MAA3182SC, MAB3091SC INTELLIGENT DISK DRIVES OEM MANUAL SCSI PHYSICAL SPECIFICATIONS

Transcription

1 MAA3182SC, MAB3091SC INTELLIGENT DISK DRIVES OEM MANUAL SCSI PHYSICAL SPECIFICATIONS

2 FOR SAFE OPERATION Handling of This manual This manual contains important information for using this product. Read thoroughly before using the product. Use this product only after thoroughly reading and understanding especially the section Important Alert Items in this manual. Keep this manual handy, and keep it carefully. FUJITSU makes every effort to prevent users and bystanders from being injured or from suffering damange to their property. Use the product according to this manual. Functional Limitations There may be certain functional limitations concerning the specifications and functions of the products covered by this manual depending on the equipment version, especially concerning the following functions. Versions in which there functions can be used will be communicated through ENGINEERING CHANGE REQUEST/NOTICE, issued by Fujitsu. Function WRITE RAM Command READ RAM Command Equipment Version Which Supports These Functions Equipment Version No. EPROM Version No. Standard INQUIRY Data Product Revision (ASCII) These commands cannot be used in the current version. (Proceed to the Copyright Page) i

3 Related Standards Specifications and functions of products covered by this manual comply with the following standards. Standard (Text) No. Name Enacting Organization ANSI X American National Standard for Information Systems --- Small Computer System Interface (SCSI) American National Standards Institute (ANSI) ANSI X X3T9.2/85-52 Rev 4.B X3T9.2/ Rev 10h X3T D Rev 12 X3T10/1071D Rev 6 American National Standard for Information Systems --- Small Computer System Interface-2 (SCSI-2) COMMON COMMAND SET (CCS) of the Small Computer System Interface (SCSI) DRAFT proposed American National Standard for Information Systems --- Small Computer System Interface-2 (SCSI) DRAFT proposed American National Standard for Information Systems --- SCSI-3 Parallel Interface (Fast-SCSI) DRAFT proposed American National Standard for Information Systems --- SCSI-3 Fast-20 Parallel Interface (Fast20-SCSI) American National Standards Institute (ANSI) American National Standards Institute (ANSI) American National Standards Institute (ANSI) American National Standards Institute (ANSI) American National Standards Institute (ANSI) All Rights Reserved, Copyright 1997 Fujitsu, Limited ii

4 Edition Date published REVISION RECORD Revised contents 01 May.,1997 Specification No.: C141-E038-**EN The contents of this manual is subject to change without prior notice. All Rights Reserved. Copyright 1997 FUJITSU LIMITED iii

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6 PREFACE This manual explains the MAA3182SC and MAB3091SC series 3-1/2" intelligent disk drives each having the built-in SCSI controller. This manual details the specifications and functions of the Small Computer System Interface (SCSI) to connect the above listed disk drives to the user system. Also, the manual details various SCSI command specifications and the command processing functions, and provides the information required to creation of host system software. This manual is intended to be used by the users who have the basic knowledge of computer system operations. The following lists the manual configuration and the contents of each chapter. The caution labels and markings are also explained. Manual Configuration and Contents This manual consists of the following three chapters, and the terminologies and abbreviations sections. Chapter 1 SCSI Bus This chapter describes the configuration, physical and electrical requirements, interface protocol, and other operations of the Small Computer System Interface (SCSI) which connects the MAA3182SC and MAB3091SC series intelligent disk drives to the user system. Chapter 2 SCSI Messages This chapter describes the type and explanation of messages defined for SCSI bus operations. Chapter 3 ERROR Recovery This chapter describes error recovery processing executed by the MAA3182SC and MAB3091SC series intelligent disk drives in response to various errors on the SCSI bus. Glossary This section explains the terminologies the reader must understand to read this manual. Abbreviations This section lists the abbreviated terms and their full words used in this manual. v

7 CONVENTIONS This manual uses the following conventions: NOTE: NOTE indicates the information useful for the user to operate the system. Important information The important information is provided with the "Important" title. The important information text is centered so that the reader can distinguish it from other manual texts. The following gives an example: IMPORTANT The IDD operates as a target (TARG) on the SCSI bus. The IDD is called "TARG" in this chapter except when clear identification is required. Notations A decimal value is indicated as it is in this manual. A hexadecimal value is indicated in the X'17B9' or 17B9h or 17B9H notation. A binary value is indicated in the notation similar to "010." The disk drive model name has a different suffix depending on its SCSI electrical characteristics, capacity, data format used during shipment and others. The following typical model name is used except when the model needs to be distinguished. Also, the disk unit may be referred to as the "IDD" or "unit" in this manual. vi

8 Note 1: Model name M29 0 x S A Format type X:256-byte format (except for the M294x and M295x series) A:512-byte format (except for the M294x and M295x series) B: 1,024-byte format (except for the M294x and M295x series) SCSI type S: Single-ended, 8-bit SCSI (all series) H:Differential, 8-bit SCSI (except M294x and M295x series) Q:Single-ended, 16-bit SCSI (all series) R: Differential, 16-bit SCSI (except M294x and M295x series) C: SCA-1, 16-bit SCSI (M293x series) E: SCA-2, 16-bit SCSI (M294x and M295x series) Heads or 9: 19 heads (M2909) 9: 9 GB (M2949) capacity 3: 13 heads (M2903) 2: 2 GB (M2932, M2952) 5: 15 heads (M2915) 4: 4 GB (M2934, M2954) Device type 0: Full height, large capacity type (M2909 and M2903 series) 1: Full height, high performance type (M2915 series) 3: Full height, large capacity/high performance type (M2934 and M2932 series) 4: Full height, large capacity high performance type (M2948 and M2949 series) 5: 1-inch height, high performance type (M2952 and M2954 series) Note 2: Typical model name Representative Model Name M2909 M2903 M2915 M2934 M2932 M2948 M2949 M2952 M2954 Model Name M2909SX/SA/SB, M2909HX/HA/HB, M2909QX/QA/QB, M2909RX/RA/RB M2903SX/SA/SB, M2903HX/HA/HB, M2903QX/QA/QB, M2903RX/RA/RB M2915SX/SA/SB, M2915HX/HA/HB, M2915QX/QA/QB, M2915RX/RA/RB M2934SX/SA/SB, M2934HX/HA/HB, M2934QX/QA/QB, M2934RX/RA/RB, M2934CX/CA/CB M2932SX/SA/SB, M2932HX/HA/HB, M2932QX/QA/QB, M2932RX/RA/RB, M2932CX/CA/CB M2948S, M2948Q, M2948E M2949S, M2949Q, M2949E M2952S, M2952Q, M2952E M2954S, M2954Q, M2954E Requesting for User's Comments Please use the User's Comment Form attached to the end of this manual to identify user comments including error, inaccurate and misleading information of this manual. Contact to your Fujitsu representative for additional comment forms if required. vii

