maybe the configuration eeprom register could help... when we read with 9 bits we could change eeprom to 10 bits, set current to 9bits execute conversion algorithm the eeprom configuration never could be = current conversion bit, or we know that device was reseted and the 85 degree is wrong
there's a way to read eeprom value, and the current value? or ds18X20 don't allow this? Em 29 de fevereiro de 2012 23:30, Roberto Spadim <[email protected]> escreveu: > yes, well i think owfs is doing 1second wait time of pullup with > serial-onewire dallas converter (i don't remeber it exactly i think > it's ds2480b) > > the question is... it's works but sometimes it work wrongly > i was thinking something like... > > write alarm high temperature of user value to eeprom and to current memory > change eeprom to uservalue+1 > when device is reseted eeprom=current memory > this time we know that device reseted and the 85 value is wrong > > it's ugly but since ds18b20 don't have a user bit to save information > at eeprom... i think it's a solution (maybe not a good one) that > remove 85 degree error > > > Em 29 de fevereiro de 2012 23:17, Eric Vickery > <[email protected]> escreveu: >> Even if they are powered you have to make sure you are waiting long enough >> before taking a reading >> after a temperature convert. At 12bits the DS18B20 takes as long as the >> DS18S20 (around 750mS). >> >> On 2/29/2012 8:12 PM, Roberto Spadim wrote: >>> yes hehe my is the second, i connect 5v, 0v and owbus >>> does ds18b20 have a crc or another feature that shows the reset status >>> or something else? i could check for example.... >>> read 85 degree >>> read the crc value (or another reset value) >>> start of infinite loop: >>> read 85 degree again >>> read the crc value (or another reset value) >>> if crc value = reset value, loop, else good read >>> >>> i don't know if exists a reset counter or something like it in >>> ds18b20, does anyone know? >>> >>> >>> Em 29 de fevereiro de 2012 23:07, Eloy Paris<[email protected]> escreveu: >>>> Hi Roberto, >>>> >>>> >>>> On 02/29/2012 08:31 PM, Roberto Spadim wrote: >>>> >>>>> hi guys, i'm having a lot of problem with ds18b20 and 85 degree reads >>>>> what are every body doing when this occur? >>>>> today i read to times when this occur, and if it's 85 em both i allow 85 >>>>> degree >>>>> anyone know another good solution? >>>> >>>> If parasitic powered make sure that Vdd is connected to ground instead of >>>> leaving it floating. If they are being powered then I am afraid I don't >>>> have >>>> a good suggestion :-( >>>> >>>> Cheers, >>>> >>>> Eloy Paris.- >>>> >>>> >>>> >>> >>> >> >> ------------------------------------------------------------------------------ >> Virtualization & Cloud Management Using Capacity Planning >> Cloud computing makes use of virtualization - but cloud computing >> also focuses on allowing computing to be delivered as a service. >> http://www.accelacomm.com/jaw/sfnl/114/51521223/ >> _______________________________________________ >> Owfs-developers mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/owfs-developers >> > > > > -- > Roberto Spadim > Spadim Technology / SPAEmpresarial -- Roberto Spadim Spadim Technology / SPAEmpresarial ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
