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Each AHA-1740A/1742A/1744 is equipped with an FCC compliance label which shows only the FCC Identifica- tion number. This device complies with part 15 of the FCC rules. Operation is subject to the following two condi- tions: (1) this device may not cause harmful interference and (2) this device must accept any interference received, including interference that may cause undesired operation.
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Table of Contents Interrupt Initialization... 5-32 Chapter Six - Enhanced Mode Firmware Description Introduction... 6-1 Control Block... 6-3 Command Word... 6-4 Flag Word 1 ... 6-4 Flag Word 2 ... 6-6 Data or Scatter/Gather List Pointer ... 6-10 Data or Scatter/Gather List Length... 6-11 Status Block Pointer ...
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SCSI Bus Reset Handling ... 6-46 Reset Initiated by the Host... 6-46 Reset Initiated by the Host Adapter ... 6-47 Reset Initiated by Another SCSI Device... 6-47 Chapter Seven - Onboard BIOS Interface Introduction ... 7-1 Operation with the Standard Interface ... 7-1 No Standard Hard Disks Installed...
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Problems Detected During Installation... 10-6 Chapter Eleven - Glossary Glossary of Terms ... 11-1 Appendix A - Memory Cycle Timing Diagram AHA-1740A/1742A/1744 Timing Diagram ... A-1 Appendix B - Connector Pinout Internal Connector Pin Assignments ... B-1 External Connector Pin Assignments ... B-3 Appendix C - Register Reference System Register Reference...
Preface This Technical Reference Manual provides technical information for Adaptec’s AHA-1740A/1742A/1744 EISA-to-Fast SCSI Host Adapters. It is prepared for cus- tomer technical personnel requiring detailed information on the operation of the board at a register and command protocol level. Documentation of board schematics, integrated circuits, microcode and BIOS routines is not provided.
Conventions The following typographic conventions are used throughout this Technical Reference Manual. bold Used for keystrokes (.. press the Enter key ..) and screen selection fields (.. select Backup Device and ..). Helvetica Used for operator entry that must be typed exactly as shown ( ..
Disconnect/Reconnect support maximizes bus utilization for multiple target systems. Target mode opera- tion allows the AHA-1740A/1742A/1744 to receive information from other host adapt- ers. Scatter/Gather allows high performance even in systems with fragmented memory buffers.
EISA-SCB compatible (Enhanced Mode) SCSI Features Adaptec has long been a supplier of leading edge SCSI products and the AHA- 1740A/1742A/1744 is no exception. The board uses industry-standard protocol ICs which fully comply with the 1990 ANSI SCSI specification, including: Maximum synchronous SCSI transfer rate of 10.0 MBytes/second (Fast SCSI)
AHA-1742A Fast SCSI-to-EISA Host Adapter with floppy diskette controller AHA-1744 Fast differential SCSI-to-EISA Host Adapter The AHA-1740A/1742A/1744 microcode is available in two separate versions which co- exist simultaneously in the onboard PROM, but must be configured into one of the two available modes:...
Standard Mode allows software drivers written for the AHA-1540 or AHA-1640 fami- lies to run unaltered on the AHA-1740 family. There is no performance penalty for this on the EISA bus. The AHA-1740A/1742A/1744 still performs 32-bit transfers at speeds up to 33 MBytes/second.
EISA-to-Fast SCSI Host Adapter Product Specifications Physical Dimensions Length 13-3/8 inches Width 5/8 inch Height 5 inches Standard EISA-compatible form factor. Power Requirements +5.0 +/- 0.25 Volts at 2.9 Amps maximum. Environmental Requirements Temperature 0-55 C (operating or storage) Reliability Information Mean Time Between Failures: 100,000 hours (calculated per Mil Handbook 217E, ground benign, 40 Mean Time Between Failures: (calculated)
SCSI Interface Electrical Interface for AHA-1740A/1742A As specified by ANSI X3.131-1986 for single-ended operation. Output Signals All signals use open collector or three-state drivers. Each signal driven by a SCSI de- vice has the following output characteristics when measured at the SCSI device’s...
EISA-to-Fast SCSI Host Adapter Electrical Interface for AHA-1744 As specified by ANSI X359.2/86-109 Rev. 10h for differential alternatives. Output Signals Each signal driven has the following output characteristics when measured at the SCSI device’s connector: Signal Definition Low-level output voltage High-level output voltage Differential output voltage and V...
Complete cable assemblies are available from a number of manufacturers. Among them are: Manufacturer Amphenol Interconnect Products Lynn Products Inc. Quitec Interconnect Systems Icontec Enhance Cable Technology 1- 8 AHA-1740A/1742A/1744 Model Part Number Connector 749111-4 Back Shell 749193-1 Connector FCN-237R050-G/F...
Chapter Two Architecture Hardware The hardware of the AHA-1740A/1742A/1744 products is based on the latest VLSI technology for maximum performance in a minimum of board space. Where commer- cial products with sufficient performance and functionality were not available, Adap- tec has developed custom circuits using its long experience in high-performance silicon design for peripheral control applications.
Bus Master DMA The AHA-1740A/1742A/1744 controls the host EISA bus as a master and transfers data directly to and from main system memory. This implementation is known as Bus Master DMA. Bus Master DMA greatly reduces the host software overhead be- cause the host CPU is no longer required to maintain the DMA channel’s address...
Bus Auxiliary Interface Chip (AIC-565) This highly integrated ASIC (Application Specific Integrated Circuit) device devel- oped by Adaptec is also used with the AHA-1540B host adapter family. It provides the Standard Mode programming interface and implements the following main func-...
The microprocessor interface has a 12 mA drive buffer on the data bus plus 100% hardware register compatibility for standard systems. The 16-byte FIFO with programmable thresholds is extremely useful in multimaster systems, or AHA-1740A/1742A/1744...
Disconnection Reconnection Command completion Using the same mailbox protocol, the AHA-1740A/1742A/1744 can operate as a proc- essor-type device serving as a multitasking target to other initiators. This feature al- lows high bandwidth communication between multiple hosts. In addition, the AHA-1740A/1742A/1744 firmware cooperates with the BIOS in- stalled on the host adapter to emulate the standard DOS BIOS calls.
