Re: GA144 Application Board

Newsgroups	comp.lang.forth
From	Albert van der Horst <albert@spenarnc.xs4all.nl>
Subject	Re: GA144 Application Board
Date	2012-03-22 11:36 +0000
Message-ID	<m1aaxl.5zw@spenarnc.xs4all.nl> (permalink)
Organization	Dutch Forth Workshop
References	<49556347-7bf6-494b-92be-f7c8aff18880@z31g2000vbt.googlegroups.com> <0d702ca7-8af4-4b99-8d12-1320b239d2be@9g2000vbq.googlegroups.com> <m18khv.6fd@spenarnc.xs4all.nl> <5eb4fce2-726b-4dfe-b699-8c1c592294b6@hv2g2000vbb.googlegroups.com>

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In article <5eb4fce2-726b-4dfe-b699-8c1c592294b6@hv2g2000vbb.googlegroups.com>,
rickman  <gnuarm@gmail.com> wrote:
>> >> 6. External SRAM for the GA144, similar to GA's own eval board
>>
>> >With the limited internal ram, yes, external RAM is required. =A0I find
>> >it interesting that with the internal word size being 18 bits, the GA
>> >eval board and SRAM board have 16 bit memory. =A0I looked for 18 bit
>> >memory, but it seems to be very expensive now. =A0At one time it was
>> >quite common and not so expensive.
>>
>> With 18 bits you should interface a 16 bit CAS 16 bit RAS memory.
>
>I have no idea what a 16 bit CAS 16 bit RAS memory is.  Are you
>talking about SDRAM, DDR or DDR2?  What are the 16 bits?

All the dynamic ram chips, since the 4016 16K times 1 , use
a multiplexing for the row and column addressing, so 16K amounts
to 7 Row Addres Strobe lines and & 7 Column Address Strobe lines
on the same pins.
Virtually all EDO ...DDR3 has this mechanisme.

>
>
>> Using this kind of cheap memory 4 Gbyte would not be much slower
>> than the bit-banging that is done now.
>
>Slower???  In app note 3, fast static ram runs at 5 MHz cycle times.
>I think even 133 MHz SDRAM can run about 5 times faster than this
>while doing single word accesses.  I might use an SDRAM rather than an
>SRAM.  I'll need to look at a few issues though.

With the need to multiplex the CAS and RAS strobes by hand from the
GA144 speed might suffer a bit.
But we are in  the unique situation
that we dedicate a whole processor to the memory interface.
This approach saves half of the address lines and money.
The lines are used better.

>
>
>> So I want a 32 bit eForth
>> with 4 Gbyte addressable memory before I would even consider
>> using an ISO Forth on the GA144. This could use cheap discarded
>> memory from PC's, by the way.
>
>Isn't 4 GB a bit much?  PDA's, tablets and cell phones don't have that
>much memory!  Geeze, this PC I am typing on only has 4 GB!!!  The idea
>of scrounging PC's at the dump for memory is a bit funny.  I think a
>$4 SRAM or SDRAM chip will do the job ok.

PDA's tables and cell phones have not the data processing capability
of a GA144. So the GA144 needs more data to process.
When the 16G and 256 Gb arrive, we should use that,
17 and 18 bits CAS/RAS strobes. At 18 bits 256G there may be a
natural limit for the GA144 though.

<SNIP>

>
>Rick

Groetjes Albert

--
-- 
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

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GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-10 17:24 -0800
  Re: GA144 Application Board Rafael Deliano <Rafael_Deliano@arcor.de> - 2012-03-11 10:10 +0100
    Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-11 04:33 -0700
      Re: GA144 Application Board emmanuel <emmanuel.said@cern.ch> - 2012-03-11 06:00 -0700
        Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-11 19:41 -0700
      Re: GA144 Application Board Rafael Deliano <Rafael_Deliano@arcor.de> - 2012-03-11 16:03 +0100
        Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-11 13:45 -0700
  Re: GA144 Application Board Jecel <jecel@merlintec.com> - 2012-03-11 12:33 -0700
  Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-11 19:45 +0000
    Re: GA144 Application Board Matthias Koch <koch@pci.uni-hannover.de> - 2012-03-15 14:11 +0100
  Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-14 19:53 -0700
    Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-20 20:15 -0700
      Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-21 13:08 +0000
        Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-21 12:13 -0700
          Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-22 11:36 +0000
            Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-22 17:50 +0000
              Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-22 14:50 -0700
                Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-23 12:24 +0000
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-23 10:11 -0700
                Re: GA144 Application Board Roger Ivie <rivie@ridgenet.net> - 2012-03-23 13:15 -0500
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-24 11:51 -0700
                Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-25 12:06 +0000
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-25 12:50 -0700
                GA144 memory interfacing was Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-26 13:00 +0000
                Re: GA144 memory interfacing was Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-26 20:03 -0700
                Re: GA144 memory interfacing was Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-28 12:21 +0000
                Re: GA144 memory interfacing was Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-28 07:59 -0700
            Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-22 14:26 -0700
          Re: GA144 Application Board hwfwguy@gmail.com - 2012-03-22 12:25 -0700
            Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-22 13:07 -0700
              Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-22 14:54 -0700
                Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-22 15:00 -0700
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-23 10:15 -0700
                Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-23 17:32 -0700
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-24 12:01 -0700
                Re: GA144 Application Board Jan Coombs <jan_2011-02@murray-microft.co.uk> - 2012-03-24 22:27 +0000
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-24 19:13 -0700
                Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-24 16:01 -0700
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-24 19:18 -0700
                Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-25 13:06 -0700
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-25 15:02 -0700
                Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-25 15:51 -0700
                Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-25 16:38 -0700
            Re: GA144 Application Board Richard Owlett <rowlett@pcnetinc.com> - 2012-03-22 16:54 -0500
              Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-23 10:17 -0700
            Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-22 14:52 -0700
            Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-23 12:34 +0000
              Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-23 10:24 -0700
            Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-23 14:22 +0000
      Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-22 08:12 -0700
        Re: GA144 Application Board Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-23 12:38 +0000
      Re: GA144 Application Board Paul Rubin <no.email@nospam.invalid> - 2012-03-22 08:52 -0700
        Re: GA144 Application Board rickman <gnuarm@gmail.com> - 2012-03-22 15:00 -0700
  Time to revisit S100 Bus? - was [Re: GA144 Application Board] Richard Owlett <rowlett@pcnetinc.com> - 2012-03-22 20:17 -0500
    Re: Time to revisit S100 Bus? - was [Re: GA144 Application Board] rickman <gnuarm@gmail.com> - 2012-03-23 10:29 -0700

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