>> B: would +5V external rather than parasitic powered DS help? >Well, somewhat. The point is that if you use external power the >converter will tell the host when it's done. Otherwise you have to >wait however long a pessimistic estimate of the conversion time is.
>My own measurements were measurably different (and more jittery) with >parasitic power, so I decided not to use it anywhere if possible. >(Some of these devices manage not to *have* a +5V input...) >> C: is a two-second cycle time too short? >> >Well, if I applied a two-second cycle time to all of my devices I'd need >about ten USB interfaces... :-/ hmmm. I seem to recall seeing it done elsewhere (not owfs) as: tell all the temperature sensors to start a conversion wait 300ms read all the sensors this does not work with parasitic power because you cant have more than one sensor getting parasitic power at a time but works fine for direct powered devices. >You might want to use one of the provided libraries instead. >It's much faster and depends on fewer pieces of software you might not >really need, or want, in a production environment. Ah, perhaps the libraries do it this way? HTH ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