9 MANUAL ORGANIZATION Product Manual General Description Specifications Data Format Installation Requirements Installation Diagnostics and Maintenance OEM MANUAL SCSI Physical Specifications (This manual) SCSI Bus SCSI Message SCSI Bus Error Recovery Procedure OEM MANUAL SCSI Logical Specifications Command Processing Data Buffer Management Command Specification Sense Data and error Recovery Procedure Disk Medium Management MAINTENANCE MANUAL Specifications and Unit Configuration Diagnostics and Maintenance Troubleshooting and Fault Isolation Removal and Replacement Procedures Theory of Operation viii

10 CONTENTS page CHAPTER 1 SCSI BUS System Configuration Interface Signal Definition Physical Requirements Interface connector Interface cable Electrical Requirements Single-Ended type Differential type Power supply for terminating resistor Signal driving conditions Timing Rule Bus Phases BUS FREE phase ARBITRATION phase SELECTION phase RESELECTION phase INFORMATION TRANSFER phases COMMAND phase DATA phase STATUS phase MESSAGE phase Signal requirements concerning transition between bus phases Time monitoring feature Bus Conditions ATTENTION condition RESET condition Bus Sequence SCAM SCAM operations Ultra SCSI Outline ix

11 Device connection Electrical characteristics of SCSI parallel interface CHAPTER 2 SCSI MESSAGE Message System Message format Message type Message protocol SCSI Pointer Message Explanation COMMAND COMPLETE message: X'00'(T I) SAVE DATA POINTER message: X'02'(T I) DISCONNECT message: X'04' (T I) INITIATOR DETECTED ERROR message: X'05'(I T) ABORT message: X'06' (I T) MESSAGE REJECT message: X'07'(I T) NO OPERATION message: X'08' (I T) MESSAGE PARITY ERROR message: X'09' (I T) LINKED COMMAND COMPLETE message: X'0A'(T I) LINKED COMMAND COMPLETE WITH FLAG message: X'0B'(T I) BUS DEVICE RESET message: X'0C' (I T) ABORT TAG message: X'0D' (I T) CLEAR QUEUE message: X'0E'(I T) TERMINATE I/O PROCESS message: X'11' (I T) CONTINUE I/O PROCESS message: X'12' (I T) TARGET TRANSFER DISABLE message: X'13' (I T) QUEUE TAG messages IDENTIFY message: X'80' to X'FF' (I T) SYNCHRONOUS DATA TRANSFER REQUEST message(i T) WIDE DATA TRANSFER REQUEST message (I T) CHAPTER 3 ERROR RECOVERY Error Conditions and Retry Procedure Recovery Control x

12 Glossary... GL - 1 Abbreviation... AB - 1 xi

13 FIGURES page 1.1 Example of SCSI configuration Interface signals DATA BUS and SCSI ID SCSI interface connector (IDD side) (8-bit SCSI) SCSI interface connector (cable side) (8-bit SCSI) Single-Ended connector pin assignments (8-bit SCSI) Differential connector pin assignments (8-bit SCSI) SCSI interface connector (IDD side) (16-bit SCSI) SCSI interface connector (cable side) (16-bit SCSI) Single-ended connector pin assignment (16-bit SCSI) Differential connector pin assignment (16-bit SCSI) SCA type, single-ended 16-bit SCSI interface connector (IDD side) SCA Type, single-ended 16-bit SCSI interface connector (cable side) SCA Type, single-ended 16-bit SCSI connector signal assignment Connection of interface cable Single-Ended SCSI termination circuit Single-Ended SCSI termination circuit Differential SCSI termination circuit Differential type driver protection circuit Single-ended terminating resistor circuit BUS FREE phase ARBITRATION phase SELECTION phase RESELECTION phase INFORMATION TRANSFER phase (phase control) Transfer in asynchronous mode Transfer in synchronous mode Transfer in Fast synchronous mode Data sequence at data transfer Data transfer rate in asynchronous mode Data transfer rate in synchronous mode Switching direction of transfer over data bus xii

14 1.33 ATTENTION condition RESET condition Bus phase sequence Example of bus phase transition at execution of a single command State of level-1 SCAM target State of level-2 SCAM target Comparison of active negate current and voltage Unbalanced test circuit Termination of differential signal device Protection circuit of unbalanced driver Message format SCSI pointer configuration xiii

15 TABLES page 1.1 INFORMATION TRANSFER phase identification Interface cable requirements Requirements for terminating resistor power supply Signal status Signal driving method Bus phases and signal sources Timing specifications Parameters used for fast synchronous data transfer mode Retry count setting for RESELECTION phase SCSI bus timing values SCSI message Extended message Definition of data transfer mode by message exchange Synchronous mode data transfer request setting Transfer mode setup request from INIT to IDD Transfer mode setup request from IDD to INIT Data bus width defined by message exchange Wide mode setting request from the INIT to the IDD Wide mode setting request from the IDD to the INIT Retry procedure for SCSI error xiv