A Command Control Block is also used to service an operation requested by another initiator when the AHA-1740A/1742A/1744 is being addressed as a SCSI Processor device. The CCB is defined completely in Chapter Five, Standard Mode Firmware Description.
EISA-to-Fast SCSI Host Adapter A typical CCB is shown below: Byte 0 Tar/Init 18 + m Command Descriptor Block The Command Descriptor Block (CDB), a part of the Command Control Block, is a standard format command packet that is transmitted to the addressed SCSI device. It contains all the command information required by the SCSI device to perform the desired operation.
Multiple tasks may be started against a target/LUN or against multiple targets/Logi- cal Units. Since only one task can be active against any one LUN at a time, all other tasks for the same LUN are queued. Other LUNs may have active tasks at the same time. AHA-1740A/1742A/1744...
ASW-1440 v3.0 and later (ASPI Manager for Novell NetWare ASW-1450 v1.0 and later (SCSI Manager for SCO UNIX In order to use the Enhanced Mode, the AHA-1740A/1742A/1744 must be correctly re- configured. Use the EISA Configuration Utility (EISA) that came with your EISA sys- tem and the EISA configuration files on the ASW-C174 diskette provided with the AHA-1740A/1742A/1744.
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Command Word Flag Word 1 Flag Word 2 Status Block Pointer Chain Address Sense Information Pointer Sense Length Data Checksum CDB Byte 0 CDB Byte 2 CDB Byte 4 CDB Byte 6 CDB Byte 8 CDB Byte 10 AHA-1740A/1742A/1744 Byte Offset...
At least one set of terminators must remain installed or the LED will stay on, indicating that the AHA-1740A/1742A/1744 is receiving an active RST signal. The flash code and associ- ated failure modes are indicated in the following table.
Adaptec bulletin board for a download copy of the files. The Adaptec bulletin board number is (408) 945-7727. Use 8 data bits, 1 stop bit, no parity, 1200, 2400, or 9600 baud.
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SCSI bus and the specific structure within the freeform data area and is not specified by the EISA specification. Adaptec uses a data structure for each device (SCSI ID #n) consisting of two bytes, shown in the following table:...
Unlike AT/ISA boards, but like Micro Channel boards, EISA boards do not normally require hardware jumpers. Ensure that you have the correct version of the AHA-1740A/1742A/1744 for your sys- tem. The AHA-1740A/1742A support the more common single-ended SCSI interface. The AHA-1744 supports the differential interface, more common on SCSI peripherals on minicomputers.
SCSI hard disk. The AHA-1740A/1742A/1744 BIOS fully supports the extended partitioning ca- pabilities of DOS for up to two drives. Adaptec supplies a range of products based on the Advanced SCSI Programming Interface (ASPI) architecture that allow the sup- port of more than two physical or logical devices under DOS.
The details vary from vendor to vendor. Refer to the system documentation for details. The Adaptec AHA-1740A/1742A/1744 32-bit EISA bus-to-SCSI bus host adapter has been designed to operate as shipped in the majority of EISA class computers. A board direct from the factory is normally shipped with the ASW-C174 Configuration Utility.
SCSI devices generate parity, it is recommended that parity checking be turned on for all devices. Please note that generating parity and checking parity are two separate functions. The AHA-1740A/1742A/1744 configuration overlay can be used to enable/disable parity checking for each SCSI ID.
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SCSI cable should have terminators installed. On the AHA-1740 and AHA-1744, these are RN2, RN3, and RN4, located to the side of the internal SCSI connector. On the AHA-1740A and AHA-1742A, these are RN5, RN6, and RN7, located below the internal SCSI connector.
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7. Align the EISA bus connector on the bottom of the AHA-1740A/1742A/1744 to the open chassis slot with the slot cover removed. Ensure the external connector and bracket pass cleanly through the cutout in the rear wall. 8. Firmly plug the board into the slot. Use the screw from the corresponding expan- sion slot cover to secure the board bracket to the system frame.
System Configuration When it is being installed in an EISA system, the AHA-1740A/1742A/1744 requires an EISA system configuration file. This may be part of the system software or may be supplied on a separate diskette. If it is separate, installation is easier if the contents of the separate diskette are copied onto the main bootable system configuration disk.
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1740A/1742A/1744, copy the contents of the ASW-C174 diskette with the AHA- 1740A/1742A/1744 configuration files to the boot floppy and run the configuration program. !adp0000.cfg for the AHA-1740 !adp0001.cfg for the AHA-1740A !adp0002.cfg for the AHA-1742A !adp0400.cfg for the AHA-1744 In addition, run adp0000.ovl for all boards. The configuration utility will usually allow selection among a number of options, including copying new con- figuration files.
EISA-to-Fast SCSI Host Adapter MCS Configuration For configuration under MCS, select the slot in which the AHA-1740A/1742A/1744 is installed and press Enter. The screen will display the System Configuration De- tailed View. These settings should normally not be changed for Standard Mode opera- tion.
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When Enhanced Mode is selected, IRQ 11 is used by default. By default, if multiple AHA-1740 family host adapters are in the system in Enhanced Mode, all will use IRQ 11. For the MCS EISA Configuration Utility, this can be shown by selecting Change System Resources under the Edit pull down menu (or entering Ctrl- R) when the Host Adapter Interface Mode is highlighted.
EISA-to-Fast SCSI Host Adapter Standard Mode SCSI Configuration The view for Standard Mode is a simple selection for those variables which apply to all SCSI peripherals connected. This is shown in Figure 3-5. Normally, the default of one device at SCSI ID 0 with normal default parameters is selected. System Global Host Adapter SCSI Configuration Options Enable Parity Checking...
When this option is selected, use the cursor keys to move among the options shown in Figure 3-7. 3-12 System Configuration Detailed View Edit View Settings Configuration Settings for SCSI Devices 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 (MBs per second) Slot 4 AHA-1740A/1742A/1744 F1=Help Help...
