of one initial connection and zero or more physical or logical reconnections all per taining to the task task abort event An event or condition indicating that the task has been...

Страница 25: ...his standard invalid A keyword used to describe an illegal or unsupported bit byte word field or code value Receipt of an invalid bit byte word field or code value shall be reported as an error mandat...

Страница 26: ...WIDE RESIDUE 23 88 INITIATE RECOVERY 0F Not described in this manual INITIATOR DETECTED ERROR 05 89 MESSAGE PARITY ERROR 09 89 MESSAGE REJECT 07 89 MODIFY DATA POINTER 01 05 00 89 extended message NO...

Страница 27: ...is assigned by installing 0 3 jumper plugs onto a connector in a binary coded configuration during system configuration Some drive models have an interface that includes the SCSI bus ID lines so that...

Страница 28: ...EQ 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...

Страница 29: ...sourced by a SCSI target port to control the direction of data movement on the Data Bus with respect to a SCSI initiator port Assertion indicates input to the initiator This signal also distin guishe...

Страница 30: ...s driven such that the number of logical ones in the byte plus the P1 bit is odd During the ST DATA PHASE with transfer length set for 8 bit transfers COMMAND PHASE MESSAGE PHASE and STATUS phase the...

Страница 31: ...ader LC model drives 80 pin direct connect I O connector can be assigned their bus ID over the SCSI interface 2 1 2 Signal values Signals may assume true or false values There are two methods of drivi...

Страница 32: ...ense Note For a description of VBIAS see Section 7 3 1 of ANSI specification SPI 5 T10 1525D 2 3 OR tied signals The BSY SEL and RST signals shall be OR tied BSY and RST signals may be simultaneously...

Страница 33: ...ECTION PHASE Init If driven this signal shall be driven only by the active initiator None The signal shall be released that is not driven by any SCSI device The bias circuitry of the bus termi nators...

Страница 34: ...datory Timing description Reference Type Timing value ns unless noted Arbitration delay 2 5 1 minimum 2 4 s Bus clear delay 2 5 4 maximum 800 Bus free delay 2 5 5 minimum 800 Bus set delay 2 5 6 maxim...

Страница 35: ...25 ATN receive setup time 2 5 3 min 45 17 17 8 5 6 75 Cable skew 2 2 5 8 max 4 0 4 0 4 0 3 0 2 5 Receive assertion period 3 2 5 30 min N A 70 22 11 6 5 Receive hold time 3 4 2 5 31 min N A 25 25 11 5...

Страница 36: ...ved skew 3 Calculated assuming timing budget shown in Table 9 4 Measured at the receiver terminal using clean input signals with 500 mV peak amplitude and 1 ns rise and fall time between 20 and 80 of...

Страница 37: ...t 40 Fast 80 Fast 160 Fast 320 ATN transmit setup time 2 5 2 min 48 4 29 2 19 6 14 8 14 14 Flow control transmit hold time 2 5 15 min 38 4 19 2 9 6 4 8 14 14 Flow control transmit setup time 2 5 16 mi...

Страница 38: ...7 8 4 9 3 45 3 0 3 0 Flow control receive hold time 2 5 13 min 11 6 5 8 2 9 1 45 3 0 3 0 Flow control receive setup time 2 5 14 min 18 6 12 8 9 9 8 45 3 0 3 0 pCRC receive hold time 2 5 17 min 11 6 5...

Страница 39: ...noise at receiver 0 25 0 25 0 2 0 2 Time impact Chip noise in receiver 0 2 0 2 0 2 0 2 Time impact Receiver chip skew 0 75 0 0 75 0 Receiver trace skew 0 2 0 0 2 0 Receiver time asymmetry 0 35 0 35 0...

Страница 40: ...signal corresponding to the last iuCRC transfer of an information unit Specified to provide the increased ATN receive setup time subject to intersymbol interference cable skew and other distortions 2...

Страница 41: ...detect BUS FREE phase it shall release all SCSI bus signals within a bus clear delay minus the excess time 2 5 5 Bus free delay The minimum time that a SCSI device shall wait from its detection of th...