16 CHAPTER 1 SCSI BUS 1.1 System Configuration 1.2 Interface Signal Definition 1.3 Physical Requirements 1.4 Electrical Requirements 1.5 Timing Rule 1.6 Bus Phases 1.7 Bus Conditions 1.8 Bus Sequence 1.9 SCAM 1.10 Ultra SCSI This chapter describes the configuration, physical and electrical characteristics, interface protocol, and operations of SCSI buses. Note: The IDD operates as a target (TARG) on the SCSI bus. The IDD is called "TARG" in this chapter except when clear identification is required. 1.1 System Configuration Up to eight 8-bit SCSI series models (including the M2909s/H, M2903S/H, M2915S/H, M2934S/H, M2932S/H, M2948S, M2949S, M2952S, and M2954S series) can be connected to the system via the SCSI buses. Also, up to bit SCSI series models (including the M2909Q/R, M2903Q/R, M2915Q/R, M2934Q/R/C, M2932Q/R/C, M2948Q/E, M2949Q/E, M2952Q/E, and M2954Q/E series) can be connected to the system via the SCSI buses. Figure 1.1 gives an example of multi-host system configuration. Each SCSI unit operates as an initiator (INIT) or a target (TARG). Only a single INIT and a single TARG selected by this INIT can operate simultaneously on the SCSI bus. The system configuration allows any combination of a SCSI unit to operate as the INIT and a SCSI unit to operate as the TARG. Also, any unit having both the INIT and TARG functions can be used on the SCSI bus. Each SCSI unit is assigned a unique address (or SCSI ID). The SCSI ID corresponds to a bit number of the SCSI data bus. While the INIT uses a logical unit number (LUN) to select an I/O unit to be connected under TARG control. 1-1

17 Any SCSI ID of the IDD can be selected using the setup pins. However, the LUN is fixed to zero (0). The SCSI ID can be 0 to 7 for the 8-bit SCSI system, and it can be 0 to 15 for the 16- bit SCSI system. Note: The maximum number of SCSI units and the maximum cable length are limited depending on the selected SCSI data transfer mode and the SCSI transceiver type. Appropriate SCSI units and cable length must be determined for each system. Figure 1.1 Example of SCSI configuration 1-2

18 1.2 Interface Signal Definition Figure 1.2 shows interface signal types. The SCSI buses consists of 18 signal lines (for 8-bit SCSI system) or 27 signal lines (for 16-bit SCSI system). The 18 signal lines consist of data buses such as M290XS/H, M291XS/H, M293XS/H, M294XS and M295Xs (1 byte plus odd parity bits) or M290XQ/R, M291XQ/R, M293XQ/R/C, M294XQ/E and M295XQ/E (2 types plug two odd parity bits), and 9 control signal lines. The SCSI bus can be a single-ended or differential interface depending on the model used. Their physical and electrical characteristics are detailed in Sections 1.3 and 1.4. Figure 1.2 Interface signals 1-3

19 (1) DB7 to DB0, P/DB15 to P/DB00, P1, P0 (Data buses) The 8-bit SCSI system uses a bidirectional data bus consisting of one-byte data and an odd parity bit. While the 16-bit SCSI system uses a bidirectional data bus consisting of two-byte data and two odd parity bits. MSB (2 7 ): DB7, LSB (2 0 ): DB0 MSB (21 5 ): DB15, LSB (2 0 ): DB00 The data bus is used to transfer a command, data, status, or a message in the INFORMATION TRANSFER phase. However, DB15 to DB08 and DBP1 are used for data transfer only. The data is transferred only after the WIDE DATA TRANSFER REQUEST message has been exchanged and the 16-bit data transfer mode has been established between the INIT and TARG. In the ARBITRATION phase, the data bus is used to send a SCSI ID to determine the bus arbitration priority. In the SELECTION or RESELECTION phase, the data bus is used to send a SCSI ID of the INIT and TARG. Figure 1.3 shows the relationship between the data buses and SCSI IDs. Figure 1.3 DATA BUS and SCSI ID Data bit "n" is equal to logical 1 when the DB(n) signal is true. It is equal to logical 0 when the DB(n) is false. The parity bits (DBP, or DBP1 and DBP0) is optional for the system. The IDD handles the data bus parity as follows: The IDD has the data bus parity check function, and can enable or disable the parity check. See Section "SCSI Parity" of the Product Manual for setup details. When valid data is sent to the data bus from the IDD, the parity data is always guaranteed except for the ARBITRATION phase. 1-4

20 (2) BSY (BUSY) The BSY signal indicates that the SCSI bus is in use. In the ARBITRATION phase, this signal is used to request for the bus usage priority. (3) SEL (SELECT) The SEL signal is used by the INIT to select a TARG (in the SELECTION phase) or by the TARG to reselect an INIT (in the RESELECTION phase). (4) C/D (CONTROL/DATA) This is a combination of I/O and MSG signals, and specifies a type of information transferred on the data bus. The C/D signal is always driven by the TARG (see Table 1.1). (5) I/O (INPUT/OUTPUT) The I/O signal specifies the information transmission direction on the data bus. It is also used to identify the SELECTION phase or RESELECTION phase. This signal is always driven by the TARG (see Table 1.1). (6) MSG (MESSAGE) The MSG signal indicates that a "message" transmission is in progress on the data bus. It is always driven by the TARG (see Table 1.1). Table 1.1 INFORMATION TRANSFER phase identification C/D I/O MSG DB7-0, P Direction Phase Data INIT TARG DATA OUT Data INIT TARG DATA IN Command INIT TARG COMMAND Status INIT TARG STATUS not used not used Message INIT TARG MESSAGE OUT Message INIT TARG MESSAGE IN 1-5