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Maximum Synch Transfer Rate allows selection of the highest data transfer speed that the host adapter will attempt with that peripheral. The AHA-1740A/1742A/1744 support rates up to the Fast SCSI maximum of 10 MBytes/second. System Configuration Detailed View...
Int 11. When multiple 1740A/1742A/1744s are not attached to the same SCSI bus, then sharing of interrupts in Enhanced Mode is acceptable. 3-14 System Configuration Detailed View Edit View Settings Configuration Settings for SCSI Devices (MBs per second) Slot 4 AHA-1740A/1742A/1744 F1=Help Help...
J6 on the lower left of the board. If the jumper is removed, the board will return the identity of an AHA-1740A to any software inquiry command. This allows software to use the appropriate configuration file for the main part of the board, as described previously.
At the DOS prompt, enter adl to bring up Adaptec’s AHA-1740/1744 download utility. The following will describe the procedures and the screen display. During the opera- tion, F1 can be pressed to display help messages and Esc to exit the current message box and the utility.
Following is a description of each operation. Download Firmware (AHA-1740/1744 Only) The AHA-1740/1744 (not the AHA-1740A or AHA-1742A) have the unique flexibility of allowing firmware to be altered or upgraded while the board is installed in a sys- tem. This is done by using a utility on the ASW-C174 and either the firmware files supplied or new files supplied with ASW-M174.
After reading the host adapter information, press Esc to continue. Have this information available when contacting Adaptec with questions about firm- ware or upgrades. If multiple host adapters are installed, the Esc key can be used to select another host adapter from the List of Host Adapters menu.
For odd-byte starting addresses, the first transfer will be an 8-bit transfer, For odd-word starting address, the first transfer will be a 16-bit transfer. The SCSI port is controlled by the AIC-6251, and Adaptec SCSI protocol device for fast (10.0 MBytes/second transfers) which supports arbitration, selection, and reselec- tion with a minimum of processor intervention.
WRITE: Reserved, do not write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 AHA-1740A/1742A/1744 READ: Status Register Bit 7 Self Test in Progress (STST) Bit 6 Internal Diagnostic Failure (DIAGF) Bit 5 Mailbox Initialization Required (INIT)
(Host Adapter Status Port bit 4) are set when the reset processing is completed. This indicates that the AHA-1740A/1742A/1744 mailbox structure must be reinitial- ized and that no other operations are active on the host adapter. See the section on Reset Functions for a description of the overall reset structure.
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The host adapter must be reset by setting the Hard Reset bit (bit 7 of the Control Port) to clear the error. If the AHA-1740A/1742A/1744 again detects an error, troubleshooting procedures must be performed to identify and correct the er- ror condition.
EISA-to-Fast SCSI Host Adapter Hardware Functional Description Bit 2 - Data In Port Full (DF) The host uses the DF bit to synchronize transfers of data from the host adapter to the host. When the DF bit is set to one, the host adapter has placed a byte in the Data In Port for the host to remove and process.
This bit, when one, indicates that the interrupt to the host has been established. The interrupting condition is identified in bits 0 to 3. Bit 6 - Reserved Returned as zero. Bit 5 - Reserved Returned as zero. Bit 4 - Reserved Returned as zero. AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Hardware Functional Description Bit 3 - SCSI Reset Detected (SCRD) This bit, when one, indicates that a SCSI Reset has been received on the SCSI bus. The Any Interrupt bit and the AT interrupt signal will also be set. The host adapter supports SCSI Soft Reset (see Section 4.3).
In addition to the RESET signal, the setting of the HRST bit (bit 7 of the Host Adapter Control Port) will force a hardware reset to the AHA-1740A/1742A/1744. Regardless of the source, a Hard Re- set forces the following actions on the AHA-1740A/1742A/1744.
RESET signal or by the setting of the HRST bit. This reset is described in the Hard Reset Operations section. The SCSI Reset condition may be invoked by the AHA-1740A/1742A/1744 as part of the recovery mechanism for a bus phase error. Bus phase errors may include detec- tion of an invalid information transfer phase or detection of an impossible phase se- quence (Command Phase after a Data Phase in the same command).
For certain types of systems that frequently do back-up or check point their transactions, that reinitialize quickly and easily, or that infrequently do resets, the Hard Reset option is appropriate. The AHA-1740A/1742A/1744 responds to a SCSI Reset condition by executing only the Soft Reset option, but it notifies the host when- ever a SCSI Reset condition has been established by causing an interrupt to the host.
The expansion board identifier registers are always available for access on the bus by the host system. They are used to transfer basic information on the identity of the board and its revision level from the AHA-1740A/1742A/1744 to the host. Host ID 0 (HID0, zC80, R) HID0 is the first byte of the expansion board ID.
Three, ADL Utility. It is written by the local processor and read by the system processor. RESDRV, HARDST or SOFTRST has no effect. The revision code for the AHA-1740/1744 is 00h, the AHA-1740A is 01h and the AHA-1742A is 02h. Board Configuration Registers These registers are used by the host process to define parameters on the board neces- sary for normal operation.
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EISA-to-Fast SCSI Host Adapter I/O Port Address (PORTADDR, zCC0, W/R) PORTADDR selects the base address for the I/O port interface. It is compared with the system address every cycle. If a match occurs, data will either be driven or sam- pled on the bus.
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1 0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 1100-1111 4-14 BIOS Address Table BIOS Address (hex) Not used Not used C8000 CC000 D0000 D4000 D8000 DC000 E0000 E4000 E8000 EC000 Not used AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Interrupt Definition (INTDEF, zCC2, W/R) An interrupt channel may be selected from one of several on the EISA bus. The inter- rupt may be programmed as high true or low true. When high true, the interrupt is a two state signal and acts like an edge triggered interrupt, and may not be shared with another board.
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0 1 1 0 0 1 1 1 1000-1111 Bus Definition (BUSDEF, zCC4, W/R) This register allows the configuration of certain EISA bus features supported by the AHA-1740A/1742A/1744. Definition Reserved DMA Channel for Standard Mode Bit 3 BUSON These bits are written in order to set the time that the AHA-1740 stays on the bus when preempted by another device.
