Fujitsu 600C manual Bus signal drive conditions, 3Bus phases vs. signal drive sources 1/2

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4.2.3Bus signal drive conditions

SCSI devices drive signals of the SCSI bus. The types of SCSI devices are summarized in the following table, showing the signals that they can drive for each operating phase of the interface.

There are two kinds of signal driving methods, OR tied and NON-OR tied, as shown in Table 4.2. During an interface operating sequence. the BSY signal could be driven simultaneously by two or more SCSI units when the data bus is in the ARBITRATION or RESELECTION phase. This situation also occurs with the RST signs (Reset). These two signals must be ORtied. For other signals, either of the two methods may be used: further more, different drive methods may coexist for a signal on the bus.

Table 4-3Bus phases vs. signal drive sources (1/2)

Signal				C/D			DB7 to 0
Bus phase	BSY	SEL	'10	MSG	REQ	ACK	DBP	ATN	RST


BUSFREE	N	N	N	N	N	N	N	N	A

ARBITRATION	A	W	N	N	N	N	ID	N	A

SELECTION	I&T	I	N	N	N	I	I	I	A

RESELECTION	l&T	T	T	T	T	I	T	I	A

COMMAND	T	N	T	T	T	I	I	I	A

DATAIN	T	N	T	T	T	I	T	I	A

DATAOUT	T	N	T	T	T	I	I	I	A

STATUS	T	N	T	T	T	I	T	I	A

MESSAGE IN	T	N	T	T	T	I	T	I	A

MESSAGE OUT	T	N	T	T	T	I	I	I	A

N:The signal shall be released, since it is not being driven by any SCSI device.

A:The signal shall be driven by all SCSI devices that are actively arbitrating.

I:If driven, this signal be driven only by the active initiation

T:If the signal is driven, it shall be driven only by the active target.

W:The signal shall be driven by the one SCSI device that wins arbitration.

ID:	A unique data bit (the SCSI ID) shall be driven by each SCSI device that is actively arbitrating.
	The other seven data bits shall be released (shall not be driven) by this SCSI device. The parity bit
	(DB(P)) may be released or driven to the true state, but shall never be driven to the false state
	during this phase.
I&T:	The initiator and target drive the signal according to the interface operating sequence. The
	RESELECTION phase includes a sequence in which the initiator and target simultaneously drive
	the signal.

The signal shall be driven by the initiator, target, or both, as specified in the SELECTION phase and RESELECTION phase.

