Hello, regarding this 85°C error: it looks like it's not only the power-up state: we get this value everytime we dont wait enought time after requesting a temperature convertion and reading the scratchpad. I did a small program on an arduino connected on a DS18B20, this programm start with a 600ms delay decrease it 1 by 1 down to 580 then set it back to 600. We can see the output here: when we reach 590ms the reading is 85 and will remain at 85 until we set it back to 600.
Temperature = 21.31 Celsius, Time to convert =600 Temperature = 21.37 Celsius, Time to convert =599 Temperature = 21.37 Celsius, Time to convert =598 Temperature = 21.37 Celsius, Time to convert =597 Temperature = 21.37 Celsius, Time to convert =596 Temperature = 21.37 Celsius, Time to convert =595 Temperature = 21.37 Celsius, Time to convert =594 Temperature = 21.37 Celsius, Time to convert =593 Temperature = 21.37 Celsius, Time to convert =592 Temperature = 21.37 Celsius, Time to convert =591 Temperature = 85.00 Celsius, Time to convert =590 Temperature = 85.00 Celsius, Time to convert =589 Temperature = 85.00 Celsius, Time to convert =588 Temperature = 85.00 Celsius, Time to convert =587 Temperature = 85.00 Celsius, Time to convert =586 Temperature = 85.00 Celsius, Time to convert =585 Temperature = 85.00 Celsius, Time to convert =584 Temperature = 85.00 Celsius, Time to convert =583 Temperature = 85.00 Celsius, Time to convert =582 Temperature = 85.00 Celsius, Time to convert =581 Temperature = 21.44 Celsius, Time to convert =600 Temperature = 21.44 Celsius, Time to convert =599 Temperature = 21.44 Celsius, Time to convert =598 Temperature = 21.44 Celsius, Time to convert =597 Here is the code #include <OneWire.h> int TimeToConvert = 600; // OneWire DS18S20, DS18B20, DS1822 Temperature Example // // http://www.pjrc.com/teensy/td_libs_OneWire.html // // The DallasTemperature library can do all this work for you! // http://milesburton.com/Dallas_Temperature_Control_Library OneWire ds(11); // on pin 10 (a 4.7K resistor is necessary) void setup(void) { Serial.begin(9600); } void loop(void) { byte i; byte present = 0; byte type_s; byte data[12]; byte addr[8]; float celsius, fahrenheit; if ( !ds.search(addr)) { Serial.println("No more addresses."); Serial.println(); ds.reset_search(); delay(250); return; } Serial.print("ROM ="); for( i = 0; i < 8; i++) { Serial.write(' '); Serial.print(addr[i], HEX); } if (OneWire::crc8(addr, 7) != addr[7]) { Serial.println("CRC is not valid!"); return; } Serial.println(); // the first ROM byte indicates which chip switch (addr[0]) { case 0x10: Serial.println(" Chip = DS18S20"); // or old DS1820 type_s = 1; break; case 0x28: Serial.println(" Chip = DS18B20"); type_s = 0; break; case 0x22: Serial.println(" Chip = DS1822"); type_s = 0; break; default: Serial.println("Device is not a DS18x20 family device."); return; } ds.reset(); ds.select(addr); ds.write(0x44, 1); // start conversion, with parasite power on at the end delay(TimeToConvert); // maybe 750ms is enough, maybe not // we might do a ds.depower() here, but the reset will take care of it. present = ds.reset(); ds.select(addr); ds.write(0xBE); // Read Scratchpad Serial.print(" Data = "); Serial.print(present, HEX); Serial.print(" "); for ( i = 0; i < 9; i++) { // we need 9 bytes data[i] = ds.read(); Serial.print(data[i], HEX); Serial.print(" "); } Serial.print(" CRC="); Serial.print(OneWire::crc8(data, 8), HEX); Serial.println(); // Convert the data to actual temperature // because the result is a 16 bit signed integer, it should // be stored to an "int16_t" type, which is always 16 bits // even when compiled on a 32 bit processor. int16_t raw = (data[1] << 8) | data[0]; if (type_s) { raw = raw << 3; // 9 bit resolution default if (data[7] == 0x10) { // "count remain" gives full 12 bit resolution raw = (raw & 0xFFF0) + 12 - data[6]; } } else { byte cfg = (data[4] & 0x60); // at lower res, the low bits are undefined, so let's zero them if (cfg == 0x00) raw = raw & ~7; // 9 bit resolution, 93.75 ms else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms //// default is 12 bit resolution, 750 ms conversion time } celsius = (float)raw / 16.0; fahrenheit = celsius * 1.8 + 32.0; Serial.println(""); Serial.print(" Temperature = "); Serial.print(celsius); Serial.print(" Celsius, "); // Serial.print(fahrenheit); // Serial.println(" Fahrenheit"); Serial.print("Time to convert ="); Serial.println(TimeToConvert); TimeToConvert = TimeToConvert-1; if ( TimeToConvert == 580){ TimeToConvert = 600; } } Best regards -- Guy ------------------------------------------------------------------------------ Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San Francisco, CA to explore cutting-edge tech and listen to tech luminaries present their vision of the future. This family event has something for everyone, including kids. Get more information and register today. http://sdm.link/attshape _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
