Re: Cutting panels

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	sci.electronics.design, comp.arch.embedded
Subject	Re: Cutting panels
Date	2013-07-27 00:53 -0700
Organization	Nightsong/Fort GNOX
Message-ID	<7xwqoc7814.fsf@ruckus.brouhaha.com> (permalink)
References	(12 earlier) <ksufhc$4o7$1@speranza.aioe.org> <7x7ggdp2ef.fsf@ruckus.brouhaha.com> <ksun0e$p5a$1@speranza.aioe.org> <7x8v0su5yr.fsf@ruckus.brouhaha.com> <ksvn0l$tj0$1@speranza.aioe.org>

Cross-posted to 2 groups.

Show all headers | View raw

Don Y <this@isnotme.com> writes:
> CAN is essentially a party line "RS232" implementation.  I.e.,
> OK if you want to pass infrequent commands and data

Yeah, its advantage is supposed to be low cost and good robustness
against noise and signal degradation.  The way it gets that appears to
be relatively low speed.  It apparently goes up to 1 megabit (for cable
runs up to 40 meters) but the base speed is 10-20 kbit (good for km
runs).

> E.g., if I query the database for a list of the hundreds of
> emitters feeding the various plants in the yard, a CAN bus
> implementation would be "busy" for many seconds.  

I don't see why you'd have to send the result of such a big query over
the CAN bus.  The idea is to wire the outdoor network with CAN, where
sensors would respond to occasional queries or post updates.  Indoors
(for queries etc.) you'd use wifi or ethernet.

> Consumer devices (which probably represent *90%* of the CPU's sold)
> are very cost sensitive.  If you can do something with 100 bytes of
> RAM instead of 10KB, you'll find only 100 bytes in that product!

I don't think that's meaningful to what most programmers spend their
time doing.  McDonalds might sell 90% of the world's hamburgers, all
cooked with the same recipe written by one guy, but most of the world's
working cooks have done a hamburger recipe at one time or another, using
methods much different than McDonalds.  Similarly, those tiny embedded
cpus (while they ship a lot of them) are programmed by comparatively few
people.  The total amount of code running on them is relatively small.

There are also folks here saying that those 100 byte cpus are being
displaced by 32-bitters with at least a few kilobytes.  I see that
Cortex M0 parts start at 50 cents or so.  Not much room left for
packaged 8-bit processors below that.  The 100 byte cpu may go the way
of the 7400 quad nand gate: it will disappear from circuit boards,
possibly living on in the guts of ASICs.  Programming them becomes the
province of hardware designers.  Again, a specialized niche.

Actually the most common processors may well be GSM SIM cards which have
multiple kilobytes (there are billions of them and they are mostly
programmed in Java for security).