EISA-to-Fast SCSI Host Adapter Reserved Registers The following registers are reserved for future use. Reserved 0 (RESV0, zCC5, W/R) Reserved 1 (RESV1, zCC6, W/R) Reserved 2 (RESV2, zCC7, W/R) I/O Port Register Standard Mode (Group 1) The I/O Control Standard Mode (Group 1) registers form the primary communication channel between the system and the adapter for Standard Mode operation.
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CMD/DAT (Base + 1) with a command or parameter. This bit is polled by the local processor to determine if a byte is ready. It is cleared when the local processor reads the LCMDDAT register. (0) 4-18 AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Definition HAVAIL Information is Available to the system. When this bit is one, the local pro- cessor has loaded CMD/DAT (Base + 1) with data. It is cleared when the system reads CMD/DAT. This bit is also read by the local processor. (0) Reserved.
This process repeats until the transfer is complete. In response to a reset, if the host adapter passes diagnostics, then a value of 00H will be loaded in MBOXIN0. ATTN will also be read to clear the Busy bit. If the host 4-20 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter adapter fails diagnostics, then the local processor will load the value appropriate for the failure in MBOXIN0, according to the following list, and read ATTN to clear the busy bit. Reset Codes No Error Microprocessor ROM Test failure RAM test failure Power Protection device error Microprocessor internal peripheral test failure...
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5 = CCB completed with success after retry 7 = Adapter hardware failure A = Immediate command completed with success C = CCB completed with error D = Asynchronous event notification E = Immediate command completed with error Target ID SCSI ID of command 4-22 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter Enhanced Mode (Group 2) Status (G2STAT, zCD7, R) Definition Reserved Mailbox out empty Set to one by firmware when it is done with the mailbox out. Cleared by software writing to any mailbox out location. Interrupt pending Reflects the state of the EISA interrupt line from the Enhanced Mode (Group 2) interrupt before the enable/disable logic.
Because of this multibyte interchange of information between the diskette controller and the proces- sor, each command can be considered to consist of three phases: 4-24 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter Command Phase: The processor issues a sequence of write commands to the diskette controller that direct the controller to perform a specific operation. Execution Phase: The diskette controller performs the specified operation. Result Phase: After completion of the operation, status and other housekeep- ing information is made available to the processor through a sequence of read operations from the data register.
Firmware Download (AHA-1740/1744 Only) The AHA-1740A/1742A permanently stores both Standard and Enhanced Mode firm- ware in an EPROM. A microcode upgrade consists of replacing that EPROM with an- other, and is seldom required. Please contact Adaptec for further information.
EISA-to-Fast SCSI Host Adapter Hardware Configuration Requirements The following host adapter configuration options must be defined prior to setting the card enable bit in register zC84: The BIOS location must be set to an address which does not conflict with other system resources.
Enhanced Mode Firmware Description. FlagWord 1 Options Disable Status Block (bit 14) is supported. Setting this bit will disable the writing of the termination status block if no error occurs. All other bits should be set to zero. 4-28 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter Refer to Appendix D, EISA Free-Form Data for the initial SCSI subsystem data structure. Configuration Byte Description and Defaults The following describes the SCSI device configuration byte format. Firmware default values are also given. These defaults are used by the firmware to interface with the various targets in the event that no Initialize SCSI Subsystem command has been re- ceived by the host adapter.
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EISA INT 15h call. The name of the function type for this data is stored by the configuration utility at offset 23h. This type string must be the eight- character ASCII string SCSIDEVS. Additional information on the function configura- tion information data block is given in the EISA specification. 4-30 AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Function Configuration Information Data Block for SCSI Subsystem Data Byte Offset Description Function Information Byte B6 = 1 to indicate free from data Type and Subtype ASCII string "SCSIDEVS" Length of the following data block ASCII string "AHA-174x" 7C-7Fh Reserved SCSI device 0 byte 0...
Standard Mode Firmware Description Host Adapter Command Overview Standard Mode is the mode in which the AHA-1740A/1742A/1744 can operate in or- der to run existing software for earlier Bus Master host adapters. In Standard Mode, the AHA-1740A/1742A/1744 supports two types of commands: SCSI and adapter com- mands.
Mailbox Out entries and the same number of Mailbox In entries will be assigned beginning at the Mailbox ad- dress. The total number of bytes reserved for the mailbox area will be eight times the AHA-1740A/1742A/1744...
Start PC AT BIOS Command (Operation Code 03) This command is used by the Adaptec BIOS to communicate with the host adapter firmware. The command is not available for use by programs other than the Adaptec BIOS.
This value indicates an ASCII value from 0-9, that indicates the first digit of the firmware base code revision installed in the AHA-1740A/1742A/1744. Firmware Revision Level (Second byte) This value indicates an ASCII value from 0-9, that indicates the second digit of the firmware base code revision installed in the AHA-1740A/1742A/1744.
Set Bus On Time (Operation Code 07) This command is not used by the AHA-1740A/1742A/1744 but is supported in order to be compatible with software written for earlier host adapters, such as the AHA- 1542B.
Set Bus Off Time (Operation Code 08) This command is not used by the AHA-1740A/1742A/1744 but is supported in order to be compatible with software written for earlier host adapters, such as the AHA- 1542B. This command sets the time that the host adapter will spend off the bus during a data transfer.
AT Bus Transfer Speed 80-FFh Due to the internal differences between the AHA-1740A/1742A/1744 and earlier host adapters, the data is not actually used but is saved and returned in the Return Setup Data command. The command is accepted only for compatibility.
The DMA arbitration priority, the Interrupt channel, and the SCSI ID of the adapter are returned by this command. The three bytes of information are returned in the fol- lowing format: Byte Description DMA Arbitration Priority AHA-1740A/1742A/1744 Bit 7 LU 7 Installed Bit 6 LU 6 Installed Bit 5...
LU will be treated as installed. If the bit is zero, the LU will be treated as not installed. If the AHA-1740A/1742A/1744 does not have the Target Mode feature installed, the host adapter will indicate an invalid host adapter command. If an attempt is made to...
