Accredited Standards Committee X3, Information Processing Systems Doc. No.: X3T9.2/92-203 R0 Date: November 7, 1992 Project: 855-D Ref. Doc.: X3T9.2/91-010 Reply to: D.W. Spence To: Membership of X3T9.2 From: Lawrence J. Lamers, Secretary X3T9.2 D.W. Bill Spence Chair X3T9.2/SPI Working Group Subject: Minutes of SPI October 14, '92 Working Group Meeting ______________________________________________________________________________ Agenda 1. Opening Remarks 2. Attendance and Membership 3. Approval of Agenda 4. Review of SPI Revision 7 (Spence) 5. Single-ended Input Current (Stai) 6. Test Circuit for Pin Capacitance (Spence) 7. Temperature Effect on External Transceivers (Shergill) 8. 24ma Current Limit (Allgood) 9. Cable Impedance Spec (Allgood) 10. IN & OUT Icon (Allgood) 11. Meeting Schedule 12. Adjournment Results of Meeting 1. Opening Remarks Bill Spence, the Chair, called the meeting to order at 9:00 a.m., Wednesday October 14, 1992. He thanked Buzz Rigsbee of Boeing Computer Services for hosting the meeting. As is customary, the people attending introduced themselves. A copy of the attendance list was circulated for attendance and corrections. It was stated that the meeting had been authorized by X3T9.2 and would be conducted under the X3 rules. Ad hoc meetings take no final actions, but prepare recommendations for approval by the X3T9.2 task group. The voting rules for the meeting are those of the parent committee, X3T9.2. These rules are: one vote per company; and any participating company member may vote. The minutes of this meeting will be posted to the SCSI BBS and the SCSI Reflector and will be included in the next committee mailing. 2. Attendance and Membership Attendance at working group meetings does not count toward minimum attendance requirements for X3T9.2 membership. Working group meetings are open to any person or company to attend and to express their opinion on the subjects being discussed. The following people attended the meeting: Name Status Organization Phone Number ------------------------- ------ ------------------------------ -------------- Mr. Norm Harris P Adaptec, Inc. (408) 945-8600 x2230 Mr. Shahnad Nadershahi P Amdahl Corp. (408) 944-3767 Mr. Jeff Rosa P Amphenol Interconnect (607) 786-4222 Mr. Christian Mollard O BULL Systems (33)130807128 Mr. Clifford E. Strang P BusLogic (408) 492-9090 Jr. Mr. Joe Chen P Cirrus Logic Inc. (510) 226-2101 Mr. Michael Smith S Dallas Semiconductor (214) 450-0457 Mr. Tom Hunt V Dallas Semiconductor (415) 617-1790 Mr. Greg McSorley A Data General Corp. (508) 870-8829 Dr. William Ham A Digital Equipment Corp. (508) 841-2629 Mr. Skip Jones P Emulex Corp. (714) 668-5058 Mr. D. W. Spence A ENDL Associates (512) 255-0339 Mr. Robert Liu P Fujitsu Computer Products,Am (408) 894-3790 Mr. Steve Caron P Furukawa Electric America (404) 487-1234 Mr. George Penokie P IBM Corp. (507) 253-5208 Ms. Gricell Co S IBM Corp. (512) 838-3664 Mr. Larry Grasso S IBM Corp. (512) 838-3672 Mr. Robert D. Allgood A Iomega Corp. (801) 778-3709 Mr. David H. Shaff P JAE (305) 563-3484 Mr. Paul Butkevich V Judd Wire, Inc. (413) 863-4357 Mr. Edward Myscich V KBS, Inc. (305) 360-7200 Mr. Ben Khoshnood V KBS, Inc. (305) 360-7200 Mr. Lawrence J. Lamers P Maxtor Corp. (408) 432-3889 Mr. Jim McGrath A Molex Inc. (708) 969-4550 Mr. Robbie Shergill P National Semiconductor (408) 721-7959 Mr. John Lohmeyer P NCR Corp. (719) 596-5795 x362 Mr. Harvey Waltersdorf P Thomas & Betts (803) 676-2905 Mr. Alan Ebright P Toshiba America, Inc. (408) 428-4831 Mr. Mark Jordan S Unitrode Integrated Circuits (603) 429-8628 29 People Present Status Key: P - Principal Member A - Alternate Member L - Liaison Member O - Observer S,V - Visitor 3. Approval of Agenda The proposed agenda was approved. 4. Review of SPI Revision 7 (Spence) Bill Spence marched through the SPI document page by page requesting any comments or corrections. All of the input was taken and edited into revision 8 on-line. Revision 8 will be available for the November SPI meeting. John Lohmeyer mentioned that as a result of the document review at Toronto during September clause 10 needed substantial editing. Clause 10 needs to be re-cast into services and indications so that it interfaces properly with the upper layer protocol (SIP). 5. Single-ended Input Current (Stai) Jeff Stai stated that he had reports that the +/- 20 microamp specification for single-ended input current was difficult to meet in the power-off state. He did not have any further information to quantify the problem, but did request that other silicon folks examine the issue. This item will be on the agenda for the November SPI meeting. 6. Test Circuit for Pin Capacitance (Spence) Dean Wallace and Bill Spence proposed developing an annex to specify a test circuit for measurement of pin capacitance. The value of measure capacitance can vary a great deal with different measurement techniques and power states. It is intended to include a proposed measurement technique in revision 8 and review it at the November SPI meeting. 7. Temperature Effect on External Transceivers (Shergill) Robbie Shergill was into a consciousness raising effort regarding the effect of temperature on differential skew for external transceivers. The transmitter and receiver skew delays have been removed from section 9 and placed in Annex C along with a note developed in the working group warning folks of the temperature effects. 8. 24ma Current Limit (Allgood) The current limit specified in section 7.1.1 item b) was again a subject of discussion. This issue has been discussed a number of times during the development of SPI. It always ends up the silicon folks against the system folks. The system folks want a higher limit on current to use clamped terminators which are needed in some configurations to assure correct operation. The silicon folks are adamantly against changing the limit, claiming that their parts would need to be re-characterized and/or re-designed and there would be negative effects on the MTBF and expected life of the product. The Forced Perfect Terminators work with the existing silicon, it is just that they are not within the legal limits in SPI. (And they may or may not adversely affect the life of the drivers.) This time around the discussion went on a different tack in that what was requested was a 10-15% increase in current but retaining the "..shall not exceed..". The silicon folks agreed to go off and examine this approach. 9. Cable Impedance Spec (Allgood) In Table 1 of SPI the characteristic cable impedance is specified with a maximum and minimum value. Robert Allgood suggested that a nominal value with a tolerance was a more useful specification for the typical user. The working group agreed to change the impedance to 84 +/- 12 ohms for single- ended cables and to 122 +38/-7 ohms for differential cables. 10. IN & OUT Icon (Allgood) Robert Allgood proposed an addition to the SCSI icon to indicate an in or out direction for the cable. The reason this is needed is that the enclosures have a built-in terminator so the daisy-chain needs to be assembled in a directional fashion. (The terminator is closer to the out connector.) There was little support for modification of the existing icon, partly due to the effort involved and partly due to the fact that this is not a universal problem. 11. Meeting Schedule The next meeting of the SPI Working Group will be November 11, 1992 from 2:00 pm to 8:00 pm at the Sheraton Hotel (408-745-6000) in Sunnyvale, CA hosted by Amdahl Corporation. The room rates are $100.00 plus tax. The reservation deadline for these rates is October 16, 1992. 12. Adjournment The meeting was adjourned at 6:00 p.m. on Wednesday October 14, 1992.