Страница 42: ...e P_CRCA signal Specified to pro vide the increased P_CRCA receive setup time subject to intersymbol interference cable skew and other dis tortions 2 5 16 Flow control transmit setup time The minimum...

Страница 43: ...ee Section 4 3 12 2 5 27 QAS assertion delay The maximum time allowed for a SCSI device to assert certain signals during QAS 2 5 28 QAS release delay The maximum time allowed for a SCSI device to rele...

Страница 44: ...ta transfers the minimum time required at the receiving SCSI device between the changing of Data Bus DB P_CRCA and or DB P1 signals and the assertion of the REQ signal or the ACK signal while using sy...

Страница 45: ...et to selection The recommended maximum time from after a reset condition until a SCSI target is able to respond with appro priate status and sense data to the TEST UNIT READY INQUIRY and REQUEST SENS...

Страница 46: ...bus signals caused by system noise at the receiver e g noise caused by current changes in the voice coil measured at the receiving SCSI device connector not including the time shift from the system n...

Страница 47: ...sed receive REQ negation period subject to loss on the inter connect 2 5 63 Transmitter skew The maximum difference in time allowed between the rising or falling edge of a 1010 pattern on the DATA BUS...

Страница 48: ...ed in Section 9 Figure 62 of SPI 5 for the measurement of the timing values The rise and fall times for the LVD REQ ACK signals shall be nominally the same as for the LVD Data P_CRCA and DP 1 signals...

Страница 49: ...atch the synchronous transfers DT Data shown in Figure 5 For paced transfers the clocking signal i e REQ or ACK may occur when the data bus is changing state Figure 5 ST latching data vs DT latching d...

Страница 50: ...eceiver clock shifting and an optional receiver signal adjustment In addition the drive precompensation may be switched out of the data path at the request of the receiving SCSI device REQ or ACK DT D...

Страница 51: ...Paced This section provides a brief description of each of these types of transfer modes 2 9 1 Asynchronous transfers SCSI device ports default to 8 bit asynchronous transfers 8 bit asynchronous trans...

Страница 52: ...of the number of bytes in the data field the pCRC field shall be the last four bytes of the data group The value of the pad bytes within the pad field is vendor specific During DT DATA IN phase if th...

Страница 53: ...control is part of the negotiated transfer agreement between two SCSI devices i e the WR_FLOW bit set to one 2 12 Negotiation PARALLEL PROTOCOL REQUEST PPR see Section 4 3 12 SYNCHRONOUS DATA TRANSFE...

Страница 54: ...i ation Negotiation should not be originated after every selection and reselection as this may impact perfor mance Note SCSI target ports may have had their support for originating negotiation after p...

Страница 55: ...Sets to 00h QAS_REQ Negotiated Sets to 00h Sets to 00h DT_REQ Negotiated Sets to 00h Sets to 00h IU_REQ Negotiated Sets to 00h Sets to 00h Table 12 Responding message requirements Field Name Message...

Страница 56: ...IU_REQ QAS_REQ All other protocol options Default 00h Any 00h 0 0 0 0 Asynchronous 00h Any Any 0 0 Any 0 Synchronous GE 01h GE 09h Any Any Any Any Any ST synchronous GE 01h GE 0Ah Any 0 0 Any Any DT s...

Страница 57: ...ndicated transfer factor is selected Table 20 defines valid combinations of TRANSFER PERIOD FACTOR and other fields Table 14 Transfer period factor Value Description Message Transfer rate 00h 06h Rese...

Страница 58: ...e REQ ACK OFFSET value is chosen to prevent overflow conditions in the port s receive buffer and offset counter The REQ ACK OFFSET values and which timing values shall be selected are defined in Table...

Страница 59: ...hall maintain a bus free required flag Each time a negotiation is successful that results in the IU_REQ bit being changed from the previous agreement i e zero to one or one to zero the SCSI target por...

Страница 60: ...negotiated with each other to disable QAS neither port shall participate in QAS arbitrations when attempting to connect to the other port When QAS and information unit transfers are both enabled for a...

