Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!bbn!oberon!uscacsc!papa From: papa@uscacsc.UUCP (Marco Papa) Newsgroups: comp.sys.amiga Subject: Re: What's in a name (and who is "Fang")? (long) Message-ID: <277@uscacsc.UUCP> Date: Mon, 21-Sep-87 01:10:31 EDT Article-I.D.: uscacsc.277 Posted: Mon Sep 21 01:10:31 1987 Date-Received: Tue, 22-Sep-87 01:22:15 EDT References: <14218@amdahl.amdahl.com> <2336@cbmvax.UUCP> <14580@amdahl.amdahl.com> Reply-To: papa@pollux.UUCP (Marco Papa) Organization: Felsina Software, Los Angeles Lines: 99 Keywords: jumpers for 1 Meg of CHIP ram The following are excerpts from the "Commodore Amiga A500/A2000 Techical Reference Manual", a 240-page manual that also includes ALL schematics of the A500, A2000 (the German design) and the B2000 (the WestChester design). All the references pertain to differences betwenn the various Amiga computers (now 4: A1000, A500, A2000, B2000). My comments are within [..]. "Video Output: ... An A500 genlock will also have to supply its own power [which means that one CAN'T use the A1000 genlock even with an extension cable]". "On the A500, memory at $C00000 is "slow" RAM rather than fast RAM as suggested by A1000 external expansion" "A500, A2000, and B2000 support the RS232 RI [Ring Indicator] lead to allow operation with modem standards". "The light pen input on the A500 and B2000 has been moved to the second mouse port. ... On the B2000 the light pen can be jumpered to port 0" "The A500 and B2000 provide a full-bandwidth 16-level grey-scale composite video output." "The A500 and B2000 can cut out the anti-aliasing filterby programmatically turning off the power on LED". [An entire chapter is dedicated to the "Coprocessor Expansion and 86 pin Signals". The important changes concern the differences between the A2000 and the B2000 implementation. There are lots of differences in the pin descriptions, but the key phrases are the following ones:] "In the A2000, the coprocessor Slot signals that control DMA can be used to insert the coprocessor in the place of the normal 68000... This isn't a totally transparent replacement. ... The B2000 solves these problems with a higher-level DMA protocol. " "The A2000 doesn't support autoconfiguration from the Coprocessor point-of view, the B2000 does. .... Its impossible to normally autoconfigure any device in the coprocessor slot of the A2000. The coprocessor slot is configured first on the B2000." "[on the B2000] the Coprocessor can be a real Coprocessor, functioning as the equivalent of the 68000 as far as the whole Amiga system is concerned." [Now about the Amiga Video Slot:] "The B2000 adds a second 36-pin connector that supplies additional audiovideo information." [The first Video slot provides Analog Video plus 4 bits of digital video among other things] "These in conjunction with other signals found on the second video connector provide access to the full 12 bits of digital video output produced by the Denise chip". [The B2000 video slots also provides a composite video signal, light pen input, all 8-bits of the paraller port (bidirectional)]. "It can be used to control various aspects of a complex video interface". [ Left and right audio channels and filter cutoff are also on this slot.] [Now with the B2000 jumpers:] [One] jumper determines the high-order address bit for Fat Agnus (Fang). In its normal position, the high order bit is A23; in its other position, this bit is A19. The current Fat Agnus chip requires the A23 signal for proper management of the memory at $C00000 [hint, hint!]. Future Fat Agnus chips may map things differently." [Other jumpers are provided for setting light pen port, time-base for CIA timer, location of second floppy drive, and enable/disable memory at $C00000]. I hope that this clears up some of the questions. Now some notes. The Manual is VERY well done. A must for hardware and device driver writers for the A/B2000 There are sections on the Amiga expansion (100pin, 86pin and video slot) and all the docs for the bridgeboard (how to access the PC/XT/AT emulator and Janus Library calls). A whole chapter on the Amiga Hard Disk/SCSI Controller, and also detailed descriptions (part from the old Amiga Hardware manual) on the Fat Agnus chip are aso included. Diagrams (including form factors) of all the amigas are in an appendix, and ALL the schematics are provided. The manual is available for $40 from Lauren Brown of CATS at the usual address. If you are into low-level things, this manual is a must. The manual is copyright (C) 1986, 1987 by Commodore-Amiga, Inc. Now since one (1) person complained about the length of my signature, I have decided to shorten it to 2 lines. BUT, as Leo was allowed one last showing, I'll run my old signature for one more time :). The new one is at the end. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Marco Papa 3175 S. Hoover St., Ste. 275 (213)669-1497 Los Angeles, CA 90007 (213)743-3752 F E L S I N A Now working for ::::::: BIX: papa But in no way :: :: Officially representing ::::::: ...!oberon!pollux!papa S O F T W A R E papa@cse.usc.edu -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- --Marco (Felsina Software) From sheet 1of12 of the B2000 Schematics: "Something in the way she moves.."