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Emerson MVME147 manual Notes

Models: MVME147

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CUSTOM SCSI PACKETS

NOTES:	1.	Refer to Chapter 3.
	2.	Command Table = 384 bytes
		RAM work area.

This first class is used for command execution and/or message passing through the MVME147 SCSI firmware while the module is playing the initiator role. According to SCSI definition, an initiator is a SCSI device (usually a host system) which requests an operation to be performed by another SCSI device; a TARGET is a SCSI device which performs an operation requested by an initiator. Initiator role custom packets request operations to be performed by other SCSI devices. For the initiator role, certain data structures are needed by the SCSI firmware. These are:

1.SCRIPT: A "script" is a sequence of SCSI bus phases that the initiator expects the TARGET to perform when executing a requested command. For example, a disk read (under SCSI rules) would typically require the following SCSI bus phases:

MESSAGE-OUT: The IDENTIFY message is sent from the initiator to the TARGET. This message contains the identification of the desired logical unit of the selected disk controller that the initiator wishes to read. The message also indicates whether the initiator is capable of reselection.

COMMAND: The Command Descriptor Block (CDB) is sent during the command phase to specify the block number to read, the logical unit to read from, the number of blocks to read, and whether the command is linked.

DATA-IN: The actual data is transferred from the TARGET to the initiator during the data-in phase.

STATUS: The disk controller sends the status of the command that was executed during this phase.

MESSAGE-IN: During this phase, the disk controller sends a message describing the execution of the command it just executed. The linked command information would appear in the message sent during this phase, for example.

BUS DISCONNECT: After a disk controller sends a command complete message, it disconnects from the SCSI bus by releasing the BSY* signal.

The justification for a script is as follows. On the SCSI bus, the TARGET is always the SCSI device that dictates the sequence of bus phases that occurs during a communication with the initiator (this communication is

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Emerson MVME147 manual Notes