Thread

Cutting panels Don Y <this@isnotme.com> - 2013-07-21 02:47 -0700
  Re: Cutting panels John Fields <jfields@austininstruments.com> - 2013-07-21 08:05 -0500
    Re: Cutting panels Roberto Waltman <usenet@rwaltman.com> - 2013-07-21 10:38 -0400
      Re: Cutting panels "Carl Ijames" <carl.ijames@nonono.verizon.net> - 2013-07-21 12:36 -0400
        Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 09:48 -0700
          Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 13:29 -0700
            Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 14:10 -0700
              Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 16:23 -0700
          Re: Cutting panels Grant Edwards <invalid@invalid.invalid> - 2013-07-21 21:04 +0000
            Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 15:07 -0700
              Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 16:35 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 17:11 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 16:27 -0700
                Re: Cutting panels Robert Wessel <robertwessel2@yahoo.com> - 2013-07-23 21:50 -0500
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 21:24 -0700
                Re: Cutting panels Jasen Betts <jasen@xnet.co.nz> - 2013-07-24 09:09 +0000
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-24 16:02 -0700
          Re: Cutting panels hamilton <hamilton@nothere.com> - 2013-07-21 16:52 -0600
            Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 17:13 -0700
        Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 12:35 -0700
  Re: Cutting panels amdx <nojunk@knology.net> - 2013-07-21 09:54 -0500
    Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 09:32 -0700
      Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 13:36 -0700
        Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-21 14:04 -0700
    Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-21 13:14 -0700
      Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-21 13:26 -0700
        Re: Cutting panels [solved?] Joerg <invalid@invalid.invalid> - 2013-07-21 14:06 -0700
          Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-21 16:08 -0700
            Re: Cutting panels [solved?] Rich Webb <webb.ra@example.net> - 2013-07-21 19:42 -0400
              Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-23 21:45 -0700
            Re: Cutting panels [solved?] Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2013-07-22 07:51 +0000
            Re: Cutting panels [solved?] Charlie E. <edmondson@ieee.org> - 2013-07-23 05:57 -0700
              Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-23 14:46 -0700
                Re: Cutting panels [solved?] Don Lancaster <don@tinaja.com> - 2013-07-23 16:41 -0700
                Re: Cutting panels [solved?] Charlie E. <edmondson@ieee.org> - 2013-07-23 17:21 -0700
                Re: Cutting panels [solved?] Jasen Betts <jasen@xnet.co.nz> - 2013-07-24 09:26 +0000
                Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-25 12:11 -0700
                Re: Cutting panels [solved?] Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2013-07-25 16:04 -0400
                Re: Cutting panels [solved?] Don Y <this@isnotme.com> - 2013-07-25 13:03 -0700
          Re: Cutting panels [solved?] Jasen Betts <jasen@xnet.co.nz> - 2013-07-23 13:40 +0000
            Re: Cutting panels [solved?] Joerg <invalid@invalid.invalid> - 2013-07-23 07:38 -0700
      Re: Cutting panels [solved?]/summary Don Y <this@isnotme.com> - 2013-07-29 15:18 -0700
  Re: Cutting panels andrews@sdf.lonestar.org - 2013-07-21 12:45 -0700
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-22 19:17 -0700
  Re: Cutting panels Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2013-07-21 19:45 -0400
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 17:07 -0700
  Re: Cutting panels Peter Bennett <peterbb@somewhere.invalid> - 2013-07-21 16:57 -0700
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 20:58 -0700
      Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-21 21:02 -0700
      Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-22 09:20 -0700
        Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-22 12:15 -0700
          Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-22 16:17 -0700
            Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-22 18:52 -0700
              Re: Cutting panels Jasen Betts <jasen@xnet.co.nz> - 2013-07-23 14:00 +0000
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 15:13 -0700
              Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-23 07:09 -0700
                Re: Cutting panels Charlie E. <edmondson@ieee.org> - 2013-07-23 10:03 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 21:59 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 15:54 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-24 13:09 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-24 15:51 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-26 09:13 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-26 11:35 -0700
                Re: Cutting panels Paul Rubin <no.email@nospam.invalid> - 2013-07-26 12:06 -0700
                Re: Cutting panels Jan Panteltje <panteltje@yahoo.com> - 2013-07-26 19:44 +0000
                Re: Cutting panels Paul Rubin <no.email@nospam.invalid> - 2013-07-26 22:21 -0700
                Re: Cutting panels Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2013-07-27 08:12 +0000
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-26 13:42 -0700
                Re: Cutting panels Paul Rubin <no.email@nospam.invalid> - 2013-07-26 18:50 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-26 22:49 -0700
                Re: Cutting panels Paul Rubin <no.email@nospam.invalid> - 2013-07-27 00:53 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-27 10:16 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-26 23:52 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-27 17:36 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-28 09:22 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-28 12:31 -0700
                Re: Cutting panels Paul Rubin <no.email@nospam.invalid> - 2013-07-28 13:48 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-28 14:20 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-28 16:35 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-28 17:39 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-28 19:38 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-29 11:15 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-29 16:30 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-29 17:38 -0700
                Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-29 21:45 -0700
                Re: Cutting panels Joerg <invalid@invalid.invalid> - 2013-07-30 12:20 -0700
  Re: Cutting panels Jeff Liebermann <jeffl@cruzio.com> - 2013-07-21 21:38 -0700
  Re: Cutting panels Robert Wessel <robertwessel2@yahoo.com> - 2013-07-22 00:39 -0500
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-22 01:39 -0700
      Re: Cutting panels Robert Wessel <robertwessel2@yahoo.com> - 2013-07-22 19:09 -0500
        Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-22 20:10 -0700
          Re: Cutting panels Jasen Betts <jasen@xnet.co.nz> - 2013-07-23 14:07 +0000
  Re: Cutting panels Theo Markettos <theom+news@chiark.greenend.org.uk> - 2013-07-22 18:33 +0100
    Re: Cutting panels Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2013-07-22 13:44 -0400
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-22 19:00 -0700
      Re: Cutting panels Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2013-07-23 10:09 +0000
      Re: Cutting panels Theo Markettos <theom+news@chiark.greenend.org.uk> - 2013-07-23 11:45 +0100
        Re: Cutting panels Theo Markettos <theom+news@chiark.greenend.org.uk> - 2013-07-23 13:46 +0100
          Re: Cutting panels 0bama <0B@nocontrast.org> - 2013-07-23 13:06 +0000
            Re: Cutting panels Theo Markettos <theom+news@chiark.greenend.org.uk> - 2013-07-23 22:19 +0100
              Re: Cutting panels 0bama <0B@nocontrast.org> - 2013-07-24 08:05 +0000
        Re: Cutting panels Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2013-07-23 10:07 -0400
          Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-25 01:26 -0700
    Re: Cutting panels Jasen Betts <jasen@xnet.co.nz> - 2013-07-23 14:18 +0000
      Re: Cutting panels Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2013-07-23 11:38 -0400
        Re: Cutting panels Theo Markettos <theom+news@chiark.greenend.org.uk> - 2013-07-23 22:32 +0100
          Re: Cutting panels Frank Miles <fpm@u.washington.edu> - 2013-07-23 21:37 +0000
      Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 16:16 -0700
        Re: Cutting panels Theo Markettos <theom+news@chiark.greenend.org.uk> - 2013-07-24 10:37 +0100
          Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-25 01:27 -0700
  Re: Cutting panels Gonadicus <gonadicus@no_spam.com> - 2013-07-23 12:46 +0800
  Re: Cutting panels sms <scharf.steven@geemail.com> - 2013-07-23 04:58 -0700
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 16:13 -0700
  Re: Cutting panels Jasen Betts <jasen@xnet.co.nz> - 2013-07-23 13:25 +0000
    Re: Cutting panels Don Y <this@isnotme.com> - 2013-07-23 21:42 -0700

csiph-web