Go Down

Topic: 1-Wire, DS18B20... How do I search the bus? (Read 58561 times) previous topic - next topic


I used 4.7k standard pull-up for 1Wire device bus. I don't tested under chilled temperatures. But 26uS gives correct reads >127 C degrees with DS18B20's without single bit of error with both powered & parasite power connections... I don't wait different results under -55 C degrees. It might change it's characteristic on different batches  +- 1 or 2 uS. But there is ~10uS margin surely will protects us. So +1uS will not arise trouble.

At my situation, I think it's required to use higher value of resistor since I wanted to longer "0" pulses, not shorter one, that slow downs line pull-up. I can turn around this problem on my local setup via using altered OneWire library code or electronically by using new resister.  But I just wanted to make Arduino's OneWire library more compatible with OneWire spec. At least, please think about adjusting reading time to 14uS that matches with DS18B20 master sample time.

Go Up