21 (7) REQ (REQUEST) This is a transmission request from the TARG to the INIT in the INFORMATION TRANSFER phase. (8) ACK (ACKNOWLEDGE) The ACK signal is a response to the REQ signal sent from the INIT to TARG in the INFORMATION TRANSFER phase. (9) ATN (ATTENTION) The ATN signal indicates that the INIT has a message to be sent to the TARG. It is used to generate an ATTENTION condition. (10) RST (RESET) The RST signal is a Reset signal to clear all SCSI units on the bus (to the RESET condition). 1.3 Physical Requirements All SCSI units are connected to each other in a daisy chain. Both ends of the interface cable are terminated with resistor. The following defines the SCSI bus electrical characteristics (for interface signal driver/receiver) of the M290x, M291x, M293x, M294x, and M295x series. Single-ended (Unbalanced transmission type): Maximum cable length: 6 m For 16-bit SCSI bus (M290xQ, M291xQ, M293xQ/C, M294xQ/E, and M295xQE series): Maximum cable length: 6 m (at 10 MBps or less transmission rate) Maximum cable length: 3 m (at 10 MBps or less transmission rate) Differential (balanced transmission) type: Interface connector (1) Interface connector of 8-bit SCSI The 8-bit SCSI bus connectors of the IDD (the M290xS/H, M291xS/H, M293xS/H, M294xS/H and M295xS series) are 50-pin, unshielded connectors, each having two rows of 25 parallel pins (separated 2.54 mm or 0.1" from each other) (see Figure 1.4). Use the 50-pin, unshielded pin socket, having two rows of 25 parallel pins (separated 2.54 mm or 0.1" from each other). Also, a keyed connector (with a band) to prevent an incorrect cable insertion is desirable to use (see Figure 1.5). 1-6

22 Figures 1.6 and 1.7 show the standard pin assignment of single-ended and differential interface connectors. Figure 1.4 SCSI interface connector (IDD side) (8-bit SCSI) 1-7

23 Figure 1.5 SCSI interface connector (cable side) (8-bit SCSI) 1-8

24 Pin No. Signal Signal Pin No. 01 GND -DB GND -DB GND -DB GND -DB GND -DB GND -DB GND -DB GND -DB GND -DBP GND GND GND GND (reserved) (reserved) (open) TERMPWR* (reserved) (reserved) GND GND GND -ATN GND GND GND -BSY GND -ACK GND -RST GND -MSG GND -SEL GND -C/D GND -REQ GND -I/O 50 *: Power supply for terminator (selectable by jumper: input only, input/output, or open) Figure 1.6 Single-Ended connector pin assignments (8-bit SCSI) 1-9

25 Pin No. Signal Signal Pin No. 01 GND GND DB0 -DB DB1 -DB DB2 -DB DB3 -DB DB4 -DB DB5 -DB DB6 -DB DB7 -DB DBP -DBP DIFFENS(*1) GND (reserved) (reserved) TERMPWR(*2) TERMPWR(*2) (reserved) (reserved) ATN -ATN GND GND BSY -BSY ACK -ACK RST -RST MSG -MGS SEL -SEL C/D -C/D REQ -REQ I/O -I/O GND GND 50 *1 Differential Driver protection signal *2 Terminating resistor power (jumper selectable: For input only, for input and output, or open) Figure 1.7 Differential connector pin assignments (8-bit SCSI) 1-10

26 (2) Interface connector of the 16-bit SCSI The IDD 16-bit SCSI bus connector (M290xQ/R, M291xQ/R, M293xQ/R, M294xQ, and M295xQ series) is nonshielded 68-pin, consisting of two 34-pin rows with adjacent pins 1.27 mm (0.05 inch) part (Figure 1.8). For the interface cable connector, use a nonshielded 68-contact socket consisting of two 34- contact rows points with adjacent contact points 1.27 mm (0.05 inch) apart (Figure 1.9). Figures 1.10 and 1.11 show single-ended and differential interface connector signal assignment. Figure 1.8 SCSI interface connector (IDD side) (16-bit SCSI) 1-11

27 Figure 1.9 SCSI interface connector (cable side) (16-bit SCSI) 1-12

28 Pin No. Signal Signal Pin No. 01 GND -DB GND -DB GND -DB GND -DB GND -DBP GND -DB GND -DB GND -DB GND -DB GND -DB GND -DB GND -DB GND -DBP GND -DBP GND GND GND GND TERMPWR * TERMPWR * TERMPWR * TERMPWR * (reserved) (reserved) GND GND GND -ATN GND GND GND -BSY GND -ACK GND -RST GND -MSG GND -SEL GND -C/D GND -REQ GND -I/O GND -DB GND -DB GND -DB GND -DB11 68 * Terminating resistor power Figure 1.10 Single-ended connector pin assignment (16-bit SCSI) 1-13

29 Pin No. Signal Signal Pin No. 01 +DB12 -DB DB13 -DB DB14 -DB DB15 -DB DBP1 -DBP GND GND DB00 -DB DB01 -DB DB02 -DB DB03 -DB DB04 -DB DB05 -DB DB06 -DB DB07 -DB DBP0 -DBP DIFFSENS (*1) GND TERMPWR (*2) TERMPWR (*2) TERMPWR (*2) TERMPWR (*2) (reserved) (reserved) ATN -ATN GND GND BSY -BSY ACK -ACK RST -RST MSG -MSG SEL -SEL C/D -C/D REQ -REQ I/O -I/O GND GND DB08 -DB DB09 -DB DB10 -DB DB11 -DB11 68 *1 Differential Driver protection signal *2 Terminating resistor power Figure 1.11 Differential connector pin assignment (16-bit SCSI) 1-14

30 (3) Interface connector of SCA type 16-bit SCSI The 16-bit, SCA-type SCSI bus connectors of the IDD (M293xC, M293xE, and M295xE series) are 80-pin, unshielded connectors, each having two rows of 40 parallel pins (separated 1.27 mm or 0.05" from each other) (see Figure 1.12). Use the 80-pin, unshielded connectors, each having two rows of 40 parallel pins (separated 1.27 mm or 0.05" from each other) (see Figure 1.13). Figure 1.14 shows the pin assignment of 16-bit, SCA-type single-ended SCSI interface connector. Figure 1.12 SCA type, single-ended 16-bit SCSI interface connector (IDD side) 1-15

