RE: scale signal integrity pictures & a new question
Rick Sparber
Recall that the line driver in the scale is designed to be powered by a
watch battery. Not a lot of drive power available.
I do have a small high freq cap plus a dipped tant on that scale and those
signals are quiet. One interesting thing is that my Z axis cable is far
shorter than my X and Y cables plus the Y slider is from the same store as
the Z (Harbor Freight). Now, I know that HF changes suppliers all of the
time but the two boards look identical.
I have not played with ARMs so I refer you to Bruce.
Rick
-----Original Message-----
From: Druid Noibn [mailto:druid...@yahoo.com]
Sent: Monday, November 02, 2009 6:25 PM
To: 'Bruce Fairman'; 'Lester Caine'; Rick Sparber
Cc: 'Lawrence W. Gill '
Subject: Re: scale signal integrity pictures & a new question
Hi Rick,
Nice sceen shots - it's nice what computers do for us.
I am a little suprised by the waveforms so the first thing I ask myself is
what would a known good waveform look like? Here "good" means fast rise and
fall times.
Assuming the waveforms are recorder accurately, I wonder if adding a few
caps to the chip(s) power connections would be advantageous - I am partial
to small ceramics with small tants.
Whether this has anything to do with any of the problems - I have no idea.
NEW QUESTION
The last time I worked on programming embedded microprocessors it was the
Intel 8755. The DRO550 uses an ARM7 and the thought was to pick up one of
the development boards (kits) that I saw on eBay - I a also on the TI
distribution list for their products and many look like a lot of fun to
experiment with.
In any event,any suggestions as to a kit that might be used for working with
the ARM7? I might have an application or two and it seems that it might be
worth using.
Comments please.
Take care,
John
--- On Sun, 11/1/09, Rick Sparber <rgsp...@aol.com> wrote:
> From: Rick Sparber <rgsp...@aol.com>
> Subject: scale signal integrity pictures
> To: "'Bruce Fairman'" <b...@phlogiston.com>, "'Lester Caine'"
<les...@lsces.co.uk>, "'Druid Noibn'" <druid...@yahoo.com>
> Cc: "'Lawrence W. Gill '" <rep...@roadrunner.com>
> Date: Sunday, November 1, 2009, 7:15 PM
> Here is some data I collected today.
> The take home message is that before
> and after the comparators all scale signals looked good. I
> see nothing
> special about the Z axis signals yet it is the Z axis that
> causes the
> spurious beep every few minutes. I just realized I forgot
> to move scales
> around to prove that the problem moves with the scale.
>
> Anyway, what do you think of these traces? I took them with
> my new digital
> scope that feeds my laptop.
>
> Rick
>