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Re: Parallax Propeller

From rickman <gnuarm@gmail.com>
Newsgroups comp.lang.forth, comp.arch.embedded
Subject Re: Parallax Propeller
Date 2013-01-26 18:07 -0500
Organization A noiseless patient Spider
Message-ID <ke1nkh$bb2$3@dont-email.me> (permalink)
References (7 earlier) <qvvjf81u8h341ng3ndmnq48egqhqjf5r9f@4ax.com> <7xwqv9m2ub.fsf@ruckus.brouhaha.com> <9ejmf8hp8uf95n8ot7fqq3tv80tkb2cf7o@4ax.com> <20130124232504.16848.3314@localhost.localdomain> <20130125214801.18426.45870@localhost.localdomain>

Cross-posted to 2 groups.

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On 1/25/2013 4:57 PM, None wrote:
> rickman<gnuarm@gmail.com>  writes:
>> How do you know the display "fuzziness" was due to software timing?  I
>> would expect software timing on a clocked processor to be on par with
>> other means of timing.  There are other aspects of design that could
>> cause fuzziness or timing ambiguities in the signal.
>
> If you look at the inner loop driving the output pin, you can do a min/max
> skew calculation which ends up with quite a bit of jitter on the table.
> The product is the PockeTerm, you can pick one up at:
>
>      http://www.brielcomputers.com/wordpress/?cat=25
>
> It's open source, VGA_HiRes_Text.spin is the low level driver for
> VGA output.  Note it actually uses *two* CPUs, and is some pretty darn
> cool assembly code--written by the president of the Propeller company!
>
> Andy Valencia
> Home page: http://www.vsta.org/andy/
> To contact me: http://www.vsta.org/contact/andy.html

I don't follow what causes the skew you mention.  Instruction timings 
are deterministic, no?  If not, trying to time using code is hopeless. 
If the timings are deterministic, the skew should not be cumulative 
since they are all based on the CPU clock.  Is the CPU clock from an 
accurate oscillator like a crystal?  If it is using an internal RC 
clock, again timing to sufficient accuracy is hopeless.

