The speeds are ~30MHz, the length of the bus is hopefully to be less than
12"

The goals are speed, size and cost (high speed, small size, low cost).
However the speed is pretty much set (30MHz) and the cost is the next
biggest concern.
The brands of bus devices used are:
Epson (S1D13506 LCD controller)
Motorola MCF5307 microprocessor
Micron SDRAM
Fujitsu FLASH memory
SMSC Ethernet Controller
Analog Devices AS21065L
none of these have inbuilt termination resistors, or any form of drive
control that I know of (please advise me if I'm wrong on this).

The 32bits is pretty much required to maintain bus throughput.  A serial bus
isn't an option.

I'm leaning towards the AC termination method, as that consumes the lowest
power.  However I'm not too sure whether the rise/fall times would be quick
enough using such a termination method.  Any words of wisdom etc would be
greatly appreciated, I can't seem to get much info from my tutors, it would
seem it's slightly above most of them :(

Thanks guys,
Bevan Weiss


----- Original Message -----
From: "Tony Karavidas" <[EMAIL PROTECTED]>
To: "'Protel EDA Forum'" <[EMAIL PROTECTED]>
Sent: Friday, September 27, 2002 5:28 PM
Subject: Re: [PEDA] OT: termination for a multidrop bidirectional bus


> What sort of speed are you running? What length is this bus. What are
> you goals for the project: speed, size, cost?? Do you need 32 bits?
> Could you incorporate a serial bus? What brand do you intent to use?
> Some have series resistors built in (Phillips). Depending on your
> answers, you could go from no termination to any method you mentioned
> below. Welcome to the world of engineering and design tradeoffs...
>
>
>
> > -----Original Message-----
> > From: Bevan Weiss [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, September 26, 2002 9:53 PM
> > To: Protel EDA Forum
> > Subject: Re: [PEDA] OT: termination for a multidrop bidirectional bus
> >
> >
> > Hi,
> > sorry to ask this question to you guys, but I'm more likely
> > to get an answer from the people dealing with the technology
> > so to speak...
> >
> > What kind of termination is applicable for a multidrop
> > bidirectional bus (using LVTTL signals)??  I've thought about
> > series termination, one for each driver on the bus (however
> > that would total 256 resistors for a 32bit wide bus).  Thus
> > it's not my preferred method.  I also would prefer to avoid
> > parallel termination (or thevenin equilavent or ac
> > termination for that
> > matter) just because they would take up more inter-trace spacing.
> >
> > I'm sure that many of you have had this kind of situation
> > before and have some advice.  It's for a student design
> > project and the deadline is quickly approaching.
> >
> > Thanks,
> > Bevan Weiss
> >
>

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