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From: Paul A. <pau...@gm...> - 2008-07-13 03:28:57
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Your second use i the correct one. Write "1" to simultaneous to trigger a conversion. That also clears the cache. A normal read will read immeadiately the already measured temperature ready in the device. Paul Alfille On Sat, Jul 12, 2008 at 8:28 PM, Doug Collinge <dou...@gm...> wrote: > I'm writing myself a little Python code here and trying to use > 'simultaneous' but getting results that are inconsistent with my > understanding. > > I have multiple DS1820 devices on a bus. They are all powered devices. I > want to simultaneously convert them all, wait, then read them all. I'm > expecting that when I go to read them, since I have signalled a simultaneous > conversion, that they will all be already converted and ready to send their > data, .except perhaps the first one if I haven't waited long enough for the > conversion. > > I'm writing a 1 to '/simultaneous', processing some other stuff, then > reading them all. If I read from '/uncached/temperature' it takes > 600-some-odd milliseconds to read each one, which sounds like they are all > doing a fresh conversion. If I read from '/temperature' then I get them > read in much faster but I don't get a fresh conversion each time. > > What I want is for writing to '/simultaneous' to always kick off a fresh > conversion of all the devices so that I always get a new sample when I read > them, and never take data out of the cache. How can I accomplish this? > > ------------------------------------------------------------------------- > Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! > Studies have shown that voting for your favorite open source project, > along with a healthy diet, reduces your potential for chronic lameness > and boredom. Vote Now at http://www.sourceforge.net/community/cca08 > _______________________________________________ > Owfs-developers mailing list > Owf...@li... > https://lists.sourceforge.net/lists/listinfo/owfs-developers > > |