jwwalden@miavx1.acs.muohio.edu (Darc Tangent) (03/05/91)
Would there be a noticeable speed difference between an A3000/16 with a 68040 accelerator and an A3000/25 with the same accelerator? I know that the new custom chips in the A3000 are clocked at the same rate as the main processor so there should be some difference, but I was wondering if anyone had a good idea of how much difference there would be and what operations in particular the difference would affect. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Darc Tangent "She's a brain trapped in the body of a jwwalden@miavx1.acs.muohio.edu game show hostess" - _Say_Anything_
holgerl@amiux.UUCP (Holger Lubitz) (03/06/91)
In article <4101.27d2e586@miavx1.acs.muohio.edu> jwwalden@miavx1.acs.muohio.edu (Darc Tangent) writes: >I know that the new >custom chips in the A3000 are clocked at the same rate as the main processor This is the first time I read about custom chips running at a higher rate than 14.32 MHz (and even slightly slower in PAL Amigas) Processor Clock Rate on the chip bus ? You are not talking about a chip bus running at 25 MHz bus speed, are you ? Could some hardware guru out there (hello dave !?) confirm this if it is true ? Or is it simply some kind of misunderstanding on my part ? Eagerly waiting for an answer, Holger -- Holger Lubitz | holgerl@amiux.uucp Kl. Drakenburger Str. 24 | holgerl@amiux.han.de D-W-3070 Nienburg | cbmvax.commodore.com!cbmehq!cbmger!amiux!holgerl
krauss@mansw1.enet.dec.com (Michael Krauss) (03/06/91)
In article <holgerl.0243@amiux.UUCP>, holgerl@amiux.UUCP (Holger Lubitz) writes: > >In article <4101.27d2e586@miavx1.acs.muohio.edu> jwwalden@miavx1.acs.muohio.edu (Darc Tangent) writes: > >>I know that the new >>custom chips in the A3000 are clocked at the same rate as the main processor > >This is the first time I read about custom chips running at a higher rate >than 14.32 MHz (and even slightly slower in PAL Amigas) >Processor Clock Rate on the chip bus ? You are not talking about a >chip bus running at 25 MHz bus speed, are you ? > [...] I don't no at which rate the custom chips are running, but as far as I remember there is a jumper on the motherboard of the A3000 that changes some timings of the customchips.(It has two settings: one for 16M and one for 25M.) > >-- >Holger Lubitz | holgerl@amiux.uucp >Kl. Drakenburger Str. 24 | holgerl@amiux.han.de >D-W-3070 Nienburg | cbmvax.commodore.com!cbmehq!cbmger!amiux!holgerl > -- ============================================================================== Michael Krauss #include <std_disclaimer.h> DEC Mannheim, Germany "AMIGA or VAX, nothing else please !" "krauss@mansw1.enet.dec.com" or "...!decwrl!mansw1.enet!krauss"
milamber@caen.engin.umich.edu (Daryl Scott Cantrell) (03/06/91)
In article <1991Mar6.142824.12241@hollie.rdg.dec.com> decwrl!mansw1.enet!krauss writes: >> >>In article <4101.27d2e586@miavx1.acs.muohio.edu> jwwalden@miavx1.acs.muohio.edu (Darc Tangent) writes: >> >>>I know that the new >>>custom chips in the A3000 are clocked at the same rate as the main processor >> >>This is the first time I read about custom chips running at a higher rate >>than 14.32 MHz (and even slightly slower in PAL Amigas) >>Processor Clock Rate on the chip bus ? You are not talking about a >>chip bus running at 25 MHz bus speed, are you ? >> [...] > >I don't no at which rate the custom chips are running, but as far as I remember >there is a jumper on the motherboard of the A3000 that changes some timings of >the customchips.(It has two settings: one for 16M and one for 25M.) > As far as I know, the custom chips in all Amigas run at 7.14 MHz (for now, hopefully). The 16/25 MHz clock in an A3000 drives a totally different bus. I think you might be thinking of the two pairs of shorting posts in the 3000 that configure ROMs based on the type of chip and the speed of the bus. I think these are for determining wait states and such.. As to the original question, the only differences between a 3000/25 and a 3000/16 are: oscillator 68030 rating FPU type/rating In other words, the entire 030 bus of a 3000/16 is built to go 25 MHz, but doesn't (unless you were to plop something into the 200-pin CPU slot).. So when you get that 040 accelorator, it will go 25 MHz in either. >>Holger Lubitz | holgerl@amiux.uucp >Michael Krauss #include <std_disclaimer.h> >"krauss@mansw1.enet.dec.com" or "...!decwrl!mansw1.enet!krauss" -- +---------------------------------------+----------------------------+ | // Daryl S. Cantrell | These opinions are | | |\\\ milamber@caen.engin.umich.edu | shared by all of // | | |// Evolution's over. We won. | Humanity. \X/ | +---------------------------------------+----------------------------+
jwwalden@miavx1.acs.muohio.edu (Darc Tangent) (03/07/91)
Thank you for your answer to my question. What I meant by new custom chips (which seems to have confused everyone) was the RAMSey and other new chips that are specific to the A3000. Sorry for the confusion about that. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Darc Tangent "Giants are just like people, only bigger. jwwalden@miavx1.acs.muohio.edu Much, much bigger!" jwwalden@miavx1.bitnet - the witch in _Into_the_Woods_
daveh@cbmvax.commodore.com (Dave Haynie) (03/09/91)
In article <holgerl.0243@amiux.UUCP> holgerl@amiux.UUCP (Holger Lubitz) writes: >In article <4101.27d2e586@miavx1.acs.muohio.edu> jwwalden@miavx1.acs.muohio.edu (Darc Tangent) writes: >>I know that the new >>custom chips in the A3000 are clocked at the same rate as the main processor >This is the first time I read about custom chips running at a higher rate >than 14.32 MHz (and even slightly slower in PAL Amigas) OK. The original "Amiga" chips in the A3000, Agnus, Denise, and Paula, work from a two phase clock, nominally 7MHz -- 7.16MHz for NTSC, 7.09MHz for PAL. Since the two clocks, called C7M and CDAC, are 90 degrees apart, the chips are effectively clock at 14MHz, and the basic chip memory cycle is equivalent to a 14MHz 68000 cycle. The new A3000 system chips, Buster, DMAC, Gary, and Ramsey, are clocked by the CPU clock (16MHz or 25MHz). At least Buster and Ramsey are actually clock by this clock, called CPUCLK, and another 25MHz clock delayed by 90 degrees, called CLK90. Buster actually uses both edges of both clocks at various points in the logic. There are a few reasons for using a two phase clock rather than a single clock running at double speed. First of all, the 68030 runs from the 25MHz clock, so it's much easier to feed that same clock to the custom chips that need it than it is to build a 50MHz clock that's exactly synchronized to that 25MHz clock. Secondly, real fast clocks are harder to keep clean on the PCB, and noisier when it comes time for FCC testing. Finally, the gate array technology used for these parts is much happier with a couple 25MHz clocks on input than a 50MHz clock. From the point of view of the actual circuit design, you really don't care. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett