Question about the difference between A3000-16/50 and A3000-25/50
Wayne G Rigby
>I am considering upgrading from an A1000 to an A3000. I would like to stay
>cheap and get an A3000-16/50 through the "Power Up" program. I intend to
>add an '040 board, when they are available, but I am concerned about the
>bus speed. Is the 68040 co-processor slot synchronized with the motherboard
>clock? I realize that the CHIP RAM operates at a 14.xx Mhz to be NTSC
>compatible and that the processor is asynchronous with respect to it, but
>what about a co-processor? I know that the co-processor on the A2000 is
>synchronized when accessing motherboard/Zorro II RAM but it has local 32 bit
>memory.
>
>In short: if I buy a 3000-16/50, will any future '040 run at a higher speed?
>If I intend to run a 25 Mhz '040, will I need an A3000-25/50? I am aware of
>RAM speeds and can select any FAST RAM to be of the appropriate speed for
>either 16 or 25 Mhz.
>
If you got an '040 board, the board would basically take over the bus and
run at its own clock speed. So if you got, for example, a 70 MHz 68070
accelerator board, your computer would run at 70 MHz, and your 16 MHz
68030/68881 or 25 MHz 68030/68882 would be disabled for all intents and
purposes. Of course, if you had a coprocessor board that ran at the same
speed as your on board CPU, it would be possible to use both of the processors
(the '040 & '030/882). This, of course, will not be seen for a while, since
the present OS doesn't support dual processors; but as some future development,
it might be seen.
>Thanks,
>-ethan
>
>
>
>
>--
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Wayne Rigby
Computer and Systems Engineer (in training)
Rensselaer Polytechnic Institute
meta...@rpi.edu
Ethan R Dicks
cheap and get an A3000-16/50 through the "Power Up" program. I intend to
add an '040 board, when they are available, but I am concerned about the
bus speed. Is the 68040 co-processor slot synchronized with the motherboard
clock? I realize that the CHIP RAM operates at a 14.xx Mhz to be NTSC
compatible and that the processor is asynchronous with respect to it, but
what about a co-processor? I know that the co-processor on the A2000 is
synchronized when accessing motherboard/Zorro II RAM but it has local 32 bit
memory.
In short: if I buy a 3000-16/50, will any future '040 run at a higher speed?
If I intend to run a 25 Mhz '040, will I need an A3000-25/50? I am aware of
RAM speeds and can select any FAST RAM to be of the appropriate speed for
either 16 or 25 Mhz.
Thanks,
Dave Haynie
>In article <116...@tut.cis.ohio-state.edu> e...@giza.cis.ohio-state.edu (Ethan R Dicks) writes:
>>In short: if I buy a 3000-16/50, will any future '040 run at a higher speed?
>>If I intend to run a 25 Mhz '040, will I need an A3000-25/50? I am aware of
>>RAM speeds and can select any FAST RAM to be of the appropriate speed for
>>either 16 or 25 Mhz.
>If you got an '040 board, the board would basically take over the bus and
>run at its own clock speed. So if you got, for example, a 70 MHz 68070
>accelerator board, your computer would run at 70 MHz, and your 16 MHz
>68030/68881 or 25 MHz 68030/68882 would be disabled for all intents and
>purposes.
Not quite. The A3000 motherboard can be run at either 16MHz or 25MHz. Period.
Some come with a 16MHz 68030 and 68881, which wouldn't work at 25MHz. So the
motherboard gets a 16MHz clock, thus keeping the 68030/68881 happy. Just like
in the A2000, a coprocessor card can have any processor running at any speed
it likes. However, when that card talks to the A3000 motherboard, it must look
like a 16MHz 68030 if the A3000 is set for 16MHz, a 25MHz 68030 if the A3000
is set for 25MHz. Since it was obvious early on that some coprocessor boards
might NEED, depending on design, to run synchronously to the A3000 motherboard,
and thus supply their own clock, we made it possible for a designer to let this
happen. So it's possible for a coprocessor board (68040, whatever) to run the
A3000 motherboard at 25MHz, even if it came stuffed for 16MHz operation.
However, in such a cranked up system, the original 16MHz 680x0 chips will have
to stay shut down.
--
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
{uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy
"That's me in the corner, that's me in the spotlight" -R.E.M.
Neil Richmond
.Not quite. The A3000 motherboard can be run at either 16MHz or 25MHz. Period.
.Some come with a 16MHz 68030 and 68881, which wouldn't work at 25MHz. So the
.motherboard gets a 16MHz clock, thus keeping the 68030/68881 happy. Just like
.in the A2000, a coprocessor card can have any processor running at any speed
.it likes. However, when that card talks to the A3000 motherboard, it must look
.like a 16MHz 68030 if the A3000 is set for 16MHz, a 25MHz 68030 if the A3000
.is set for 25MHz. Since it was obvious early on that some coprocessor boards
.might NEED, depending on design, to run synchronously to the A3000 motherboard,
.and thus supply their own clock, we made it possible for a designer to let this
.happen. So it's possible for a coprocessor board (68040, whatever) to run the
.A3000 motherboard at 25MHz, even if it came stuffed for 16MHz operation.
.However, in such a cranked up system, the original 16MHz 680x0 chips will have
.to stay shut down.
Dave,
Is this a jumpered option or is it software selectable? I am guessing that this
is going to be a jumper somewhere on the A3000 motherboard. What you are saying
in effect is that the 16 mhz version of the A3000 will never run as a co-
processor with the 60040 board, but will have to be replaced by the 68040 board,
right?
neil
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GUY GARNETT
A friend of mine just purchased an A3000-16/50 under the PowerUP
program. He was wondering what (if it is even possible) he needs to
do, if at some point in the future he wants to upgrade it to 25Mhz
operation.
Obviously, he would need to replace the 68030, 68882, and clock
crystal with 25Mhz parts (he is guessing that these parts will become
much cheaper in the next couple of years, making such an upgrade
financially feasable). Is there anything else which needs to be done
(jumpers moved, other parts upgraded?). Are all of these things
socketed?
Wildstar
(who wishes *HE* had $1800 to upgrade his A1000 to a A3000-16/50)