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Groups > comp.arch.embedded > #14006
| From | Rob Gaddi <rgaddi@technologyhighland.invalid> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Sensor wiring |
| Date | 2013-09-30 11:40 -0700 |
| Organization | Highland Technology, Inc. |
| Message-ID | <20130930114040.3542b84b@rg.highlandtechnology.com> (permalink) |
| References | <l2cbm8$qft$1@dont-email.me> <yOmdndkV57j-KtTPnZ2dnUVZ5oOdnZ2d@giganews.com> <l2cfnh$la6$1@dont-email.me> |
On Mon, 30 Sep 2013 14:25:52 -0400 Mel Wilson <mwilson@the-wire.com> wrote: > Tim Wescott wrote: > > > On Mon, 30 Sep 2013 13:16:55 -0400, Mel Wilson wrote: > > > >> I want an I2C connection between a Raspberry Pi and an ATtiny85 over 35m > >> of buried wire. Any guidelines for signal conditioning and protection? > >> Acknowledging that out-of-spec bits per second is a definite possiblity. > > > > [ ...] > > > > I suspect that your best bet would be a simple asynchronous link sending > > serial commands via properly-terminated RS-422. You'll need two twisted > > pairs (one for transmit, one for receive), but it should be dead reliable. > > I was hoping to avoid a crystal on the sensor end and reuse the pins. > Switching to an ATtiny?4 wouldn't kill me, I guess. > > Mel. > If you were desperate to avoid a crystal on the sensor end, you could also run the async RX line to a counter pin, and use the bit timing to servo the on-board oscillator. "I know I'm off by no more than 10%, and I saw a high for 1.95 bits. Therefore it was really high for 2 bits, and I'm running slow by 2.5%" sort of a thing. Though that may wind up being a lot of code-slinging to save a cheap rock/ceramic slab. -- Rob Gaddi, Highland Technology -- www.highlandtechnology.com Email address domain is currently out of order. See above to fix.
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Sensor wiring Mel Wilson <mwilson@the-wire.com> - 2013-09-30 13:16 -0400
Re: Sensor wiring Tim Wescott <tim@seemywebsite.really> - 2013-09-30 12:39 -0500
Re: Sensor wiring Jim Stewart <jstewart@jkmicro.com> - 2013-09-30 11:05 -0700
Re: Sensor wiring Mel Wilson <mwilson@the-wire.com> - 2013-09-30 14:25 -0400
Re: Sensor wiring Rob Gaddi <rgaddi@technologyhighland.invalid> - 2013-09-30 11:40 -0700
Re: Sensor wiring Tim Wescott <tim@seemywebsite.really> - 2013-09-30 14:17 -0500
Re: Sensor wiring Johann Klammer <klammerj@NOSPAM.a1.net> - 2013-09-30 22:30 +0200
Re: Sensor wiring Les Cargill <lcargill99@comcast.com> - 2013-09-30 21:55 -0500
Re: Sensor wiring Don Y <this@isnotme.com> - 2013-09-30 11:58 -0700
Re: Sensor wiring stephenXXX@mpeforth.com (Stephen Pelc) - 2013-09-30 20:05 +0000
Re: Sensor wiring hamilton <hamilton@nothere.com> - 2013-09-30 15:22 -0600
Re: Sensor wiring hamilton <hamilton@nothere.com> - 2013-09-30 15:23 -0600
Re: Sensor wiring Dave Nadler <drn@nadler.com> - 2013-10-01 13:36 -0700
Re: Sensor wiring Dave Nadler <drn@nadler.com> - 2013-10-01 13:39 -0700
Re: Sensor wiring Vladimir Vassilevsky <nospam@nowhere.com> - 2013-09-30 16:58 -0500
Re: Sensor wiring Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-10-01 08:44 +0200
Re: Sensor wiring upsidedown@downunder.com - 2013-10-01 10:02 +0300
Re: Sensor wiring Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-10-01 09:11 +0100
Re: Sensor wiring Paul Rubin <no.email@nospam.invalid> - 2013-10-01 00:36 -0700
Re: Sensor wiring Paul E Bennett <Paul_E.Bennett@topmail.co.uk> - 2013-10-01 09:19 +0100
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