Страница 61: ...t need to retrain on each connection In response the SCSI target port shall set RTI to one if it is capable of saving paced data transfer training information and zero if it is not The SCSI initiator...

Страница 62: ...ations 0Ah FFh 01h FFh 00h or 01h 0 0 0 0 0 1 0 0 Use ST DATA IN and ST DATA OUT phases to transfer data with synchronous transfers and participate in QAS arbitrations 09h FFh 01h FFh 01h 0 0 0 or 1 0...

Страница 63: ...SCSI target port originated WDTR negotiation occurs a BUS FREE phase generated because the SCSI target port detected that IU_REQ was changed is indistinguishable from a BUS FREE phase generated becau...

Страница 64: ...50 Parallel SCSI Interface Product Manual Rev A...

Страница 65: ...evices shall release all SCSI bus signals within one bus clear delay after BSY and SEL are continuously negated false for one bus settle delay If a SCSI device requires more than one bus settle delay...

Страница 66: ...1 1 2 The target uses an unexpected bus free to inform the initiator of a protocol error The target may switch to a BUS FREE phase at any time except during an ARBITRATION phase independent of any att...

Страница 67: ...o participate in arbitration when competing with faster SCSI devices and may not be ensured fair arbitration by the arbitration fairness algorithm 4 After waiting at least one arbitration delay measur...

Страница 68: ...possible for the SCSI devices that have QAS enabled to prevent SCSI devices that do not have QAS enabled from arbi trating for the bus This occurs when SCSI devices that have QAS enabled never go to...

Страница 69: ...not arbitrate until its fairness register is cleared 4 After waiting at least one QAS arbitration delay measured from the detection of the MSG C D and I O signals being negated the SCSI device shall e...

Страница 70: ...selected target may examine the Data Bus in order to determine the SCSI ID of the selecting initiator The selected target shall then assert the BSY signal within one selection abort time of its most...

Страница 71: ...ll detect it is selected when the SEL signal and its SCSI ID bit are true and the BSY and I O sig nals are false for at least one bus settle delay The selected target may examine the Data Bus in order...

Страница 72: ...g the QAS phase The SCSI device that won the arbitration identifies itself as a SCSI target port by asserting the I O signal The winning SCSI device shall also set the Data Bus to a value that is the...

Страница 73: ...e where the initiator aborted an outstanding command thus removing the need to re arbitrate When a SCSI device does not need to arbitrate for the SCSI bus it shall monitor the arbitration attempts of...

Страница 74: ...ndshake and remain valid until after the negation of the ACK signal at the end of the handshake of the last transfer of the phase The SCSI target port shall not transition into an information transfer...

Страница 75: ...K signal becomes true at the target the target shall read the DB 7 0 P_CRCA or DB 15 0 P_CRCA P1 signals then negate the REQ signal When the REQ signal becomes false at the initiator the initiator may...

Страница 76: ...ion of the REQ or ACK signal The REQ ACK offset specifies the maximum number of REQ transitions that shall be sent by the target in advance of the number of ACK transitions received from the initiator...

Страница 77: ...phase and the initiator shall send a SCSI initiator port Detected Error message see Section 4 3 5 or an ABORT TASK message to the target These messages notify the target that the SPI status informatio...

Страница 78: ...target shall change to a DT DATA IN phase and transmit a SPI status information unit with a RSPVALID bit of one and the packetized failure code set to Invalid Type Code Received in SPI L_Q Informatio...

Страница 79: ...e DB 15 0 signals to their pad values 3 wait at least the longer of one pCRC transmit setup time from the assertion of P_CRCA or one transmit setup time from DB 15 0 being driven with valid pad data 4...

Страница 80: ...egation After either of the above sequences is complete the target has ended a data group transfer The initiator shall read the value on the DB 15 0 signals within one receive hold time of the transit...

Страница 81: ...f one transmit assertion period 10 drive the DB 15 0 signals to their pCRC values 11 delay at least one transmit setup time 12 negate the ACK signal and 13 hold the DB 15 0 signals valid for a minimum...

