Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!ncar!hao.hao.ucar.edu!hull From: hull@hao.hao.ucar.edu (Howard Hull) Newsgroups: comp.sys.amiga.hardware Subject: Re: Hard Drives (yet again) Summary: It should work, even if it doesn't. Keywords: A1000 A500 ZorroI ZorroII information Message-ID: <9462@ncar.ucar.edu> Date: 8 Dec 90 20:10:38 GMT References: <3931@corpane.UUCP> <3933@corpane.UUCP> <9279@ncar.ucar.edu> Sender: news@ncar.ucar.edu Distribution: usa Organization: High Altitude Observatory/NCAR, Boulder CO Lines: 104 In article <3933@corpane.UUCP> sparks@corpane.UUCP (John Sparks) writes: >sparks@corpane.UUCP (John Sparks) writes: >... >Also, could someone tell me the bus differences between the A500 and A1000? >I know they are turned around 180 degrees, what I want to know is which pins >are in different locations or have different voltages (I remember someone >mentioning that one pin is 5V on one machine and 12V on the other?). That was probably me, when I was trying to discuss use of an A B -> C switch on the parallel, serial, and video ports and I didn't really want to say much about the expansion ports then (see ncar reference cited in the header above). What I said was: "It IS true that in going from the A1000 to the A500/A2000 one of the pins on the expansion bus (internal to the A2000 only, external with the A500) is -12V while it was -5V on the A1000. But this is not the case for the DB23 video connector." The only inaccuracy I've discovered with what I said is with respect to the A2000's internal 100 pin ZorroII card slot sockets, the pin in question is -5V like it was on the A1000 rather than -12v as it is on the A500 external expansion plug. So yes, Pin 8 of the A1000 is -5V and pin 8 of the A500 is -12V. However, bear in mind that this is a restricted use pin; Commodore advised those manufacturing hardware for the Amiga that they should not use power from that pin in their designs, BUT that if they were manufacturing expansion bay hardware, they should independently supply power to the pin if cost considerations weren't prohibitive. This advisory was on a page of the A1000 "Schematics and Expansion Specification, June 9, 1986" with the header "Apr 24 21:00 1986 memo.expan Page 1" PRELIMINARY and has no doubt evolved some since then. At the time it was issued, it thus implied that such manufacturers should supply -5V on that pin. Those manufacturers who used the pin, and are expecting -12V there will have hardware in the field that may fail when moved to an A1000 or to an adapter cable/box plugged into an A2000. The A2000 has an 86-pin connector (a socket) designed for coprocessor use; the pinout is much the same as the A1000 expansion pinout, but some signals are buffered versions of the 100-pin Zorro II card slots. CBM warns that the differences, while affecting only a few lines, can be different in ways critical for those devices which utilize those few signals... In addition, for your information, the 86 pin and 100 contact connectors do have the same pinout with the exception of pin 8, and with the exception that there are additional signals on the A2000 and it is a socket rather than a card-edge finger extension, which would be considered to be termed a "plug." The additional contacts are listed below: Pin Used as Pin Used as 87 a grounded bus line 88 a grounded bus line 89 a grounded bus line 90 a grounded bus line 91 a grounded bus line 92 7MHz 93 DOE (1K pullup to +5V) 94 _BUSRST (1K pullup to +5V) 95 _GBG (1K gnd via 1000pf) 96 _EINT1 97 a bus line (no name) 98 a bus line (no name) 99 a grounded bus line 100 a grounded bus line Again, you must have knowledge concerning subtle timing and buffering differences between ZorroI and ZorroII, and you must take into consideration the fact that ZorroII slots are intended for autoconfiguring cards. Oh, and yes I should define a few of the above tags: BUSRST - guess what, bus reset; GBG is Generic Bus Grant (related to but not the same as GB) DOE is Data Output Enable, and EINT1 is Encoded Interrupt Line 1 (there are as well some other encoded interrupt lines available for the priority encoder to present to the processor, which then sees it more directly along with all the non-encoded interrupt lines). >I figure if there is only one or two pins swapped or whatever, I can call >back to GVP and Supra and ask them if those pins are used on their drive >controllers. Yes, do give them a call! >Or maybe I can just go into my amiga and do a little wire >swapping/trace cutting to make sure of the compatibility. Yeeeeek. When you're done, you're no longer compatible with whatever you started with. Don't ever forget it and then sell your machine... :-| >Also, how are the pins numbered on the 500 vs. the 1000? Like this? : >(I know they are two rows, on the diagram below I am asking is pin 1 >on the rear side of the 500 and the toward the front on the A1000?) [Diagram omitted] Yes, as you showed it. Odd numbered pins are on the top and even numbered pins are on the bottom (in either case), and pin 1 is to the left when you look at it straight on. The A500 plug is higher above the table, though, so you may have to put an A1000 interface on top of a stack of Walt Disney Mickey Mouse comic books (thus securing a valuable investment) to get it connected in a supported fashion, and, of course, all of the A1000 add-on's front panel lights will a face wall that's behind the A500 (so put your desk in front of a full-length mirror...). Disclaimers: I do have an A1000. I do not own or have access to an A500. I neither work for nor am I in any way associated with CBM. The agency I do work for has a hard enough time figuring out what I do, never matter who ought to be responsible for it. >sparks@corpane.UUCP |PH: (502) 968-DISK 24Hrs/2400BPS | Usenet, Chatting, >=-=-=-=-=-=-=-=-=-=-|7 line Multi-User system. | Downloads & more. >A door is what a dog is perpetually on the wrong side of----Ogden Nash An old Nash is what a Corvette is always trapped behind - Mr. Rambler Howard Hull hull@ncar.ucar.edu