Re: GA144 Application Board

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.forth
Subject	Re: GA144 Application Board
References	<49556347-7bf6-494b-92be-f7c8aff18880@z31g2000vbt.googlegroups.com> <7xvcm6o9qi.fsf@ruckus.brouhaha.com> <0d702ca7-8af4-4b99-8d12-1320b239d2be@9g2000vbq.googlegroups.com>
Date	2012-03-22 08:52 -0700
Message-ID	<7xk42c3a5w.fsf@ruckus.brouhaha.com> (permalink)
Organization	Nightsong/Fort GNOX

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rickman <gnuarm@gmail.com> writes:
>> 1. Crystal oscillator (controlled by GA node or otherwise)
> I'm very disappointed in the lack of a follow up on the oscillator
> app...  until that happens the oscillator will be a self contained
> unit.  I expect the board to have both a 32.768 kHz oscillator and a
> higher speed one, likely either 24 or 25 or maybe 24.768 MHz.

Sounds good, if the cpu's can keep up with that.  I would have thought
100 khz or 1 mhz to be a good speed, with a software PLL to multiply it
up if necessary.  Dividing it down is easy.
>
> The trouble with isolated I/O is the board space and the wide range of

OK.

>> 3. Control processor (i.e. traditional cheap microcontroller) 
>
> I'm not clear why an MCU would be needed for this rather than using
> the self boot feature of the GA144.  Any processor you add would need
> to be upgradable, by this rational, requiring yet another processor.

Conventional MCU's are easier to program is the main reason.  For
example, you want ethernet on the board.  Are you planning to code a
TCP/IP stack for the GA144?  If not, you want a conventional cpu
available (or an fpga that can run a softcore).  (Hmm, maybe there is a
TCP/IP in eforth that can run on the GA virtual machine).  I don't see
why the conventional cpu would have to be upgradeable, just that it
could run some reasonable code.

> My thinking is to provide an 8 bit wide on-the-go USB PHY.

I have the impression that USB needs a software stack almost as
complicated as TCP/IP, but I don't know much about it either.

>> 5. How about some op amps that could be used as level converters
> What range of levels are you thinking of? 

I've forgotten why I asked about this, but yes, below 5v.
>
>> 7. Provision (pads on board) for high resolution (18 bit) ADC/DAC. 
> The GA144 has unlimited resolution ADC and even DAC.  There is a trade
> off between resolution and sample rate and is one of the things they
> did totally right on the GA144.  I think this chip gives you just less
> than CD quality, about 15 bits at 48 ksps.

I think some audio users will find that insufficient.  If anything they
really want 24/48, but in accurate 18/48 will allow the best reasonable
input for the GA144 to then implement signal processing on the samples.

> There isn't much GPIO really.  If you use the memory interface for
> memory there are only 21 I/Os left.  Makes it hard to interface to a
> lot of things.  

Hmm, I didn't realize that the memory interface ate all the pins like
that.  Maybe the memory bus can be narrower than 16 bits.

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Thread

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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