Rick

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Thread

Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-13 06:37 +0000
  Re: Parallax Propeller MK <mk@nospam.co.uk> - 2013-01-13 10:26 +0000
    Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-13 12:22 +0000
      Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-13 07:24 -0600
        Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-13 13:55 +0000
          Re: Parallax Propeller mhx@iae.nl (Marcel Hendrix) - 2013-01-13 17:13 +0200
            Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-16 06:23 -0600
              Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-16 15:01 +0000
                Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-16 09:12 -0600
                Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-16 15:36 +0000
                Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-16 10:59 -0600
                Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-16 23:38 +0000
                Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-17 04:04 -0600
                Re: Parallax Propeller Mark Wills <forthfreak@gmail.com> - 2013-01-17 04:52 -0800
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-01-24 22:48 -0800
                Re: Parallax Propeller Mark Wills <forthfreak@gmail.com> - 2013-01-24 23:10 -0800
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-01-28 17:42 -0800
                Re: Parallax Propeller "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-05 06:05 -0500
                Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-05 08:41 -0600
                Re: Parallax Propeller Paul Rubin <no.email@nospam.invalid> - 2013-02-05 10:21 -0800
                Re: Parallax Propeller Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-05 21:37 +0100
                Re: Parallax Propeller "Elizabeth D. Rather" <erather@forth.com> - 2013-02-05 10:44 -1000
                Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-05 15:52 -0600
                Re: Parallax Propeller Paul Rubin <no.email@nospam.invalid> - 2013-02-06 00:29 -0800
                Re: Parallax Propeller Paul Rubin <no.email@nospam.invalid> - 2013-02-06 00:31 -0800
                Re: Parallax Propeller Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-06 19:46 +0100
                Re: Parallax Propeller Paul Rubin <no.email@nospam.invalid> - 2013-02-09 00:11 -0800
                Re: Parallax Propeller anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-09 10:25 +0000
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-02-06 18:26 -0800
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-02-05 15:07 -0800
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-02-05 15:49 -0800
                Re: Parallax Propeller "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-05 06:04 -0500
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-02-05 15:21 -0800
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-16 18:09 -0500
          Re: Parallax Propeller Ben Bradley <ben_u_bradley@etcmail.com> - 2013-01-18 21:07 -0500
            Re: Parallax Propeller "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-01-19 10:06 +0000
              Re: Parallax Propeller Arlet Ottens <usenet+5@c-scape.nl> - 2013-01-19 13:04 +0100
              Re: Parallax Propeller "A. K." <akk@nospam.org> - 2013-01-19 13:22 +0100
                Re: Parallax Propeller Bernd Paysan <bernd.paysan@gmx.de> - 2013-01-19 13:38 +0100
              Re: Parallax Propeller David Brown <david.brown@removethis.hesbynett.no> - 2013-01-19 17:12 +0100
                Re: Parallax Propeller albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-01-19 16:45 +0000
                Re: Parallax Propeller David Brown <david.brown@removethis.hesbynett.no> - 2013-01-20 17:49 +0100
                Re: Parallax Propeller upsidedown@downunder.com - 2013-01-19 20:54 +0200
                Re: Parallax Propeller Paul Rubin <no.email@nospam.invalid> - 2013-01-19 11:04 -0800
                Re: Parallax Propeller upsidedown@downunder.com - 2013-01-19 23:05 +0200
                Re: Parallax Propeller Mark Wills <markrobertwills@yahoo.co.uk> - 2013-01-20 01:05 -0800
                Re: Parallax Propeller Arlet Ottens <usenet+5@c-scape.nl> - 2013-01-20 12:11 +0100
                Re: Parallax Propeller upsidedown@downunder.com - 2013-01-20 13:53 +0200
                Re: Parallax Propeller upsidedown@downunder.com - 2013-01-20 13:26 +0200
                Re: Parallax Propeller Les Cargill <lcargill99@comcast.com> - 2013-01-19 14:23 -0600
                Re: Parallax Propeller Les Cargill <lcargill99@comcast.com> - 2013-01-19 14:18 -0600
                Re: Parallax Propeller David Brown <david.brown@removethis.hesbynett.no> - 2013-01-20 20:32 +0100
                Re: Parallax Propeller Les Cargill <lcargill99@comcast.com> - 2013-01-20 18:08 -0600
                Re: Parallax Propeller Walter Banks <walter@bytecraft.com> - 2013-01-20 17:12 -0500
                Re: Parallax Propeller Mel Wilson <mwilson@the-wire.com> - 2013-01-20 19:19 -0500
                Re: Parallax Propeller Walter Banks <walter@bytecraft.com> - 2013-01-20 21:12 -0500
                Re: Parallax Propeller David Brown <david@westcontrol.removethisbit.com> - 2013-01-21 09:01 +0100
                Re: Parallax Propeller Walter Banks <walter@bytecraft.com> - 2013-01-21 21:11 -0500
                Re: Parallax Propeller upsidedown@downunder.com - 2013-01-22 09:39 +0200
                Re: Parallax Propeller Mel Wilson <mwilson@the-wire.com> - 2013-01-22 10:14 -0500
              Re: Parallax Propeller Waldek Hebisch <hebisch@math.uni.wroc.pl> - 2013-01-20 02:03 +0000
            Re: Parallax Propeller George Neuner <gneuner2@comcast.net> - 2013-01-19 12:29 -0500
              Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-23 12:29 -0500
                Re: Parallax Propeller Mark Wills <markrobertwills@yahoo.co.uk> - 2013-01-24 14:03 -0800
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-01-24 22:55 -0800
                Re: Parallax Propeller Mark Wills <forthfreak@gmail.com> - 2013-01-24 23:03 -0800
                Re: Parallax Propeller Coos Haak <chforth@hccnet.nl> - 2013-01-25 20:02 +0100
                Re: Parallax Propeller Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-01-28 17:13 -0800
                Re: Parallax Propeller David Brown <david@westcontrol.removethisbit.com> - 2013-01-29 09:15 +0100
                Re: Parallax Propeller Anders.Montonen@kapsi.spam.stop.fi.invalid - 2013-01-30 12:19 +0000
                Re: Parallax Propeller David Brown <david.brown@removethis.hesbynett.no> - 2013-01-30 21:18 +0100
                Re: Parallax Propeller Mark Wills <forthfreak@gmail.com> - 2013-01-30 22:57 -0800
                Re: Parallax Propeller Alex McDonald <blog@rivadpm.com> - 2013-01-31 10:38 -0800
                Re: Parallax Propeller Mark Wills <forthfreak@gmail.com> - 2013-01-31 12:34 -0800
            Re: Parallax Propeller Paul Rubin <no.email@nospam.invalid> - 2013-01-19 10:42 -0800
              Re: Parallax Propeller bob@bob.com - 2013-01-19 19:56 -0600
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-23 12:40 -0500
                Re: Parallax Propeller None <vandys@vsta.org> - 2013-01-24 23:26 +0000
                Re: Parallax Propeller Walter Banks <walter@bytecraft.com> - 2013-01-25 11:49 -0500
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-25 09:25 -0500
                Re: Parallax Propeller None <vandys@vsta.org> - 2013-01-25 21:57 +0000
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-26 18:07 -0500
                Re: Parallax Propeller Mark Wills <markrobertwills@yahoo.co.uk> - 2013-01-27 00:50 -0800
                Re: Parallax Propeller Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-01-27 03:30 -0600
                Re: Parallax Propeller Dombo <dombo@disposable.invalid> - 2013-01-27 12:58 +0100
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-28 21:38 -0500
                Re: Parallax Propeller None <vandys@vsta.org> - 2013-01-27 03:09 +0000
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-28 21:51 -0500
                Re: Parallax Propeller None <vandys@vsta.org> - 2013-01-30 02:10 +0000
                Re: Parallax Propeller rickman <gnuarm@gmail.com> - 2013-01-30 18:32 -0500
            Re: Parallax Propeller David Schultz <abuse@127.0.0.1> - 2013-01-20 11:21 -0600
      Re: Parallax Propeller albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-01-13 16:24 +0000
      Re: Parallax Propeller David Brown <david@westcontrol.removethisbit.com> - 2013-01-14 10:51 +0100
        Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-16 06:06 +0000
          Re: Parallax Propeller David Brown <david@westcontrol.removethisbit.com> - 2013-01-16 13:43 +0100
            Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-16 15:27 +0000
      Re: Parallax Propeller Rafael Deliano <rafael_deliano@arcor.de> - 2013-01-15 21:10 +0100
        Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-16 06:26 +0000
      Re: Parallax Propeller gavino_himself <visploveslisp@gmail.com> - 2013-01-22 06:26 -0800
    Re: Parallax Propeller Peter Jakacki <peterjakacki@gmail.com> - 2013-01-13 12:44 +0000

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