Страница 82: ...the originating SCSI device the originating SCSI device shall apply driver precompensation to all the data signals the P_CRCA sig nal the P1 signal and the REQ and or ACK signal For paced DT DATA IN p...

Страница 83: ...s A B and C Each section contains a different pattern that may be used to train circuits within a receiver 3 5 3 1 1 DT DATA IN phase training pattern The SCSI target port shall indicate a training pa...

Страница 84: ...ning pattern the SCSI target port continues asserting and negating the REQ signal at the negotiated transfer period e g 6 25 ns transfer period at Fast 160 and the P1 signal at twice the nego tiated t...

Страница 85: ...gnals negated for the equivalent of 8 additional transfer periods 4 simultaneously assert and negate PA and DB 15 0 signals at twice the negotiated transfer period i e simultaneously repeat a 1100b bi...

Страница 86: ...SEL signal is negated before the first assertion of the REQ signal The DT DATA IN phase without training starts on the first assertion of REQ if the SEL is not asserted The SCSI target port shall beg...

Страница 87: ...at least a bus settle delay plus a data release delay before asserting REQ and shall ignore any ACK transitions for at least a bus settle delay plus a data release delay after transitioning the C D I...

Страница 88: ...an even number of transfers the REQ and ACK signals are negated both before and after the transmission of the SPI information unit Paced information unit transfers exception handling conditions are de...

Страница 89: ...d it may retry the command by switching to the MESSAGE IN phase and sending a RESTORE POINTERS message The target shall then switch to the COMMAND phase to receive the original command If the target d...

Страница 90: ...able SCSI initiator port shall wait a minimum of one QAS non data phase REQ ACK period to assert ACK after detecting the assertion of REQ A QAS capable SCSI initiator port shall assert ACK for a minim...

Страница 91: ...ransferring at least one byte The target may also indicate that it has successfully received the message bytes by changing to the BUS FREE phase e g after receiving ABORT TASK SET or TARGET RESET mess...

Страница 92: ...ne system deskew delay after asserting the C D signal The initiator shall negate the DB P_CRCA signal no sooner than one system deskew delay after the detection of the assertion of the C D signal f Th...

Страница 93: ...ement is not in effect shall be as shown in Figure 12 The normal progression for selection without using attention condition see Section 3 2 1 1 2 is 1 from the BUS FREE phase to ARBITRATION 2 from AR...

Страница 94: ...ut using attention condition see Section 3 2 1 1 3 if QAS is dis abled is 1 from the BUS FREE phase to ARBITRATION 2 from ARBITRATION to SELECTION or RESELECTION 3 from SELECTION or RESELECTION to one...

Страница 95: ...n 3 12 1 Data bus protection overview The data bus DB P_CRCA signal and the DB P1 signals are used to generate parity or control the transfer of pCRC information on the Data Bus 3 12 2 ST data bus pro...

Страница 96: ...rity protection is not enabled during DT DATA phases 3 12 3 DT data bus protection using CRC 3 12 3 1 DT data bus protection using CRC overview When pCRC protection or iuCRC protection are enabled the...

Страница 97: ...e then more messages may follow The IDENTIFY message establishes a logical connection between the SCSI initiator port and the specified logical unit within the SCSI target device known as an I_T_L nex...

Страница 98: ...consecutive MESSAGE IN phases or consecutive MESSAGE OUT phases See sections refer enced in Table 26 for details of the extended messages Table 25 Extended message format 1 The EXTENDED MESSAGE LENGTH...

Страница 99: ...s Code Extended message 00h MODIFY DATA POINTERS 01h SYNCHRONOUS DATA TRANSFER REQUEST 02h Reserved 03h WIDE DATA TRANSFER REQUEST 04h PARALLEL PROTOCOL REQUEST 05h MODIFY BIDIRECTIONAL DATA POINTER 0...

Страница 100: ...plicable Init SCSI initiator port Targ SCSI target port 80h Codes 80h through FFh are used for IDENTIFY messages Note The clear attention condition only applies during MESSAGE OUT phase 55h NS O O O Q...