31 T.B.D Figure 1.13 SCA Type, single-ended 16-bit SCSI interface connector (cable side) 1-16

32 Pin No. Signal Signal Pin No V (CHARGE) 12V RETURN (GND) V 12V RETURN (GND) V 12V RETURN (GND) V 12V RETURN (MATED1) reserved (N.C.) reserved (N.C.) reserved (N.C.) reserved (N.C.) DB11 GND DB10 GND DB09 GND DB08 GND I/O GND REQ GND C/D GND SEL GND MSG GND RST GND ACK GND BSY GND ATN GND DBP0 GND DB07 GND DB06 GND DB05 GND DB04 GND DB03 GND DB02 GND DB01 GND DB00 GND DBP1 GND DB15 GND DB14 GND DB13 GND DB12 GND V 5V RETURN (MATED2) V 5V RETURN (GND) V (CHARGE) 5V RETURN (GND) SPINDLE SYNC -LED RMT START DLYD START SCSI ID0 SCSI ID SCSI ID2 SCSI ID3 80 Note: Signal in parentheses indicates for SCA-2 type. Figure 1.14 SCA Type, single-ended 16-bit SCSI connector signal assignment 1-17

33 1.3.2 Interface cable Use the twisted-pair interface cables satisfying the requirements of Table 1.2. Table 1.2 Interface cable requirements Conductor size 8-bit SCSI Single-ended/ differential 16-bit SCSI Single-ended Differential 28 AWG or larger Characteristic impedance Maximum Minimum 132 Ω 90 Ω Impedance difference between signal lines Maximum 12 Ω Maximum 20 Ω Signal line propagation delay time Propagation delay time difference of signal line Signal attenuation Maximum 0.20 ns/m Maximum 5.4 ns/m Maximum 0.15 ns/m Maximum db/m at 5 MHz DC resistance Maximum Ω/m at 20 C A twisted-pair cable must consist of pin n and pin n+1 (where "n" is an odd number) of the interface connector. Use the SCSI bus cables having the same impedance characteristics to minimize the signal reflection but keep the highest possible transmission characteristics. If SCSI units are connected to the terminals other than the interface cable ends, use the cable branch at the SCSI connectors. No more SCSI cable can be connected to the last SCSI unit (which is connected to the SCSI bus) except when it is terminated with the terminator (see Figure 1.15). The interface cable must have the stub length less than 0.1 meter for the single-ended SCSI cable, or less than 0.2 meter for the differential SCSI cable. Separate the stabs at least 0.3 meter from each other. (Keep the stab at least 30 cm away from a SCSI unit.) 1-18

34 (a) Connection to a middle point of the cable (b) Connection to the end of the cable. Figure 1.15 Connection of interface cable 1-19

35 1.4 Electrical Requirements Single-Ended type (1) Termination circuit All signals except for RESERVE, GND, or TERMPWR should be terminated at both ends of the bus. Each signal should be terminated by one of the following methods. Figures 1.16 and 1.17 show the termination circuit. a) Each signal must connect to the TERMPWR signal through 220 Ω (within ±5%) resistor, and connect to ground through 330 Ω (within ±5%) resistor. b) The termination circuit of each signal shall satisfy the following conditions. 1) A characteristics impedance of the termination circuit should be within a range between 100 to 132 Ω. 2) The terminator circuit shall be powered from the TERMPWR line or from others. However, the circuit shall be able to operate without any additional power. 3) When the driver circuit asserts a signal line and its voltage becomes 0.5 VDC, any current flowed in the driver circuit should not exceed 48 ma, and the current flowed from two termination circuit should be 44.8 ma. 4) When a signal is released, the voltage of a signal should be at least 2.5 V when the TERMPWR line satisfies the specification (see Subsection 1.4.3). 5) If the TREMPWR is supplied from at least one SCSI unit in the correct target/initiator configuration, the above listed requirements shall be satisfied. Figure 1.16 Single-Ended SCSI termination circuit-1 The IDD uses the terminator circuit satisfying conditions (b) above. The INIT terminator circuit is also recommended to meet conditions (b) above. 1-20

36 Figure 1.17 Single-Ended SCSI termination circuit

37 (2) Driver and receiver For the interface signal driver, an open-collector or tri-state buffer that satisfies the following output characteristics is used. All signals are negative logic (true = "L"). The receiver and non-driver of the SCSI device under the power-on state should satisfy the following input characteristics on each signal. [Output characteristic] V OL = 0.0 to 0.50 VDC (@ I OL = 48 ma) V OH = 2.5 to 5.25 VDC [Input characteristics] V IL = 0.0 to 0.80 VDC V IH = 2.0 to 5.25 VDC I IL = -0.4 to 0.0 ma (@ V I = 0.5 VDC) I IH = 0.0 to 0.1 ma (@ V I = 2.7 VDC) Input hysteresis = 0.2 VDC min. Input capacity = 25 pf max. Note: The SCSI device under the power-off state should satisfy the characteristics of I IL and I IH. [Recommended circuit example] Driver: MB463 (Fujitsu) or SN7438 (TI) (Open-collector NAND gate) Receiver: SN74LS240 or SN74LS19 (TI) (Shumitt trigger input inverter) Differential type (1) Termination circuit All signals except for RESERVE, GND, or TERMPWR should be terminated at both ends of the bus. The resistor tolerance shall be within ±5%. Figure 1.18 shows a differential terminator circuit. 1-22

38 Figure 1.18 Differential SCSI termination circuit (2) Driver and receiver The electrical characteristics of driver and receiver for interface signals must satisfy the ISO 8482 (EIA standard: RS ) and the following I/O requirements: [Output characteristic driver] V OL = 1.7 VDC max. (@ I OL = +55 ma) V OH = 2.7 VDC min. (@ I OH = -55 ma) V OD = 1.0 VDC min.( V OH - V OL : differential common mode voltage = 7 to +12 VDC) Note: V OL and V OH are shall be equal to the signal ground (SG) of the driving SCSI unit. [Input characteristics: receiver and non-driver] I I = ±2.0 ma max. (positive and negative input voltage range: 7 to +12 VDC) Input hysteresis = 35 mvdc min. Input capacitance = 25 pf max. Note: Any passive drive and the SCSI devices with power off must also satisfy the characteristic of I I. 1-23