SCSI selection time out. Most reset operations, including Soft Reset, Hard Reset, and Power-On Reset will return the AHA-1740A/1742A/1744 Target Mode to the dis- abled state. SCSI resets, generated either by the host or by other SCSI devices, will not change the previously established enabled or disabled state of Target Mode.
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EISA-to-Fast SCSI Host Adapter Byte Description Bus Off Time Number of Mailboxes Mailbox Address (MSB) Mailbox Address Mailbox Address (LSB) 08-0F Synchronous Transfer Agreements Returns information about the synchronous negotiation with Target 0. The byte will be 00H for the address of the host adapter.
Byte 1 Buffer area address Byte 2 Buffer area address, Least significant byte 5-12 AHA-1740A/1742A/1744 Meaning Each bit corresponds to a SCSI device, e.g., bit 0 corresponds to the device at SCSI address 0. When set to one, the host adapter will prevent the SCSI device from disconnecting.
EISA-to-Fast SCSI Host Adapter Read Adapter Channel 2 Buffer (Operation Code 1B) After receiving this command, the host adapter expects three outbound information bytes to be transferred which point to an area of 64 bytes in system RAM. The area pointed to will be used as a buffer to receive 64 bytes of information transferred from the host adapter’s channel 2 buffer to the host’s memory using the host adapter’s DMA circuitry.
Returned echo value Adapter Diagnostic (Operation Code 20) Unlike other Adaptec host adapters, this command does not cause the host adapter to perform its internal self-diagnostic. A host adapter Hard Reset is not executed, nor is a SCSI bus reset. The host adapter need not be reinitialized after this command be- fore resuming normal operation.
Initialization command was set to four. The base address is the address specified by the Mailbox Address field. The Adaptec BIOS initializes the AT DMA controller to accommodate Bus Master DMA. If the host adapter BIOS is removed or disabled, the host DMA controller must be initialized, via software, for Bus Master DMA operation.
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In Target Mode, one CCB may be presented for each unique combination of LUN, In- itiator, and direction. If a second CCB to the same LUN and initiator with the same direction bit is sent to the AHA-1740A/1742A/1744, the CCB will be returned with a host status of 19h, Duplicate CCB Received.
EISA-to-Fast SCSI Host Adapter host adapter will not change the MBOA interrupt bit and will continue to scan for other stored MBO entries. 3. If interrupts other than the Mailbox Out Available interrupt are pending, the host adapter will wait for the pending interrupts to be cleared before setting the Mail- box Out Available Interrupt.
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Byte Definition MBI Status This byte specifies the state of the MBI entry. Initiator and LUN 5-18 AHA-1740A/1742A/1744 Value Meaning Mailbox In is free CCB completed without error. CCB pointer indicates location of successfully completed CCB. CCB aborted by host. CCB pointer indicates location of CCB that was aborted.
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EISA-to-Fast SCSI Host Adapter Byte Definition Data Length The CCB Required Mailbox In entries are only generated when a command has been received by the host adapter in Target Mode. For the CCB Required Mailbox In en- tries, byte 0 takes on a distinctive value of 10h, indicating the MBI entry is filled and the MBI entry is being presented to request a CCB appropriate to service a SCSI transaction for which no CCB was available.
Operation Code Address and Direction Control SCSI Command Length Request Sense Allocation Length/Disable Auto Sense Data Length (Byte 4 most significant) 5-20 AHA-1740A/1742A/1744 Note Value Meaning SCSI Initiator command Target Mode command SCSI Initiator command with Scatter/Gather SCSI Initiator command,...
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EISA-to-Fast SCSI Host Adapter Byte Description Data Pointer (Byte 7 most significant) 10-12 Link Pointer (Byte 10 most significant) Command Linking Identifier Host Adapter Status (HASTAT) Target Device Status (TARSTAT) 16-17 Reserved (00) 18-n SCSI Command Descriptor Block (Length specified by byte 2) Reserved for Request Sense information bytes (Length of reserved space in...
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18+m The bytes of the CCB are defined further below: Byte 0: Command Control Block Operation Codes The AHA-1740A/1742A/1744 supports six CCB operation codes. The valid command values are shown below: SCSI Initiator Command Control Block SCSI Target Command Control Block...
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EISA-to-Fast SCSI Host Adapter Standard Mode Firmware Description AHA-1740A/1742A/1744. Operation codes 00h and 03h differ only in the updating of Bytes 4, 5, and 6, following completion of the command. If the operation code value is 01h, the CCB is intended to service a Send or Receive command sent to the host adapter as a target from another initiator.
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The SCSI specification indicates that a Request Sense command must be exe- cuted before any other command is executed in order for the host initiator to be sure of obtaining the error information. Since the AHA-1740A/1742A/1744 host adapter has the capability of queuing commands for execution, the host adapter itself must take charge of generating the Request Sense command.
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Command Descriptor Block generated by the host adapter. If an operation that treats the AHA-1740A/1742A/1744 as a Target Mode device fails and presents a check condition status byte, the Initiator should return a Request Sense command.
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More than one CCB was received to service data transfer between the same target LUN and initiator SCSI ID in the same direction. Invalid CCB or Segment List Parameter A segment list with a zero length segment or invalid segment list boundaries was received. A CCB parameter was invalid. 5-26 AHA-1740A/1742A/1744...
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CCBs, the CDB provided from the initiator is returned to the host in this space. Byte 18+n - 18+n+m : Allocated for Sense Data If a check status condition is detected by the AHA-1740A/1742A/1744 as it completes an operation on the SCSI bus, the host adapter automatically executes a Request Sense command with the data length specified by request sense allocation length.
The direction of transfer with respect to the data area and the checking of the length of the data transfer to the data area are both managed by the AHA-1740A/1742A/1744 according to the requirements of the particular mode and control bit set-up.
Disconnection and reconnection on the bus are automatically taken care of by the AHA-1740A/1742A/1744. As the host adapter starts the SCSI operation, it will first determine if the addressed target/LUN is busy. If the target/LUN is busy, the command will be placed in the task queue to be tried again later.