Contents

Introduction FeaturesGENERAL INFORMATION Modes of OperationMVME147 SCSI Firmware Entry Points The SCSI firmware initializes these vectors Equipment Supported CONTROLLE DEVICE CONTROLLECONTROLLE PARTDEVICE Devices Supported Under Common Command SetCONTROLLE PARTDOCUMENT TITLE Related DocumentationMOTOROLA PUBLICATION NUMBERManual Terminology MOTOROLAGENERAL INFORMATION Introduction CUSTOM SCSI PACKETSInitiator Role Custom Packet CUSTOM SCSI PACKETS Initiator Role Custom Packet NOTES PHASE CODE PHASEInitiator Role Custom Packet +$00 +$68 status Note ASYNC the firmware status xxxxxxxx xxxxxxxx Page CUSTOM SCSI PACKETS Initiator Role Custom Packet CUSTOM SCSI PACKETS TARGET Enable Custom Packet TARGET Enable Custom PacketNOTES Status from SCSITARGET Enable Custom Packet TARGET Sequence Custom Packet TARGET Sequence Custom Packet CUSTOM SCSI PACKETS NOTESTARGET Sequence Custom Packet WORDS $04 and $06 CUSTOM SCSI PACKETS TARGET Sequence Custom Packet CUSTOM SCSI PACKETS TARGET Sequence Custom Packet RETRY COUNT. Not used by the TARGET role firmwareCUSTOM SCSI PACKETS Control Flags PACKET RETURN STATUSPacket Return Status SCSI The command was retried retry count times Bit 3 FM Filemark Bit 4 COMMAND RETRY1 = Retries were performed Bit 5 COMMAND RE Packet Return Status Bit 2 EOM End of mediaPACKET RETURN STATUS Codes Table 3-1.Packet Status CodesIntermediate Return CODECODE Final Return CodesTable 3-1.Packet Status Codes Intermediate ReturnCODE Table 3-2.Packet Status Codes cont’dSCSI Bus Reset Packet section in Chapter MEANINGController-Dependent Request-Sense-Data Error-Class7 CodesTable 3-3.Packet Status Codes cont’d CODECODE SCSI Status Returned in Status PhaseTable 3-4.Packet Status Codes cont’d MEANINGCODE Request-Sense-Data Error-Class0 through 6 CodesTable 3-5.Packet Status Codes cont’d Controller-DependentPage PACKET RETURN STATUS SCSI FIRMWARE INTERRUPT STRUCTURE SCSI Firmware Interrupt StructureSCSI FIRMWARE INTERRUPT STRUCTURE SCSI_ACTV WRITING A DRIVERSCSI_CMD SCSI_INTInterface Rules for the SCSI Firmware Passing Commands to the SCSI FirmwareBuilding the Packet Figure 5-1.SCSI Disk Driver Interface to VERSAdosInterface Rules for Multiple Callers WRITING A DRIVER Care must be taken not to modify the contents of WRITING A DRIVER Interface Rules for the SCSI Firmware FUNNEL WRITING A DRIVER Interface Rules for the SCSI Firmware WRITING A DRIVER MOVE.W 2A2,D0 THE CODE BELOW HANDLES FINAL RETURN CODES Interface Rules for a Single Caller WRITING A DRIVER Introduction TARGET ROLE ROUTINESMVME147 SCSI Firmware Background SCSI Versus SASI Rules Custom Sequence PacketCommand Table ScriptEnabling TARGET Role Enabling TARGET Role Servicing the TARGET Requests Servicing the TARGET Requests TARGET ROLE ROUTINES Servicing the TARGET Requests TARGET ROLE ROUTINES Servicing the TARGET Requests TARGET ROLE ROUTINES Introduction SCSI PACKETSTable 7-1.SCSI Functions SCSISCSI Functions cont’d Read/Write PacketTable SCSIDISK and TAPE Controller logical unit in SG table, if zero SCSI PACKETS Old Packet Supported for Compatibility+$12 in SG table, if zero |function code 3 bits DMA Scatter/Gather Table EntryRead/Write Packet 1 = link to next entryFor example $5 isCOMMAND COMMANDAttach/Detach Packet all devices CONTROLLERCOMMAND Attach/Detach Packet all devicesSCSI PACKETS +$1E FM encoding, single Controller type refer xxxxxxxx attributes byte offset +$20 Single track density Drive type 0 = 3½, 5¼ Attach/Detach Packet all devicesExample for floppy 3½, 5¼,3½, 5¼ 3½, 5¼3½, 5¼, 3½, 5¼+$04 Minimum read QIC-24 if this is set to 0, the +$00 Reserved Interrupt level +$00 +$9E $00 Format Packet Assign Alternate Sector Packet SCSI COMMAND+$0E Assign Alternate Sector Packet SCSI SCSI PACKETS DEFECT LIST TYPE0 Note 3, NOTES Head Bytes from Index MSW NoteSCSI Bus Reset Packet Controller logical unit SCSI Controller Reset Packet Erase Packet+$12 Rewind Packet Device logical unit Read Block Limits Packet SCSI PACKETS where n = number of blocks or filemarks to Space Status from SCSI The table below shows the write filemarks packet Write Filemarks PacketWrite Filemarks Packet Controller logical unit The controller must be in general or read mode Verify CRC PacketTape Mode Select/Sense Packet Tape Mode Select/Sense Packet Number of tracks on Inquiry Packet +$00 Reserved +$1A Load/Unload Packet +$14 Recover Buffer Data Packet +$0C Request Sense Data Packet Controller logical unit Check Status Packet Open Packet SCSI PACKETSOpen Packet SCSI PACKETS BYTE COMMON COMMAND SET AND DISK OPERATIONBYTE OFFSET BYTE OFFSET BYTEBYTE OFFSET ENTRY NUMBER BYTE OFFSETCOMMON COMMAND SET AND DISK OPERATION NOTESSend mode select command COMMON COMMAND SET AND DISK OPERATION BYTE OFFSET DEFECT LISTDEFECT LIST TYPE NOTESBYTE OFFSET Mode Select HeaderBYTE OFFSET Block Descriptor BYTE OFFSETBYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONNOTES Block Descriptor Mode Select HeaderBYTE OFFSET BYTE OFFSETNOTES BYTE OFFSETBYTE OFFSET VALUEVALUE Mode Select Command CDBBYTE OFFSET COMMENTSBYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONMode Select Header Block DescriptorPage code BYTE OFFSETBYTE OFFSET BYTE OFFSET COMMON COMMAND SET AND DISK OPERATIONNOTES TYPE ATTRIBUTE FLAGSMEDIA Mode Select HeaderMEDIA COMMON COMMAND SET AND DISK OPERATIONATTRIBUTE FLAGS TYPENOTES BYTE OFFSETBYTE OFFSET VALUEPin 2 and Pin 34 Definition for High Density PIN 34 CONTROLCOMMON COMMAND SET AND DISK OPERATION Pin 2 and Pin 34 Definition for Low DensityCOMMENTS PIN 34 CONTROLPIN 2 CONTROL Pin 34 = driveA-22