Date: Dec 28, 1989 X3T9.2/89-150R1 To: X3T9.2 Committee (SCSI) From: George Penokie (IBM) Subject: 16 Bit Data Path on a Single 68 pin Connector This is the appendix form of the 16 Bit Data Path on a single 68 pin connector. In an attempt to follow the recommended principles for appendixes (in other words the KISS principle) I have limited the appendix to only include the following: -A short description of the physical interconnect methods. -References to the B cable for all cable, connector, and term power specifications. -Pin outs for the P and Q cables single ended and differential connectors. -No reference to additional SCSI ID addresses. If this is appendix is adopted I would recommend a separated CCS type document be published which incorporates proposal X3T9.2/89- 094Rx. Appendix K - Alternate Connectors for 16/32 Bit Data Path K.1. Physical Description 16/32 bit cabling alternatives: SCSI devices are daisy-chained together using a common 68-conductor P cable and, optionally, a 68-conductor Q cable. Both ends of all cables are terminated. All signals are common between all SCSI devices on the P cable. In systems that employ the Q cable wide SCSI option, wide SCSI devices additionally connect to the Q cable. Various width SCSI devices may be mixed. Physical devices with P cable connectors shall connect the low data byte (DB0-DB7,P) to the P connector. The high data byte (DB8-DB15,P1) may be connected to the P connector. The A/B cable and P/Q cable alternatives are mutually exclusive within a system. Physical devices with A cable connectors may be attached to P cables. Physical devices with B cable connectors shall not be attached to P or P/Q cables. Physical devices with P and P/Q cable connectors shall not be attached to A or A/B cables. K.2. Cabling The P and Q cables shall follow the same specifications for cables and connectors as described for the B cable in Section 4 of this standard. K.3. Terminator Power The P and Q cables shall follow the same specifications for terminator power as described for the B cable in Section 4 of this standard. K.4. P/Q Cable Contact Assignments Table K-1: Single-Ended Contact Assignments - P cable ============================================================================== Connector Cable Connector Signal Contact Conductor Contact Signal Name Number Number Number Name ------------------------------------------------------------------------------ GROUND 1 1 | 2 35 -DB(12) GROUND 2 3 | 4 36 -DB(13) GROUND 3 5 | 6 37 -DB(14) GROUND 4 7 | 8 38 -DB(15) GROUND 5 9 | 10 39 -DB(P1) GROUND 6 11 | 12 40 -DB(0) GROUND 7 13 | 14 41 -DB(1) GROUND 8 15 | 16 42 -DB(2) GROUND 9 17 | 18 43 -DB(3) GROUND 10 19 | 20 44 -DB(4) GROUND 11 21 | 22 45 -DB(5) GROUND 12 23 | 24 46 -DB(6) GROUND 13 25 | 26 47 -DB(7) GROUND 14 27 | 28 48 -DB(P) GROUND 15 29 | 30 49 GROUND GROUND 16 31 | 32 50 GROUND TERMPWR 17 33 | 34 51 TERMPWR TERMPWR 18 35 | 36 52 TERMPWR RESERVED 19 37 | 38 53 RESERVED GROUND 20 39 | 40 54 GROUND GROUND 21 41 | 42 55 -ATN GROUND 22 43 | 44 56 GROUND GROUND 23 45 | 46 57 -BSY GROUND 24 47 | 48 58 -ACK GROUND 25 49 | 50 59 -RST GROUND 26 51 | 52 60 -MSG GROUND 27 53 | 54 61 -SEL GROUND 28 55 | 56 62 -C/D GROUND 29 57 | 58 63 -REQ GROUND 30 59 | 60 64 -I/O GROUND 31 61 | 62 65 -DB(8) GROUND 32 63 | 64 66 -DB(9) GROUND 33 65 | 66 67 -DB(10) GROUND 34 67 | 68 68 -DB(11) ============================================================================== NOTES: (1) The minus sign next to a signal indicates active low. (2) The conductor number refers to the conductor position when using 0.025-inch centerline flat ribbon cable. Other cable types may be used to implement equivalent contact assignments. (3) 8 bit devices which connect to the P-cable shall leave the following signals open: -DB(12) -DB(13) -DB(14) -DB(15) -DB(P1) -DB(8) -DB(9) -DB(10) -DB(11) All other signals shall be connected as defined. Table K-2: Single-Ended Contact Assignments - Q cable |============================================================================== | Connector Cable Connector | Signal Contact Conductor Contact Signal | Name Number Number Number Name |------------------------------------------------------------------------------ | GROUND 1 1 | 2 35 -DB(28) | GROUND 2 3 | 4 36 -DB(29) | GROUND 3 5 | 6 37 -DB(30) | GROUND 4 7 | 8 38 -DB(31) | GROUND 5 9 | 10 39 -DB(P3) | GROUND 6 11 | 12 40 -DB(16) | GROUND 7 13 | 14 41 -DB(17) | GROUND 8 15 | 16 42 -DB(18) | GROUND 9 17 | 18 43 -DB(19) | GROUND 10 19 | 20 44 -DB(20) | GROUND 11 21 | 22 45 -DB(21) | GROUND 