CCB was already finished nor- mally and returned. The AHA-1740A/1742A/1744 scans the MBOs in a round-robin fashion. This is to en- sure that all of the mailboxes will be scanned with equal probability. A host can mini- mize the AHA-1740A/1742A/1744 MBO scan time by using MBOs sequentially.
The DMA circuitry must be set to a special state to allow the Bus Master operation of the AHA-1740A/1742A/1744 to operate correctly. This state is normally established by the BIOS during initialization so that no other activity is required. If a DMA chan-...
The mask register is a read/write register, and only the bit of inter- est should be cleared. The port address is A1h, and bit definitions follow: 5-32 AHA-1740A/1742A/1744 DMA Controller Port Software Interrupt Vector Location (hex) Int 71...
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EISA-to-Fast SCSI Host Adapter Interrupt Mask Bit Definition (Port Address A1h) Standard Mode Firmware Description Interrupt Int 8 Int 9 Int 10 Int 11 Int 12 Int 13 Int 14 Int 15 5-33...
Block (ECB) in memory. The host then stores the pointer to the ECB in the Mailbox Out, provided that bit 2 of the SCD7 Status register (MBO empty) is true. Due to the speed with which the AHA-1740A/1742A/1744 services the mailbox, the MBO will al- most always be empty.
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Clear EISA Interrupt bit in the control register zCD5. Multitasking is achieved by setting up multiple commands through the mailbox be- fore the first has been completed. The microcode maintains control of up to 64 com- mands executing simultaneously in the host adapter. AHA-1740A/1742A/1744 SCSI ID SCSI ID...
EISA-to-Fast SCSI Host Adapter Control Block The control block is a 48-byte structure created and maintained in shared memory by software in the system unit. It is used to convey requests to the host adapter. Data or Scatter/Gather List Pointer Data or Scatter/Gather List Length CDB Length CDB Byte 1...
Flag Word 1 Flag word 1 is a 16-bit structured field used to specify execution parameters for this control block. Fields that are empty are reserved and should be set to zero. AHA-1740A/1742A/1744 Operations Code...
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EISA-to-Fast SCSI Host Adapter Flag Name and Function Chain No Error The Chain No Error flag (bit 0) indicates whether control block chaining is enabled. If this bit is set to one, chaining is enabled. Upon successful completion of the control block, the host adapter will fetch the next control pointed to by the chain address.
Target SCSI commands. For all other commands, setting this flag to one will result in a specification check. Flag Word 2 Flag word 2 is a 16-bit structured field used to specify execution parameters for this control block. Fields that are empty are reserved and should be set to zero. AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Flag Name and Function Logical Unit Number This field (bits 2-0) specifies the logical unit number of the target for which the com- mand is to be executed. Tagged Queuing This flag (bit 3) indicates whether tagged queuing should be implemented for this control block.
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(Write operation). If a Data In phase is detected, the host adapter will abort the command and report an invalid phase error. The invalid phase error will not be reported if no data phase is detected. AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Flag Name and Function Suppress Transfer to Host Memory This flag (bit 10) indicates whether an incoming data transfer is to be suppressed. This flag will be ignored if the Data Transfer flag (bit 8) is set to zero. If this bit is set to one, the host adapter will accept data from the target, but will not transfer it to host memory.
SCSI command. The number of 8-byte segments is limited to 128 (one pointer and one length), but the host adapter will only store a maximum of 17 segments in its internal memory at a time. The diagram below describes the struc- ture of the Scatter/Gather list. 6-10 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter 1F 1E 1D 1C 1B 1A 19 18 17 16 15 14 13 12 11 10 The data lengths must be less than 4 MBytes and the total length of the transfer must be less than 16 MBytes. Data or Scatter/Gather List Length This 32-bit field contains the length in bytes (least significant byte first) of the data transfer.
The host adapter will then verify the result with the value specified in this field. If the two values do not compare, an error will be reported. This option is currently available only for the Download Firmware command. 6-12 AHA-1740A/1742A/1744 Note...
EISA-to-Fast SCSI Host Adapter SCSI Command Descriptor Block This 6-, 10-, or 12-byte field contains the actual CDB to be sent to the target during command phase. Status Block The status block is a 32-byte structure created in shared memory by software in the system unit.
If this bit is set to one, the host adapter has rejected the control block because its internal storage area is full. No action is taken on the control block. The host should reissue the control block after an outstanding control block completes or after an appropriate time delay. 6-14 AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter Flag Name and Function Specification Check The Specification Check flag (bit 4) indicates that the host adapter detected an error in the control block. If this bit is set to one, the host adapter has rejected the control block due to an error in one of the control block’s fields (i.e., unsupported operation code).
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Resume command for the associated target. It is also cleared by resetting the host adapter or by issuing a Bus Device Reset to the associated target. This flag is set to one for every control block completed while the extended contingent allegiance condition exists. 6-16 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter Host Adapter Status This 8-bit field contains additional error information pertaining to the host adapter or SCSI subsystem in general. This field is valid when the Command Done flag is set to zero and one of the following flags is set to one: Specification Check, Initialization Required, or Major Error/Exception.
This field is valid only if the Data Underrun or Data Overrun flag (Status Word, bits 1 and 5, respectively) is set to one. 6-18 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter If Scatter/Gather was enabled for the associated control block, then this field con- tains the address of the data pointer in the Scatter/Gather list that was most recently used to transfer data. If Scatter/Gather was not enabled for the associated control block, then this field con- tains the address specified in the data pointer field of the control block.
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(if enabled) will interrupt the host by writ- ing to the Enhanced Mode (Group 2) Interrupt Status register. The Mailbox In regis- ters will contain the address of the completed control block. Following are the control block commands described in alphabetical order. 6-20 AHA-1740A/1742A/1744 SCSI ID...
EISA-to-Fast SCSI Host Adapter Download Firmware Options Fields that are empty are reserved and should be set to zero. This command causes the host adapter to overwrite its program memory with data supplied by the host. The host adapter will, if enabled, perform a checksum on the data after it is written to its internal RAM, and compare the checksum to the value stored in the control block.