39 (3) Driver protection circuit The drive enable signal of the driver circuit is generated from the DIFFENS signal of the differential interface connector (see Figure 1.19). If a single-ended SCSI unit or a terminating resistor is incorrectly connected, this pin is grounded and the driver circuit is stopped from driving. Figure 1.19 Differential type driver protection circuit Power supply for terminating resistor The TERMPWR signal of the interface connector supplies the power to the terminating resistor circuit connected to both ends of the cable. To attach a terminating resistor to an external SCSI unit or to cut the power of SCSI unit having a terminator, the terminator power must be supplied to the TERMPWR line from any of SCSI units of the bus. The SCSI unit (such as a host adapter) which always operates as the INIT should supply the power. The terminating resistor power shall be supplied to the TERMPWR line through a diode to prevent a reverse current. Table 1.3 lists the requirements for terminating the resistor power supply (Vterm). Table 1.3 Requirements for terminating resistor power supply Single-ended type Differential type Output voltage 4.25 to 5.25 VDC 4.00 to 5.25 VDC Current capacity 900 ma min. 600 ma min. Sink current 1.0 ma max. 1.0 ma max. Figure 1.20 shows the configuration of a single-ended SCSI terminating resistor circuit. The circuit shall be set in either mode (by the CN7 setup pin) depending on the IDD system requirements. As the single-ended circuit does not have the terminating resistor, a terminator is required when connected to the SCSI interface end. 1-24

40 8-bit SCSI setting terminal (CN7) 16-bit SCSI setting terminal (CN10) Connection of terminating resistor circuit Terminating resistor circuit connected *Short *Short *Short The terminating resistor circuit is not connected. Open Open Open Only terminating resistor circuit for DB15-DB8, DBP1 is connected (16-bit mode) Open Short Figure 1.20 Single-ended terminating resistor circuit 1-25

41 1.4.4 Signal driving conditions (1) Signal status value Table 1.4 shows the correspondence between the input interface signal level at the receiving end and its logic state. Table 1.4 Signal status Logic state Logic state Logic state (at receiving end) Single-ended type Differential type True, "1", or asserted Low (0.0 to 0.8 VDC) + signal level >-signal level False, "0", negated or released High (2.0 to 5.25 VDC) -signal level > + signal level (2) Signal driving method Two driving methods are available: "OR-tied" type and "non-or-tied" type as indicated in Table 1.5. Table 1.5 Signal driving method Driving method "OR-tied" type "non-or-tied" type Signal status False (*1) No SCSI device drives a signal. The signal becomes false when the terminating resistor circuit is biased. A particular SCSI device drives the signal false. Otherwise, no SCSI device drives the signal. True An SCSI device drives the signal true *1 In this manual, the signal is said to be false if one of the following conditions is satisfied. 1. The signal is actually driven by an SCSI device to become false (non-or-tied type). 2. No SCSI device is driving the signal (OR-tied type or non-or-tied type). If the BSY and RST signals may be driven by two or more SCSI units simultaneously in the interface operating sequence, they must be driven in the OR-tied method. All signals except for BSY, RST and DBP are not driven by multiple SCSI units simultaneously. The BSY and RST signals can be driven in any of OR-tied and non-or-tied methods. However, the DBP signals (DBP0 and DBP1) must be driven false in the ARBITRATION phase. All signals driven in OR-tied and non-or-tied method can be mixed on the same signal line of SCSI bus except for BSY and RST signals. 1-26

42 (3) Signal sources Table 1.6 lists SCSI unit types (or signal sources) which can drive signals in each interface operating phase. Table 1.6 Bus phases and signal sources Bus phase Signal BSY SEL I/O C/D NSG REQ ACK DB7-0, DBP0 DB15-0, DBP0, 1 ANT BUS FREE N N N N N N N N N A ARBITRATION A W N N N N ID ID N A SELECTION I&T I N N N N I I I A RESELECTION I&T T T N N N T T I A SETUP T N T T T I I or T I or T I A COMMAND T N T T T I I I I A DATA IN T N T T T I T T I A DATA OUT T N T T T I I I I A STATUS T N T T T I T T I A MESSAGE IN T N T T T I T T I A MESSAGE OUT T N T T T I I I I A RST A: Any SCSI unit can drive the signal. Also, two or more SCSI units may drive the signal simultaneously. I: Only the INIT SCSI unit drives the signal. I&T: I or T: ID: The INIT and TARG SCSI units drive the signal in the interface operating sequence. INIT, TARG or both can drive this signal according to the interface sequence. The INIT or TARG SCSI unit (or both units) may drive the signal depending on the I/O signal status and bus width. Each SCSI device which is actively arbitrating the bus drives a unique data bit (SCSI ID). The parity bit may be undriven or driven to the true state, but must never be driven to the false state. N: Not be driven by any SCSI device. T: Only the TARG SCSI unit drives the signal. W: Only a single SCSI unit selected through arbitration drives the signal. 1-27

43 1.5 Timing Rule Table 1.7 gives the timing required for operations on the SCSI bus. Table 1.7 Timing specifications (1 of 3) No. Name Standard Timing specification 1 Arbitration Delay 2 Assertion Period 3 Bus Clear Delay Min. 2.4 µs Min. 90 ns Max. 800 ns The minimum wait period between the time the SCSI device sends a BSY signal and the time the value on the DATA BUS for determining the priority of bus use is judged in the ARBITRATION phase. Maximum time is not defined. Minimum pulse width of an ACK signal sent by INIT and an REQ signal sent by TARG for synchronous data transfer. Maximum allowable period between the time either of the following events occurs and the time the SCSI device stops driving all bus signals. 1. Detection of the BUS FREE phase (when both BSY and SEL signal become false during Bus Settle Delay). Note: 4 Bus Free Delay Min. 800 ns Maximum allowable period between the time both BSY and SEL signal became false and the time the bus is released is 1200 ns. An SCSI device that requires a period longer than Bus Settle Delay for the detection of the BUS FREE phase must release the bus within (Bus Clear Delay) minus (Bus Settle Delay excess time). 2. Another SCSI device asserts the SEL signal during an ARBITRATION phase. 3. The RST signal becomes TRUE (RESET condition). Minimum wait period between the time the SCSI device detects a BUS FREE phase and the time it sends a BSY signal to initiate an ARBITRATION phase. 5 Bus Set Delay Min. 1.8 µs Maximum allowable period between the time an SCSI device detects a BUS FREE phase and the time its sends BSY and SCSI ID signals to initiate an ARBITRATION phase. 6 Bus Settle Delay 7 Cable Skew Delay 8 Data Release Delay Min. 400 ns Max. 10 ns Max. 400 ns Minimum wait period between the time a particular control signal condition changes and the time the bus condition is stabilized. Maximum allowable difference in transmission time over the interface cable between any two bus signals from any two SCSI devices. Maximum allowable period between the time an I/O signal changes its status from false to true and the time the INIT stops driving DATA BUS signals. 1-28

