kim@amdahl.amdahl.com (Kim DeVaughn) (09/19/87)
In article <2336@cbmvax.UUCP>, higgin@cbmvax.UUCP (Paul Higginbottom SALES) writes: > In article <14218@amdahl.amdahl.com> I wrote: > $I just received the July/August issue of Amiga Mail from CBM today... > $there were some > $references made to "B2000 Jumpers", "A2000/B2000 Keyboard Connector", and > $"Schematics (A2000, B2000, A500)". > $ > $OK, I'll byte ... what's a B2000? > > The original Amiga 2000 designed in Germany and sold everywhere EXCEPT the > U.S since the Spring was internally designated as the "A2000". In the U.S, > it was only shipped to developers, and to some sales reps for demonstration > purposes. > > The B2000 is the U.S designed and assembled Amiga 2000. There are only > small differences as far as most users are concerned. The main difference > is that the B2000 has 1Mb RAM on the motherboard, and the A2000 has 512K > on the motherboard, and 512K on a card which is pre-installed into the CPU > expansion slot. So, the West Chester design is officially known as the B2000. Aside from the memory difference you noted above, my understanding is that the video slot of the B2000 makes available the 12 raw RGB signals. Is that correct? And as to the jumpers mentioned in AmigaMail ... I recently heard the following *rumor* from a "reliable source": "The West Chester 2000 (B2000) has a jumper that will enable 1M of chip memory. There will be a new Agnes chip called Fang." Sounds like this will a field upgrade option in the future. Comments? /kim -- UUCP: kim@amdahl.amdahl.com or: {sun,decwrl,hplabs,pyramid,ihnp4,uunet,oliveb,cbosgd,ames}!amdahl!kim DDD: 408-746-8462 USPS: Amdahl Corp. M/S 249, 1250 E. Arques Av, Sunnyvale, CA 94086 CIS: 76535,25
papa@uscacsc.UUCP (Marco Papa) (09/21/87)
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.."bryce@hoser.berkeley.edu.UUCP (09/24/87)
In article <277@uscacsc.UUCP> papa@pollux.UUCP (Marco Papa) writes: >The following are excerpts from the "Commodore Amiga A500/A2000 Techical >Reference Manual": >[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." [One] on the A500 this is JP3. To move the RAM you also need to disable the _exram signal into Gary. This is pulled low if there is ram at $C00000, but needs to float high if you move it to $080000. The input connects pin 32 of the memory connector, or you can lift out Gary and bend Gary pin 32 out. (Neat! same pin on the Gary and memory connector) The memory goes to $080000 and configures as 1 megabyte of chip ram. You can't actually use the machine like this; it will crash as soon as any memory is allocated as chip from the area above $07ffff. Those peope who added the internal 512K memory hacks that showed up at $080000 have the same problem under Kickstart V1.2. They run a program that claims to reoder things to work. The versions I have seen don't. When memory is tight the last few memory allocations get screwed and things crash. (I don't have one of these myself) If you have one of those internal half-fast ram hacks, the solution is to add David Haynie's "AUTOMEG" modification. This brings that memory back into the autoconfiguration scheme. |\ /| . Ack! (NAK, ENQ, SYN) {o O} . (") bryce@hoser.berkeley.EDU -or- ucbvax!hoser!bryce U How can you go back if you have not yet gone forth?
grr@cbmvax.UUCP (George Robbins) (09/29/87)
In article <14580@amdahl.amdahl.com> kim@amdahl.amdahl.com (Kim DeVaughn) writes: > > So, the West Chester design is officially known as the B2000. Aside from the > memory difference you noted above, my understanding is that the video slot > of the B2000 makes available the 12 raw RGB signals. Is that correct? Nope, it's officially an A2000, the B2000 is just an internal designation to confuse the issue. The video slot does have all 12 bits of RGB and some other signals useful for audio/video games, including the parallel port lines in case you want some simple control functions for dedicated applications. > And as to the jumpers mentioned in AmigaMail ... I recently heard the > following *rumor* from a "reliable source": > > "The West Chester 2000 (B2000) has a jumper that will enable 1M of chip > memory. There will be a new Agnes chip called Fang." > > Sounds like this will a field upgrade option in the future. Comments? Well, there might be some jumpers... 8-) But the Fang thing is just some confusion - a contraction for the Fat Agnus chip as used in the A500. When I did some of the early A500 schematics I tried this name on, but it didn't really stick. The WC A2000 schematics were derived from these A500 schematics and I guess the name kind of got carried over. I guess maybe it wasn't such a bad name after all - White Fang! -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
grr@cbmvax.UUCP (George Robbins) (09/29/87)
In article <277@uscacsc.UUCP> papa@pollux.UUCP (Marco Papa) writes: > 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 [..]. > > "The A500 and B2000 provide a full-bandwidth 16-level grey-scale composite > video output." ^^ This was an editorial screw up. The composite monochrome output reflects the normal 4096 colors, however the 60/30/10 RGB->Monochrome weighting reults in some of the shades of grey being a little hard to distinguish, resulting in a number of less than 4096 but considerably more than 16. On the other hand just about any arbitrary color screen makes sense in monochrome, which isn't always the case if you don't do the color weighting. -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)