Flag Word 1 - Disable Interrupt (bit 7) and Disable Status Block (bit 14) are sup- ported. All other flags should be zero. Flag Word 2 - The Calculate Checksum option (bit 11) should be used. All other flags should be zero. 6-22 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter Initialize SCSI Subsystem Pointer to Initialization Configuration Data Length of Initialization Configuration Data Fields that are empty are reserved and should be set to zero. This command allows the host to place a copy of the configuration information per- taining to the SCSI subsystem (stored in system CMOS RAM) into the host adapter’s internal RAM.
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EISA-to-Fast SCSI Host Adapter All bits not defined above are ignored by the host adapter and may be set to either 0 or 1. The Disconnection Enable bit (least significant byte, bit 2) determines whether the host adapter will allow the specified target to disconnect during a SCSI operation. If the enable bit is one, then disconnection is allowed for that device.
(Flag Word 2, bit 11). 6-26 Flag Word 1 Flag Word 2 Status Block Pointer Chain Address Sense Information Pointer Sense Length CDB Byte 0 CDB Byte 2 CDB Byte 4 CDB Byte 6 CDB Byte 8 CDB Byte 10 AHA-1740A/1742A/1744 Byte Offset...
EISA-to-Fast SCSI Host Adapter No Operation Options Fields that are empty are reserved and should be set to zero. If the SCSI ID specified in the Attention register specifies the SCSI address of the host adapter, then this command is intended for diagnostic purposes to test whether the transfer of control blocks and their associated interrupts are working properly.
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Flag Word 1 - Chain No Error (bit 0), Disable Interrupt (bit 7) and Disable Status Block (bit 14) are supported. All other flags should be zero. Flag Word 2 - Logical Unit Number (bits 2-0) are supported. All other flags should be zero. 6-28 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter Read Host Adapter Inquiry Data Options Destination Pointer of inquiry data Fields that are empty are reserved and should be set to zero. This command can be used to obtain release information and revision level of the host adapter’s firmware.
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Disable Status Block (bit 14) are supported. All other flags should be zero. Flag Word 2 - None of the options in Flag Word 2 are supported by this command. The information is written into host memory in the following format. 6-30 AHA-1740A/1742A/1744...
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EISA-to-Fast SCSI Host Adapter No. of LUNs Flags Reserved for Information on SSCI Peripherals Enhanced Mode Firmware Description SCSI Device Type SCSI Support Level Additional Lng No. of CBs Vendor Verification Product Identification Firmware Type Firmware Revision Level Release Date Release Time Firmware Checksum Reserved...
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The actual LUNs supported start at LUN 0 (e.g., if this byte contains a 3, then LUN 0, 1 and 2 are enabled.) Byte 6 indicates the number of control blocks the host adapter can store internally be- fore responding with a queue full status. The flags byte contains the following information. 6-32 AHA-1740A/1742A/1744...
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(e.g., Adaptec). The product identification field contains eight bytes of ASCII data identifying the product name of the host adapter (e.g., AHA-1740A/1742A). The firmware type field contains eight bytes of ASCII data indicating whether the firmware is a standard product or a special version (e.g., Enhanced).
After completion of this command, the host adapter and the target will release contingent allegiance and resume operation for any queued commands. If extended 6-34 Flag Word 1 Flag Word 2 Status Block Pointer Sense Information Pointer Sense Length AHA-1740A/1742A/1744 Byte Offset...
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EISA-to-Fast SCSI Host Adapter contingent allegiance was reported in the status block of the Initiator SCSI com- mand, this command must be followed by a Resume command to release extended contingent allegiance. Supported Options Flag Word 1 - Suppress Error on Underrun (bit 10) and Disable Status Block (bit 14) are supported.
Any value of these bits not defined below may result in a specification check. 6-36 Flag Word 1 Write FIFO Data Pointer Read FIFO Data Pointer Test FIFO Data Length Status Block Pointer AHA-1740A/1742A/1744 Byte Offset...
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EISA-to-Fast SCSI Host Adapter Value Meaning Self-Test The host adapter performs a subset to its self-diagnostic routines that it normally performs at power-up. The two data pointer fields and the data length field is ignored. Test FIFO The host adapter will transfer data from the address in the write FIFO data pointer field (least significant byte first) to its internal FIFO.
SCSI device. The SCSI address of the initiator is supplied in bits 3-0 of the attention register. The logical unit number of the host adapter is supplied in bits 2-0 of Flag Word 2. 6-38 Flag Word 1 Flag Word 2 Status Block Pointer Sense Information Pointer Sense Length AHA-1740A/1742A/1744 Byte Offset...
EISA-to-Fast SCSI Host Adapter Supported Options Flag Word 1 - Scatter/Gather (bit 12) is supported. Suppress Error on Underrun (bit 10) should be used with care since the exact length of the transfer may not be known. Disable Status Block (bit 14) should also be used with care since the status block will return information regarding the actual command received.
The abort operation will have no affect. There is no interrupt associated with the abort operation. Its sole purpose is to pre- maturely terminate any control block queued or in progress. 6-40 AHA-1740A/1742A/1744 Note Note...
EISA-to-Fast SCSI Host Adapter Asynchronous Event Notification An asynchronous event occurs when the host adapter detects an unexpected condi- tion on the SCSI subsystem. Asynchronous Event Conditions A SCSI bus reset has occurred The host adapter was selected by another initiator The host adapter notifies the host of an asynchronous event via an interrupt.
Instead of a control block address, a 32-bit immediate command is stored into the Mailbox Out registers, least significant byte first. The Attention register is then stored with the following value: 6-42 CDB Byte 2 CDB Byte 3 AHA-1740A/1742A/1744 CDB Byte 4...
EISA-to-Fast SCSI Host Adapter The SCSI ID specifies either the SCSI address of a particular target, or the SCSI ad- dress of the host adapter. The host adapter’s ID can be found in bits 3-0 of the SCSI Definition register. When the Attention register is written to, the host adapter is interrupted.
