To follow up on this post: I missed the i2c pullup on the same pin, which makes the effective pullup lower. When I remove this extra pullup, the reported temperature is 127 degrees (and crc is still correct). I also notice that the dataline is at 2V for 600ms after conversion is initiated. After that it is 5V. This means the sensor draws about 0.6mA on this pin although the vdd pin is connected. (With the i2c pullup of 4k7, the voltage is 3.5V, so same current). So this might be a hardware issue. Maybe the chip thinks it is in parasite mode? As far as I can see it should not, since pin3 is connected to 5V...
Joep 2011/1/16 Joep Suijs <[email protected]>: > Hi, > > @kiste > >> ... Then joep's sensor never has the time to complete a single conversion, >> while vasile's has. > Thought of that too, but I see no reason why the processing takes > significant time in the program that works for Vasi. > > @Vasi >> I can't do better than this :( > You've done a lot, thanks! > > @Vasile > It says ds16b20 on the case (but maybe there are different versions). > Conneciton is 3-wire, less than 15 cm in length. Pull-up is 4k7 and > 100nf over the power supply. > > Most important is the library is working. It's anoyning that we don't > know why it behaves different, but I've run out of time and ideas... > > Joep > -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