Страница 101: ...n unit transfer agreement is in effect regardless of the QAS mode do a physical disconnect by releasing BSY After releasing the BSY signal the target shall not participate in another ARBITRATION phase...

Страница 102: ...ring of the IDEN TIFY and TASK ATTRIBUTE messages See Section 3 9 3 1 for handling target detected errors during the MESSAGE OUT phase Identification is considered successful during a target s physica...

Страница 103: ...attempts a retry after receiving the MESSAGE PARITY ERROR message the target shall return to the MESSAGE IN phase before switching to some other phase the target shall resend the entire message that h...

Страница 104: ...ded using two s complement arithmetic to the value of the current data in pointer The ENABLE MODIFY DATA POINTER EMDP bit in the Disconnect reconnect mode page indicates whether the target is permitte...

Страница 105: ...ave any other valid message to send For example if the target does not respond to the attention condition until a later phase and at that time the original message is no longer valid the initiator may...

Страница 106: ...period equals the period factor x 4 Fast 10 data is latched using a transfer period of less than or equal to 196 ns and greater than or equal to 100 ns 32h FFh Transfer period equals the period factor...

Страница 107: ...roup transfers shall be enabled when received from the initiator and that information unit transfers are disabled when received from the target An IU_REQ bit of one indicates that information unit tra...

Страница 108: ...ever it is appropriate to negotiate a data transfer agreement SCSI devices that are currently capable of supporting any of the Parallel Protocol Request options shall not respond to a PARALLEL PROTOCO...

Страница 109: ...t shall respond with a PARALLEL PROTOCOL REQUEST message or a MESSAGE REJECT message Target s Parallel Protocol Request response Implied agreement Non zero REQ ACK OFFSET Synchronous transfer i e each...

Страница 110: ...be negated by both SCSI devices In this case both SCSI devices shall use the eight bit asynchronous data transfer mode with all the protocol options bits set zero to indicate ST DATA IN and ST DATA O...

Страница 111: ...s are negotiated for each pair of SCSI devices The synchronous data transfer agreement only applies to DATA phases An SDTR message exchange shall be initiated by a SCSI device whenever a previously ar...

Страница 112: ...res a larger transfer period a smaller REQ ACK offset or both in order to receive data successfully it substitutes values in its SDTR message as required returning unchanged any value not required to...

Страница 113: ...two SCSI devices 4 3 16 2 Initiator initiated SDTR negotiation If the initiator recognizes that SDTR negotiation is required it creates an attention condition and sends a SDTR message to begin the neg...

Страница 114: ...eement in an indeterminate state such as a after a hard reset b after a TARGET RESET message c after a power cycle and d after a change in the transceiver mode e g LVD mode to MSE mode Any condition t...

Страница 115: ...respond with its WDTR message MESSAGE PARITY ERROR message or with a MESSAGE REJECT message If an abnormal condition prevents the initiator from responding with a WDTR message or with a MESSAGE REJECT...

Страница 116: ...between the two devices 4 4 Task attribute messages Two byte task attribute messages are used to specify an identifier called a tag for a task that establishes the I_T_L_Q nexus The Task Attribute mes...

Страница 117: ...del 2 standard for the task set management rules Table 40 Task attribute message codes Key M Mandatory support O Optional support Q Mandatory if tagged queuing is implemented In Target to initiator Ou...

Страница 118: ...ecifies that the task shall be placed in the task set as an Ordered task The rules used by the task manager to handle Ordered tasks within a task set are defined in Section 7 0 of this manual and in t...

Страница 119: ...ote The ABORT TASK message in the case of only an I_T nexus is useful to an initiator that is not able to get an Identify message through to the target due to parity errors and just needs to end the c...

Страница 120: ...ge The target shall then continue processing the task that was in process when the CLEAR ACA message was received On receipt of a CLEAR ACA message the task manager in addition to clearing the ACA con...

Страница 121: ...ATN signal at least two system deskew delays before asserting the target s ID in the bus To create an attention condition during an information transfer phase the initiator shall assert the ATN signal...

