Phil, As has been said, there is no true alarm interrupt. There are some chips that can have high and low alarms and a polling mode that only sees alarmed sensors.
Still, it is not worth it for me. The cost of doing the actual polling for 30 sensors is fairly low if you first send a simultaneous conversion message to the bus. With this, it takes a second for the first to answer and the rest take well under half a second each to poll. Honestly, the added stuff of setting up the limits and making sure they stay set is far more than the effort of polling. The more state I have outside my software, the more setup complexity I have in code that is less exercised/tested. Also, for my control system the target settings can be dynamic relative to the situation, so that drives up complexity having external state. If things start taking too long, it is easy to put another bus master in and do the simultaneous and poll for each bus separately (this is what I do.) OWFS has good threading support. Now for someone who has static targets, hundreds of sensor on a single bus and only a few in alarm, this could be worth it. This is just my $.02. jerry On 06/12/2012 05:36 PM, Phil White wrote: > Hi All, > > This may, or may not, be applicable to this list. However, I am hoping > that someone here knows enough about MicroLAN to be able to clarify > something for me. > > Up to know, all my sensors have been polled. Simplistically speaking, > the PC asks "What is the temperature now?" > > What I am pondering is the ability for a sensor to suddenly, without > any warning, say "Gosh! It's hot here". > > Now, some of the iButtons come with a feature called a Presence Pulse > - although I am also interested in getting events via a DS2408 switch, > and the DS18B20 comes with an alarm function. > > Questions: > Is this possible (preferable, but not necessarily, with OWFS) without > polling the chip all the time? > what are my options? > > Many thanks > > Phil > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Owfs-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/owfs-developers ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