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Asynchronous Event Notification interrupt. Any commands that were outstanding when the SCSI Bus Reset occurred and any commands re- ceived between the reset and the host acknowledgment of the Asynchronous Event Notification interrupt will be returned with error status. The status 6-44 AHA-1740A/1742A/1744...
EISA-to-Fast SCSI Host Adapter returned will reflect that the command was aborted by the host adapter (error code = 05). Any commands received after the acknowledgment of the Asynchro- nous Event Notification interrupt will be operated on normally. Reset Host Adapter If the Attention register contains the SCSI ID of the host adapter, then this com- mand is intended to reset the SCSI subsystem to a known state.
Adapter Reset Option flag is set to zero, the SCSI bus will be reset by the host adapter as part of its reinitialization. There will be no notification of the SCSI reset since it is implied by the Soft Reset. 6-46 AHA-1740A/1742A/1744 Byte Offset...
EISA-to-Fast SCSI Host Adapter Reset Initiated by the Host Adapter The host adapter will reset the bus if it encounters an error on a SCSI operation that it cannot recover from. Some examples include: the target goes to an invalid bus phase, the host adapter cannot force the target to go bus free when attempting to abort a command, or the host adapter cannot send a bus device reset message.
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Asynchronous Event Notification interrupt will be returned with error status. The status returned will reflect that the command was aborted by the host adapt- er (error code: 05). Any commands received after the acknowledgment of the asyn- chronous event notification will be will be operated on normally. 6-48 AHA-1740A/1742A/1744...
SCSI devices other than CCS disk drives, or if support for more than two disk drives is required under DOS, the Adaptec DOS Driver, ASW-1410 must be used. The BIOS provides a very simple single-threaded capability that does not make use of the Mail- box Interface used by more sophisticated programs.
No Standard Hard Disks Installed In this case, two SCSI drives can be supported by the AHA-1740A/1742A/1744 BIOS. SCSI target 0 Logical Unit Number (LUN) 0 is designated as drive 0 (drive C). Either SCSI target 0 LUN 1 or SCSI target 1 LUN 0 may be designated as drive 1 (drive D).
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EISA-to-Fast SCSI Host Adapter BIOS base address in the boards setup registers. In the case where the board is not functioning properly, the BIOS will display the message: Unable to initialize SCSI host adapter! and the BIOS will fail initialization. The failure will be flagged to the system via the BP register so that the system BIOS can halt system initialization until the user strikes a key (F1 on most systems).
The AHA-1740A/1742A BIOS will revector Interrupt 13h so that all calls for disk I/O can be filtered by the AHA-1740A/1742A BIOS. Requests for non-SCSI drives are passed on to the original Int 13h vector which is stored in shadow RAM.
EISA-to-Fast SCSI Host Adapter AHA-1740A/1742A CMOS configuration so the desired boot drive is the first drive found by the system. Interrupt 13h Interface Functionality Disk I/O requests are passed from the operating system to the BIOS through soft- ware interrupt 13h. CPU registers are used to pass a function code as well as the as- sociated parameters for the function.
(it may not be contiguous). The AHA-1740A/1742A BIOS will fully support the VDS specification so that 386 memory management programs will be able to run without a driver as long as they are VDS compliant.
2Ah - Unit Attention, Mode Select Change Undefined error occurred: A SCSI ASC other than those listed was returned by the target. Write Fault: Not returned by AHA-1740A/1742A BIOS Sense Operation Failed: An error occurred issuing the SCSI request sense command to the target.
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A SCSI Read Capacity command is used to determine the maximum logical block of the selected SCSI drive. This information is returned to the host along with the DASD type of the target which will always be 03h for hard disk. AHA-1740A/1742A/1744 Function Status of Operation...
An invalid command error is returned for any of these function codes. Int 15h Functionality After issuing an I/O command to the host adapter, the AHA-1740A/1742A BIOS will make use of the Int 15 Device Busy (function 90h) to inform the operating system that the BIOS is about to wait for a device.
CC000, DC000, EC000, and D0000, the BIOSs will install in the order of CC000, D0000, DC000, and finally EC000. In Standard Mode, you can install a maximum of four AHA-1740A/1742A/1744 host adapter cards. The limiting factor is the number of available ISA DMA channels (5, 6, 7, and 0).
SLBURST* held from BCLK rising Data delay from BCLK rising (write) Data hold from BCLK rising (write) Data held after BCLK rising (read) Data setup to BCLK rising (read) MSTR16* delay from BCLK rising (downshift) nanoseconds AHA-1740A/1742A/1744 Minimum Maximum 45.0 35.0 15.0 25.0 15.0...
Appendix C Register Reference System Register Reference Expansion Board IDs Definition Host ID 0 Host ID 1 Host ID 2 Expansion Board Control BMIC Registers Group 1 Definition I/O Port Address BIOS Address Interrupt Definition SCSI Definition Bus Definition Floppy Definition Reserved 1 Reserved 2 Mailbox Out Byte 0...
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Local Reserved 2 Local Mailbox Out Byte 0 Local Mailbox Out Byte 1 Local Mailbox Out Byte 2 Local Mailbox Out Byte 3 Local Mailbox In Byte 0 Local Mailbox In Byte 1 AHA-1740A/1742A/1744 Signal EISA Slot MBOXIN2 zCDA MBOXIN3 zCDB...
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EISA-to-Fast SCSI Host Adapter Definition Local Mailbox In Byte 2 Local Mailbox In Byte 3 Local Group 2 Control Local Group 2 Status Local Group 2 Interrupt Status Local Group 2 Attention Local Expansion Board Control Local Expansion Board Control Local Data Register Local Index Register Local Control/Status...
Appendix D EISA Free-Form Data SCSI Subsystem Data Structure SCSI Device Byte Reserved 16-47 Bit Definitions Bit 7 - Allow removable media in BIOS disk scan Bit 6 - More than 1 LUN supported Bit 5 - Parity check enable Bit 4 - Send start command Bit 3 - Synchronous negotiation enable Bit 2 - Disconnection enable...
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STOCK NO.: 510208-00 Rev.A GM 3/92 691 south milpitas blvd. milpitas, ca 95035 (408)945-8600 Printed in Singapore...
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