44 Table 1.7 Timing specifications (2 of 3) No. Name Standard Timing specification 9 Deskew Delay Min. 45 ns Time for compensation for skew involved in bus signal transmission. 10 Disconnection Delay Min. 200 µs The minimum waiting time from the TARG releases the BSY signal after receiving the DISCONNECT message from the INIT to the TARG enters the ARBITRATION phase. 11 Hold Time Min. 45 ns In synchronous data transfer mode, the minimum time during which the transfer data on the DATA BUS from the leading edge of the REQ or ACK signal pulse must be maintained to compensate for the hold time in the SCSI device receiving data. 12 Negation Period 13 Power-On to Selection Time 14 Reset to Selection Time 15 Reset Hold Time 16 Selection Abort Time 17 Selection Timeout Delay 18 Transfer Period Min. 90 ns Max. 10 sec [Recommended value] Max. 250 sec [Recommended value] Min. 25 µs Max. 200 µs Min. 250 ms [Recommended value] In synchronous data transfer mode, the minimum time from the trailing edge of an REQ signal to the leading edge of the next REQ signal or from the trailing edge of an ACK signal to the leading edge of the next ACK signal. Maximum time from the TARG is turned on to the TARG can post the correct status and sense data for the TEST UNIT READY, INQUIRY or REQUEST SENSE command. Maximum time from the RESET condition (hard RESET) is released to the TARG can post the correct status and sense data for the TEST UNIT READY, INQUIRY or REQUEST SENSE command. The minimum time during which the RST signal must be held true to create a RESET condition. Maximum time is not defined. In a SELECTION or RESELECTION phase, the maximum allowable period between the time the SCSI device recognizes itself as selected and the time it replies a BSY signal. In a SELECTION or RESELECTION phase, the minimum time during which the INIT or TARG waits for a BSY signal from the SCSI device to be selected before it initiates time-out processing. In synchronous data transfer mode, the minimum time (minimum repetition time) from the leading edge of an REQ signal to the leading edge of the next REQ signal or from the leading edge of an ACK signal to the leading edge of the next ACK signal. The actual value is defined using a SYNCHRONOUS DATA TRANSFER REQUEST message exchanged between the INIT and TARG. 1-29

45 Table 1.7 Timing specifications (3 of 3) No. Name Standard Timing specification 19 Fast Assertion Period 20 Fast Cable Skew Delay 21 Fast Deskew Delay 22 Fast Hold Time 23 Fast Negation Period Min. 30 ns Max. 5 ns Min. 20 ns Min. 10 ns Min. 30 ns This value is the minimum time that a TARG shall assert REQ while using fast synchronous data transfers. It is also, the minimum time that an INIT shall assert ACK while using fast synchronous data transfers. This value is the maximum difference in propagation time allowed between any two SCSI bus signals measured between any two SCSI devices while using fast synchronous data transfers. This value is the minimum time required for deskew of certain signals while using fast synchronous data transfers. This value is the minimum time added between the assertion of REQ or ACK and the changing of the data lines to provide hold time in the INIT or TARG, respectively, while using fast synchronous data transfers. This value is the minimum time that a TARG shall negate REQ while using fast synchronous data transfers. Also, the minimum time that an INIT shall negate ACK while using fast synchronous data transfers. 1.6 Bus Phases The SCSI bus must be in one of the following eight phases: BUS FREE phase ARBITRATION phase SELECTION phase RESELECTION phase COMMAND phase DATA phase STATUS phase MESSAGE phase INFORMATION TRANSFER phase The SCSI bus can never be in more than one phase at any given time. Note: In the following bus phase conditions, signals are false unless otherwise defined. Signals on the timing charts are assumed to be positive logic (or active high). 1-30

46 1.6.1 BUS FREE phase All SCSI units do not use the bus in the BUS FREE phase. SCSI units shall detect the BUS FREE phase after SEL and SBY signals are both false for at least 400 ns (Bus Settle Delay). SCSI units which have detected the BUS FREE phase shall release all bus signals within 800 ns (Bus Clear Delay) after BSY and SEL signals become false for 400 ns (Bus Settle Delay). If a SCSI unit requires more than 400 ns (Bus Settle Delay) to detect the BUS FREE phase, it shall release all bus signals within the following period (t): t = 800 ns (Bus Clear Delay) - (Period required for BUS FREE phase detection) ns (Bus Settle Delay) The maximum time allowed for releasing the bus after both SEL and BSY becomes false is 1,200 ns (Bus Settle Delay + Bus Clear Delay). Figure 1.21 shows the BUS FREE phase. Figure 1.21 BUS FREE phase 1-31