Страница 122: ...mation units the target shall enter MESSAGE OUT phase at the completion of the next SPI information unit During a RESELECTION phase the initiator should only create an attention condition to transmit...

Страница 123: ...either Bus Device Reset Function Occurred or Power On Reset or Bus Device Reset Occurred 5 4 4 Transceiver mode change reset event When a SCSI device that contains multimode transceivers detects a tr...

Страница 124: ...side for data associated with the current task See Section 4 3 14 for a detailed description of operations resulting from the RESTORE POINTERS message 5 5 3 Saved pointers Saved pointers point to init...

Страница 125: ...t information See SYNCHRONOUS DATA TRANSFER REQUEST message Section 4 3 16 for examples of these events Each SCSI device that returns processor device type with an AERC bit of one shall be issued a TE...

Страница 126: ...ror and if not detected could result in a task operating with a wrong set of pointers This is considered a catastrophic failure on the part of the initiator Therefore vendor specific error recovery pr...

Страница 127: ...pt the current task for the initiator participating in the negotiation and the SCSI initiator shall abort all tasks except the current task for the target device When an information unit transfer agre...

Страница 128: ...al connection This occurs when a SCSI initiator port uses the multiple command option in the SPI L_Q information unit For each SPI L_Q received with a multiple command type or a last command type a lo...

Страница 129: ...rmation unit 3 See Figure 16 4 See Figure 18 Figure 15 SPI information unit sequence during initial connection SPI L_Q always Init to Targ logical connect DT DATA OUT SELECTION SPI COMMAND always Init...

Страница 130: ...information unit sequence during data type transfers SPI L_Q always Targ to Init logical reconnect DT DATA IN from SPI STATUS or SPI DATA DT DATA OUT from SPI COMMAND or SPI DATA DT DATA IN DT DATA OU...

Страница 131: ...rmation unit sequence during data stream type transfers SPI L_Q always Targ to Init logical reconnect DT DATA IN from SPI STATUS or SPI DATA DT DATA OUT from SPI COMMAND or SPI DATA DT DATA IN DT DATA...

Страница 132: ...d the Task Man agement Flags field equals 00h the target shall transfer all the bytes of the current SPI command information unit but need not hold the transmitted information After transferring all t...

Страница 133: ...the task with a Good status The packetized failure code shall be set to task man agement function failed If the target terminates a SPI L_Q SPI command information unit pair for one of the following...

Страница 134: ...ests that the task be managed according to the rules for head of queue task attribute See the SCSI Architecture Model 4 standard 010b Requests that the task be managed according to the rules for an or...

Страница 135: ...rface SPI 5 6 2 2 SPI L_Q information unit The SPI L_Q information unit see Table 49 contains L_Q nexus Logical unit Q tag relationship information for the information unit that follows the type of in...

Страница 136: ...initiator shall follow the procedures defined in Section 3 5 2 2 1 1 If a SCSI target port receives a type code that is not defined in Table 50 that target shall follow the procedures defined in Sec t...

Страница 137: ...ta Length field shall be greater than or equal to 14h and less than or equal to 90h The iuCRC Interval field shall be set to zero and ignored by the target device The Bidi Direction field shall be set...

Страница 138: ...d The iuCRC interval length shall not include the 4 byte iuCRC nor any transmitted pad bytes e g an iuCRC interval length of 510 transfer 510 bytes of data plus 2 bytes of pad plus 4 bytes of iuCRC fo...

Страница 139: ...SPI L_Q information unit If the data transfer size is not a multiple of the data length the SCSI target shall end the stream at a data length boundary and shall send a new SPI L_Q with a smaller data...

Страница 140: ...quivalent to the initiator receiving a DISCONNECT message To end a sequence of SPI data stream information units a SCSI initiator may request a disconnect by estab lishing an attention condition The i...

Страница 141: ...the sense data list length shall be ignored and no sense data is provided A SNSVALID bit of one indicates the Sense Data List Length field specifies the number of bytes in the Sense Data field 3 If se...

Страница 142: ...he iuCRC field shall use the algorithm defined in Subsection 11 3 ANSI SCSI Parallel Interface SPI 5 T10 1525D The Packetized Failures field see Table 55 contains information describing the packetized...

