Article 22047 of comp.sys.sun.hardware: Xref: mri-gw alt.sys.sun:12201 comp.sys.sun.hardware:22047 comp.sys.sun.misc:17021 Path: mri-gw!psinntp!psinntp!psinntp!gatech!howland.reston.ans.net!xlink.net!xlink100!ka.sub.net!rz.uni-karlsruhe.de!stepsun.uni-kl.de!serv-200.dfki.uni-kl.de!dfki.uni-kl.de!koch From: koch@dfki.uni-kl.de (Peter Koch) Newsgroups: alt.sys.sun,comp.sys.sun.hardware,comp.sys.sun.misc Subject: Re: Sun VME backplane questions Date: 13 Jun 1995 09:53:08 +0200 Organization: DFKI, University of Kaiserslautern, Germany Lines: 94 Distribution: inet Message-ID: References: <3rg3rd$3vq@orb.apana.org.au> NNTP-Posting-Host: serv-400.dfki.uni-kl.de Hi! cdewick@orb.apana.org.au (Craig Dewick) writes: >Anyway, in articles I read in these groups, people talk about the correct >position to insert various cards. Is there a guide to where cards should >be inserted, and if so, how can I obtain it? I'm aware that the CPU board >is supposed to sit in slow #1, and the SCSI board goes into slot #7 I >believe, but what about other cards? The RAM board is fitted in slot #3 at >the moment. Sun's Field Engeneers Handbook contains lots of tables for the board placement. But they aren't really helpfull, if you want to know, why a card has to be placed in some slot. If you know the "why", you're more flexible in making a working configuration, even if Sun doesn't mention it ;-) Remember, we're talking about the backplane used in the 3/160, 3/180, 3/260, 3/280, 3/460, 3/480, 4/260, 4/280, 4/360 and 4/380. Other backplanes have a different layout. Here are the facts: The VME-Bus gives higer priority to cards in slots with lower numbers. This is the reason, why the CPU should be placed in slot 1. Slot 7 is special, because it wires the SCSI-Bus through the backplane to a connector on the other side. If you have an old Sun-2 SCSI board without external DB-50 connector, it has to be placed in slot 7. A flat ribbon cable runs from the connector on the other side of the backplane to the SCSI devices. Slots 1-6 have a common memory bus. Therfore, all memory boards have to be placed in slots 1-6. A Floating Point Accellerator uses this memory bus too. The memory bus needs to be terminated. Therfore, the leftmost (usually the CPU) and the rightmost card need termination resistors. The CPU usually has already termination resistors installed and the memory cards do have an empty socket for the termination resistors. Slot 10-12 have a common memory bus too. Slot 7,8,9 are not connected and slot 7 uses the absence of the memory bus to wire through the SCSI- Bus to the other side. >Also, what about the jumpers on the 'front' of the backplane? For each >slot except the last there are five jumper locations set up in a group of >four 2-pin block and one seperate 2-pin block sitting a little lower by >itself? What do these jumpers do, and how are they meant to be configured? 0 1 2 3 4 5 6 7 8 9 10 11 12 BG0 : : : : : : : : : : : : : BG1 : : : : : : : : : : : : : BG2 : : : : : : : : : : : : : BG3 : : : : : : : : : : : : : IACK : : : : : : : : : : : : n/a These jumpers are connected to the daisy-chain input/output pins of the VME-Bus. If they are installed, the daisy-chain is "wired though". The jumpers PXX0-PXX3 (XX stands for the slot number) are bus grant 0-3 and PXX4 is the interrupt acknowledge daisy-chain. All jumpers have to be installed for empty slots. If you don't set the jumpers, if you remove a card, all cards in slots with higher numbers aren't recognized. Sun uses only bus grant 3 and interrupt acknowledge. card BG3 IACK -------------------------------------------------------- CPU out out all disk/tape controllers out out ethernet, FDDI controllers out out GP graphics processor out out memory boards in in FPA in in ALM-1 out (see FEH) ALM-2, MCP in out color,CG5,CG9 in out Some third party cards use BG0-2 too (example: Symbolics Lisp machines). Look into their documentation for correct installation of the cards. >On a related topic, is it possible to convert the machine into a Sun-4 >simply by replacing the Motorola CPU board with a Sparc CPU board (once I >obtain suitable boot tapes, etc......)? I'm considering this as an option >in the future as the price of surplus Sparc boards fall. No problem. If you find a 4/200 or 4/300 CPU, you can simply plug it in. But the 3/400 CPU is very zippy indeed! Bye Peter -- ------------------------------------------------------------------- Peter Koch, Universitaet Kaiserslautern (DFKI-ISG, Raum 57/282) Erwin-Schroedinger-Strasse, 67663 Kaiserslautern (Germany) Tel: 0631/205-3455, E-mail: koch@dfki.uni-kl.de