47 The SCSI bus enters the BUS FREE phase when the TARG stops the BSY signal in one of the following events: When RESET condition has been detected When the TARG has received the ABORT message normally When the TARG has received the BUS DEVICE RESET message normally When the TARG has sent the DISCONNECT message normally When the TARG has sent the COMMAND COMPLETE message normally When the TARG has received the ABORT TAG message normally When the TARG has received the CLEAR QUEUE message normally If a SELECTION or RESELECTION phase is terminated unsuccessfully, the SCSI bus enters the BUS FREE phase. This BUS FREE phase is generated when the SEL signal becomes false. In any case other than above, if the TARG negates the BSY signal to enter a BUS FREE phase, the TARG informs the INIT that it has detected an ERROR condition of the SCSI bus. The TARG can enter a BUS FREE phase forcibly regardless of ATN signal status; the INIT must treat that phase transition as indicating the abnormal end of command. The TARG clears all hold data or status and terminates the command being executed. It can then create sense data indicating the detailed error condition. If the INIT detects a BUS FREE phase when it is not expected, it should issue a REQUEST SENSE command to read the sense data ARBITRATION phase The ARBITRATION phase allows one SCSI unit to gain control of the SCSI bus so that an INIT starts the SELECTION phase. This is an optional system bus phase. This phase is required for the system that has two or more INITs or uses the RESELECTION phase. Figure 1.22 shows the ARBITRATION phase, and the following explains how the SCSI unit gets control of the SCSI bus. 1) The SCSI device shall wait for BUS FREE phase. (see Section 1.6.1). 2) The SCSI device shall wait at least 800 ns (Bus Free Delay) after the BUS FREE phase detection. 3) Then the SCSI device that arbitrates the bus asserts the DATA BUS bit corresponding to its own SCSI ID and BSY signal (*1) within 1.8 µs (Bus Set Delay) after last observation of the BUS FREE phase. 4) After waiting at least 2.4 µs (ARBITRATION Delay) since the SCSI device asserted BSY signal, the SCSI device shall examine the value on the DATA BUS to determine the priority of the bus arbitration (*1). 1-32

48 Bus arbitration priority: DB7 (ID#7) > DB6 (ID#6) >... >DB0 (ID#0) >DB15 (ID#15) >DB14 (ID#14) >... >DB8 (ID#8) When the SCSI device detects any ID bit which is assigned higher priority than its own SCSI ID, the SCSI device shall release its signals (BSY and its SCSI ID) then may return to step (1). (The SCSI device #1 in Figure 1.22 has lost the arbitration.) The SCSI device which detects no higher SCSI ID bit on the DATA BUS can obtain the bus control, then it shall assert SEL signal. (The SCSI device #7 in Figure 1.22 has won the arbitration.) Any other SCSI device that is participating in the ARBITRATION phase shall release its signals within 800 ns (Bus Clear Delay) after SEL signal becomes true, then may return to step (1). (The SCSI device #3 in Figure 1.22 has lost the arbitration.) 5) The SCSI device which wins arbitration (SCSI device #7 in Figure 1.22) shall wait at least 1.2 µs (Bus Clear Delay + Bus Settle Delay) after asserting SEL signal before changing any signal state. *1: When an SCSI device sends its SCSI ID to the DATA BUS, it asserts only the bit at the position corresponding to its own ID and leaves the other seven (or fifteen) bits false. The parity bit (DBP, DBP0 or DBP1 signal) is not driven or driven true, rather than false. The parity bit on the DATA BUS is unpredictable during an ARBITRATION phase. 1-33

49 Figure 1.22 ARBITRATION phase 1-34

50 1.6.3 SELECTION phase An INIT selects a TARG (a single SCSI unit) in the SELECTION phase. Note: I/O signal is false during a SELECTION phase. (The I/O signal identifies the phase as SELECTION or RESELECTION). (1) Start sequence without ARBITRATION phase In systems with the ARBITRATION phase not implemented, the INIT starts the SELECTION phase in the following sequence (see Figure 1.23). 1) The INIT shall wait for at least 800 ns (Bus Clear Delay) after BUS FREE phase detection. 2) Then the INIT asserts SCSI IDs of desired TARG and INIT itself on the DATA BUS. Note: It single INIT operates without the RESELECTION phase, it is allowed to assert only the TARG's SCSI ID. 3) After waiting at least 90 ns (Deskew Delay 2), the INIT asserts SEL signal and waits the response (BSY signal) from the TARG. (2) Start sequence with ARBITRATION phase In systems with ARBITRATION phase implemented, the INIT starts the SELECTION phase in the following sequence (see Figure 1.23). 1) The INIT shall wait for at least 1.2 µs (Bus Clear Delay + Bus Settle Delay) after turning SEL signal on during the ARBITRATION phase. 2) Then the INIT asserts SCSI IDs of the desired TARG and INIT itself on the DATA BUS. Note: If single INIT operates without RESELECTION phase, it is allowed to assert only the TARG's SCSI ID. 3) The INIT releases BSY signal after waiting at least 90 ns (Deskew Delay 2). The INIT shall then wait at least 400 ns (Bus Settle Delay) before looking for the response (BSY signal) from the TARG. 1-35

51 (3) Response sequence If an SCSI device (TARG to be selected) detects its SCSI ID bit on the DATA BUS when the SEL signal is true and both BSY and I/O signals are false for at least 400 ns (Bus Settle Delay), the SCSI device shall recognize that it is selected in the SELECTION phase. At this time, the selected TARG may sample all bits on the SCSI bus to identify the INIT's SCSI ID. The TARG must response to the INIT by asserting the BSY signal within 200 µs (Selection Abort Time) from the TARG detects that the TARG is selected. If the SCSI ID with three or more bits is detected, or if a parity error is detected under the system that the parity bit is enabled, the TARG shall not respond to the SELECTION phase. At least 90 ns (Deskew Delay 2) after the BSY signal (asserted by the TARG) detection, the INIT shall release SEL signal. The values on the DATA BUS can be changed after this time. (4) Timeout procedure If the INIT cannot detect the response from TARG when the Selection Timeout Delay (recommended: 250 ms) or longer has passed after starting the SELECTION phase, the timeout procedure shall be performed through one of the following schemes: The INIT asserts the RST signal and creates the RESET condition. The INIT maintains SEL signal true and releases the DATA BUS (SCSI IDs). Subsequently, the INIT waits for the response from TARG for at least 200 µs (SELECTION About Time) + 90 ns (Deskew Delay 2). If no response is detected, the INIT releases the SEL signal allowing the SCSI bus to go to the BUS FREE phase. If the INIT detects the response from TARG during this period, the INIT considers the SELECTION phase to have completed normally. 1-36

52 Figure 1.23 SELECTION phase 1-37