Страница 143: ...Parallel SCSI Interface Product Manual Rev A 129 The iuCRC field shall use the algorithm defined in Subsection 11 3 ANSI SCSI Parallel Interface SPI 5 T10 1525D...

Страница 144: ...130 Parallel SCSI Interface Product Manual Rev A...

Страница 145: ...ent to request the automatic return of sense data Fibre Channel protocol already has this feature in its packetized command structure 7 1 Command implementation requirements The first byte of any SCSI...

Страница 146: ...This is fol lowed by command parameters if any and a control field For all commands if there is an invalid parameter in the Command Descriptor Block the drive shall terminate the command without alter...

Страница 147: ...shows the typical format for a variable length CDB Table 57 Typical CDB for 6 byte commands See notes following Table 61 Table 58 Typical CDB for 10 byte commands See notes following Table 61 Bit Byte...

Страница 148: ...erved SERVICE ACTION if required 2 2 MSB LOGICAL BLOCK ADDRESS if required 3 3 4 5 LSB 6 MSB TRANSFER LENGTH If required 4 PARAMETER LIST LENGTH if required 5 ALLOCATION LENGTH if required 6 7 8 9 LSB...

Страница 149: ...general command func tion specified in the Operation Code field While the Service Action field is defined for typical CDB formats it is used as described in this clause only in those CDB formats that...

Страница 150: ...I initiator port is called the Allocation Length The Allocation Length speci fies the number of bytes that the initiator has allocated for returned data The drive shall terminate the DATA IN phase whe...

Страница 151: ...a sense key of ILLEGAL REQUEST if the Link bit is set to one and the drive does not support linked commands c Obsolete bit Bit 0 provides an obsolete way to request interrupts between linked commands...

Страница 152: ...cates that the Device Server has successfully completed the task Check Condition This status indicates that an auto contingent allegiance or contingent allegiance condition has occurred see Section 7...

Страница 153: ...31 D Task Set Full This status shall be implemented if the logical unit supports the creation of tagged tasks see Section 7 7 This status shall not be implemented if the logical unit does not support...

Страница 154: ...ointers The initiator sets up the active pointers for the operation requested arbitrates for the SCSI bus and selects the drive Once this pro cess is completed the drive assumes control of the operati...

Страница 155: ...the initiator the initiator restores the pointers to their most recently saved values which in this case are the initial values and the drive continues as in the single command example to finish the o...

Страница 156: ...initiator becomes aware of the condition After sending status and a service response of Task Complete the logical unit shall modify the state of all tasks in the faulted task set as described in SCSI...

Страница 157: ...e cleared a As the result of a power on or a logical unit reset see ANSI SAM 4 document T10 1683 D b Through a Clear ACA task management function issued by the faulting initiator as described in ANSI...

Страница 158: ...to REQUEST SENSE the target shall return sense data The target s response to any command other than INQUIRY and REQUEST SENSE is vendor specific or d The target supports the logical unit but is incap...

Страница 159: ...nditions described below The return of sense data in this way is equivalent to an explicit command from the application client requesting sense data immediately after being notified that an ACA condit...

Страница 160: ...another unit attention condition may exist for example a power on condition followed by a microcode change condition The Unit Attention condition for a particular initiator is cleared when that initi...

Страница 161: ...values have been established Mode select conditions for which no saved values have been established shall be returned to their default values e Set a Unit Attention condition see Section 7 6 6 and f...

Страница 162: ...ask Queue Tag messages are used the drive executes the commands in the order received with respect to other commands received with Ordered Task Queue Tag messages All commands received with a Simple T...

Страница 163: ...is explicitly specified in the description of the parameter 7 9 Programmable operating definition Some applications require that the operating definition of a logical unit be modified to meet the spe...

Страница 164: ...incorrect initiator connection also occurs on an initial connection when a SCSI initiator port a attempts to establish an I T L Q nexus when an I T L nexus already exists from a previous connection o...