12 23 | 24 46 -DB(22) | GROUND 13 25 | 26 47 -DB(23) | GROUND 14 27 | 28 48 -DB(P2) | GROUND 15 29 | 30 49 GROUND | GROUND 16 31 | 32 50 GROUND | TERMPWRB 17 33 | 34 51 TERMPWRB | TERMPWRB 18 35 | 36 52 TERMPWRB | RESERVED 19 37 | 38 53 RESERVED | GROUND 20 39 | 40 54 GROUND | GROUND 21 41 | 42 55 TERMINATED | GROUND 22 43 | 44 56 GROUND | GROUND 23 45 | 46 57 TERMINATED | GROUND 24 47 | 48 58 TERMINATED | GROUND 25 49 | 50 59 TERMINATED | GROUND 26 51 | 52 60 TERMINATED | GROUND 27 53 | 54 61 TERMINATED | GROUND 28 55 | 56 62 TERMINATED | GROUND 29 57 | 58 63 TERMINATED | GROUND 30 59 | 60 64 TERMINATED | GROUND 31 61 | 62 65 -DB(24) | GROUND 32 63 | 64 66 -DB(25) | GROUND 33 65 | 66 67 -DB(26) | GROUND 34 67 | 68 68 -DB(27) |============================================================================== NOTES: (1) The minus sign next to a signal indicates active low. (2) The conductor number refers to the conductor position when using 0.025- inch centerline flat ribbon cable. Other cable types may be used to implement equivalent contact assignments. Table K-3: Differential Contact Assignments - P cable ============================================================================== Connector Cable Connector Signal Contact Conductor Contact Signal Name Number Number Number Name ------------------------------------------------------------------------------ +DB(12) 1 1 | 2 35 -DB(12) +DB(13) 2 3 | 4 36 -DB(13) +DB(14) 3 5 | 6 37 -DB(14) +DB(15) 4 7 | 8 38 -DB(15) +DB(P1) 5 9 | 10 39 -DB(P1) GROUND 6 11 | 12 40 GROUND +DB(0) 7 13 | 14 41 -DB(0) +DB(1) 8 15 | 16 42 -DB(1) +DB(2) 9 17 | 18 43 -DB(2) +DB(3) 10 19 | 20 44 -DB(3) +DB(4) 11 21 | 22 45 -DB(4) +DB(5) 12 23 | 24 46 -DB(5) +DB(6) 13 25 | 26 47 -DB(6) +DB(7) 14 27 | 28 48 -DB(7) +DB(P) 15 29 | 30 49 -DB(P) DIFFSENS 16 31 | 32 50 GROUND TERMPWR 17 33 | 34 51 TERMPWR TERMPWR 18 35 | 36 52 TERMPWR RESERVED 19 37 | 38 53 RESERVED +ATN 20 39 | 40 54 -ATN GROUND 21 41 | 42 55 GROUND +BSY 22 43 | 44 56 -BSY +ACK 23 45 | 46 57 -ACK +RST 24 47 | 48 58 -RST +MSG 25 49 | 50 59 -MSG +SEL 26 51 | 52 60 -SEL +C/D 27 53 | 54 61 -C/D +REQ 28 55 | 56 62 -REQ +I/O 29 57 | 58 63 -I/O GROUND 30 59 | 60 64 GROUND +DB(8) 31 61 | 62 65 -DB(8) +DB(9) 32 63 | 64 66 -DB(9) +DB(10) 33 65 | 66 67 -DB(10) +DB(11) 34 67 | 68 68 -DB(11) ============================================================================== NOTES: (1) The conductor number refers to the conductor position when using 0.025- inch centerline flat ribbon cable. Other cable types may be used to implement equivalent contact assignments. (2) 8 bit devices which connect to the P-cable shall leave the following signals open: -DB(12) -DB(13) -DB(14) -DB(15) -DB(P1) -DB(8) -DB(9) -DB(10) -DB(11) +DB(12) +DB(13) +DB(14) +DB(15) +DB(P1) +DB(8) +DB(9) +DB(10) +DB(11) All other signals shall be connected as defined. Table K-4: Differential Contact Assignments - Q cable ============================================================================== Connector Cable Connector Signal Contact Conductor Contact Signal Name Number Number Number Name ------------------------------------------------------------------------------ +DB(28) 1 1 | 2 35 -DB(28) +DB(29) 2 3 | 4 36 -DB(29) +DB(30) 3 5 | 6 37 -DB(30) +DB(31) 4 7 | 8 38 -DB(31) +DB(P3) 5 9 | 10 39 -DB(P3) GROUND 6 11 | 12 40 GROUND +DB(16) 7 13 | 14 41 -DB(16) +DB(17) 8 15 | 16 42 -DB(17) +DB(18) 9 17 | 18 43 -DB(18) +DB(19) 10 19 | 20 44 -DB(19) +DB(20) 11 21 | 22 45 -DB(20) +DB(21) 12 23 | 24 46 -DB(21) +DB(22) 13 25 | 26 47 -DB(22) +DB(23) 14 27 | 28 48 -DB(23) +DB(P2) 15 29 | 30 49 -DB(P2) DIFFSENS 16 31 | 32 50 GROUND TERMPWRB 17 33 | 34 51 TERMPWRB TERMPWRB 18 35 | 36 52 TERMPWRB RESERVED 19 37 | 38 53 RESERVED TERMINATED 20 39 | 40 54 TERMINATED GROUND 21 41 | 42 55 GROUND TERMINATED 22 43 | 44 56 TERMINATED TERMINATED 23 45 | 46 57 TERMINATED TERMINATED 24 47 | 48 58 TERMINATED TERMINATED 25 49 | 50 59 TERMINATED TERMINATED 26 51 | 52 60 TERMINATED TERMINATED 27 53 | 54 61 TERMINATED TERMINATED 28 55 | 56 62 TERMINATED TERMINATED 29 57 | 58 63 TERMINATED GROUND 30 59 | 60 64 GROUND +DB(24) 31 61 | 62 65 -DB(24) +DB(25) 32 63 | 64 66 -DB(25) +DB(26) 33 65 | 66 67 -DB(26) +DB(27) 34 67 | 68 68 -DB(27) ============================================================================== NOTES: (1) The minus sign next to a signal indicates active low. (2) The conductor number refers to the conductor position when using 0.025- inch centerline flat ribbon cable. Other cable types may be used to implement equivalent contact assignments.