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Contents Version Page Table of Contents Diagnostics Group 3 error flowchart no paper in ADF paper tray Page General GeneralSystem Block Diagram Device Configuration Outer ViewComponents Functional Specifications Functional Specifications RemarksEnvironmental Specifications Environmental Specifications RemarksOperation Removing the Shipping BracketRemove the shipping retainer Fasten the shipping retainer Power On/Off Indication PanelSetting the Scsi ID and Connecting the Interface Cable Names and functions of the indicatorsScsi ID setting Name Color FunctionScsi Cable Connection Position Paper Specifications Paper SizePaper conditions 2.1 ADFFIatbed Items to avoidReadable area ADF readable areaDocument Setting Method When the document size is of letter/A4 size or smallerFlatbed When the document is a thick book Setting the ADF paper chute2 ADF Placing the documents on the ADF paper chute Placing the document on the ADF paper chuteAngling the document sheets Separating the sheets for easy feedingCleaning Cleaning the document cover and the document glassCleaning inside the ADF Page Interface ∙ Busy ∙ Check Condition ∙ Good ∙ Reservation Conflict Physical Specifications ConnectionPhysical Specification Specifications1SCSI physical specifications TerminationSignal Name Pin Number Pin assignmentsSystem configuration System configurationScsi Bus Addresses of Scsi devicesBus signals 2Bus signalsBus signal drive conditions 3Bus phases vs. signal drive sources 1/2Bus Phases Method of driving the interface signalOr connection Nonor connection 5Signal delay times definition Time Definition BUS Free phase Signal delay times definitionTime Definition Arbitration phase BSY Scsi SEL Selection phase Information Transfer phases Information Transfer phase type PhaseDB7 to 9,P Transfer Direction Asynchronous information transfer Asynchronous transfer from target to initiatorAsynchronous transler from initiator to target Commands Relative addressing is not supportedControl byte is not supported Reserve Unit command CommandsOperation Command Code hex Description Bit and field described as Reserved areReserve Unit command Command phase initiator Õ target TP third party ByteTpid third party device ID Byte Release Unit command Release Unit command Command phase initiator → targetTP third party Byte Inquiry command Inquiry command Command phase initiator → target10 Inquiry command Step Bus phase Initiator operation Target operationEvpd enable vital product data Byte Code ByteCAllocation length Byte Inquiry data Data in phase target → initiator AencSftRst Soft Reset Byte ADF mode Byte 24, bitColor mode Byte 24, bit 6 to ISO version, Ecma version, Ansi approved version ByteRequest Sense command Request Sense command Command phase initiator → target11 Request Sense command Sense data Data EN phase target → initiator Error code ByteAllocation length Byte Valid ByteILI incorrect length indicator Byte FM file mark ByteEOM end of medium Byte Sense key ByteSend Diagnostic command Command-specific information bytes Bytes 8 to BSense Additional Description Sense codeSend Diagnostic command Command phase initiator → target PF page format ByteSlftst selftest Byte Test Unit Ready command Contents of self-testResults of self-test Test Unit Ready command Command phase initiator → target AcknowledgmentSET Window command SET Window command Command phase initiator → targetWindow date Data OUT phase initiator → target Transfer Length Bytes 6 toHeader Window descriptor block Y resolution XR, YR Bytes 2 to 3 and 4 to Window identifier ByteAuto Byte Upper left X,YULX, ULY Bytes 6 to 9, a to DBrightness Byte RemarksBit per pixel Byte 1A RIF reverse image format Byte 1D, bitBit ordering Bytes 1E to 1F Halftone pattern Bytes lB to 1C lB reservedUpdate of ScanPartner 600C OEM manual 7.4 B&W Scanning Vender unique parametersCompression type, argument Bytes 20 to 18 Vender unique parameters byte 28 and laterPage Color Scanning Vender unique parameters 19 Vendor unique parameters byte 28 and laterADF Byte 2A, Bit Source Byte 2A, BitHighlight value Byte 2B Shadow value Byte 2CLine width Byte 2D to 2E Line count Byte 2F toObject Position command Object Position command Command phase initator → target Position type ByteBit Unload object Load objectCount Bytes 2 to NormalRead command Step Bus phase Initiator operation Target operationADF sequence Read command Command phase initiator → target Data type code ByteData type qualifier Bytes 4 to Transfer length TL Bytes 6 toData in phase target → initiator Image data Data Type Code =For binary data Pixel size data Data Type Code =Scan command Scan Command phase initiator → targetStatus Status phase target initiator Code Status of unitPhase ATN detection timing MessagesATN detection Command Complete X00 Message in phase target → initiator Message typesMessage Abort X06 Message OUT phase initiator → target Message Reject X07 Message IN/OUT phase initiator → targetATN detection phase Action No Operation X08 Message OUT phase initiator → target BUS Device Reset X0C Message OUT phase initiator → targetPhase when ATN is detected Action Message rejected ActionIdendify X80 to XFF Message OUT phase initiator → target Command Sequence Initial sequenceRead command sequence Read sequence for B&W modeRead sequence Single ReadMultiple Read Status Transition of Logical Unit Error Table Sense keyItems for Specifying Window Page Online diagnostics Ready LED Paper Jam LED Error indicationOnline diagnostics Offline diagnostics Offline diagnostics resultsDiagnostic flowcharts Group 1 error flowchart Lamp assemblyGroup 2 error flowchart Flatbed/ADF motor Group 3 error flowchart paper in ADF paper tray Group 3 error flowchart no paper in ADF paper tray