Страница 165: ...f the test is successful or a CHECK CONDITION status if the test fails 8 2 2 The short and extended self tests There are two optional types of self test that may be invoked using the Self Test Code fi...

Страница 166: ...a self test in the foreground mode An application client may terminate a self test that is being performed in the foreground mode using an Abort Task ABORT TASK SET or Clear Task Set task management...

Страница 167: ...the application client at any time dur ing execution of a self test to poll the logical unit s progress While executing a self test unless an error has occurred a device server shall respond to a REQ...

Страница 168: ...are the covered signals to be encoded and details of the protection code to be used on the asyn chronous information phases Mode When status is returned How to abort the self test Processing of subse...

Страница 169: ...tion code A sequence of consecutive information transfers during a Message Command or STATUS phase is a run The Sequence ID increments during a run A new run begins on every phase change or on each Me...

Страница 170: ...being set to zero for the fifth word transferred and so forth until the run is complete At the beginning of the next run the Sequence ID is set to zero again The Sequence ID provides detection of err...

Страница 171: ...word bits 0 1 4 6 8 9 10 11 and 12 Redundant bit 3 is the XOR of code word bits 1 2 5 7 9 10 11 12 and 13 Redundant bit 4 is the XOR of code word bits 2 3 6 8 10 11 12 13 and 14 Redundant bit 5 is th...

Страница 172: ...SCSI device disables protection code checking when it detects that no protection code data is being transmitted on the upper byte The determination that no protection code data is being transmitted i...

Страница 173: ...all employ transceivers that conform to the applicable requirements in ANSI SPI 5 specification T10 1525D sections 7 2 2 and 7 3 5 3 for glitch free power ing on and off The SCSI device shall maintain...

Страница 174: ...ms b and c above are met f The SCSI bus termination shall be external to the SCSI device being inserted or removed g Initiation or resumption of I O processes for a newly inserted or removed SCSI devi...

Страница 175: ...bus signal 15 transmit setup time 26 attention condition 107 attribute 142 auto contingent allegiance 4 6 137 142 144 active 139 142 attribute 143 condition 4 146 message 103 NACA 1 145 task 142 autos...

Страница 176: ...ACA 0 145 contingent allegiance condition 6 143 control byte 142 143 control field 136 control mode page 5 143 148 control data SCSI bus signal 15 covered signal 155 CRC 82 CRC protection 1 CRC see cy...

Страница 177: ...0 21 24 34 43 faulted initiator 6 faulted task 142 fibre channel protocol 131 field maximum value 149 minimum value 149 reserved 131 flow control receive hold time 28 flow control receive setup time 2...

Страница 178: ...ink control message 85 linked CDB 7 linked command 6 7 140 148 complete 137 logical characteristics 51 logical connect 7 113 logical disconnect 7 113 logical reconnect 7 113 logical unit 5 7 option 7...

Страница 179: ...nd of training pattern 72 with no training pattern 72 packetized 8 command structure 131 Packetized Failures SPI status information unit 127 128 Packetized Failures List Length SPI status information...

Страница 180: ...receive internal setup time 30 receive negation period 30 receive REQ ACK period tolerance 30 receive REQ assertion 30 receive REQ negation period 30 receive SCSI bus data and information phase DT tim...

Страница 181: ...mation unit 128 sense data 144 Sense Data List SPI status information unit 127 Sense Data List Length SPI status information unit 127 Sense Data Valid SPI status information unit 127 sense key 131 144...

Страница 182: ...equest 10 management response 10 manager 10 pending 8 queue tag message 148 queued 147 slot 10 tag 10 Task Attribute SPI command information unit 119 task attribute message 102 task attributes 6 task...

Страница 183: ...ters page 146 unit attention parameters 146 unit attention sense key 146 unlinked command 11 untagged command 149 untagged task 143 address 10 queuing 147 upper level protocol 8 11 upper level protoco...

Страница 184: ...170 Parallel SCSI Interface Product Manual Rev A...

Страница 185: ......

Страница 186: ...Seagate Technology LLC 920 Disc Drive Scotts Valley California 95066 4544 USA Publication Number 100293069 Rev A Printed in USA...

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