yryz / ds18b20 Goto Github PK

Summary:
This library does not validate that a correct temperature was obtained. Note this is only to validate that the 1Wire communication was successful; the DS18b20 sensor does not have self-test.

Observed behavior:
The first line of the w1 "file" is a CRC validation of the temperature value.
At this moment, the yryz/ds18b20 library does not validate that the CRC is valid before returning a temperature reading.

Desired behavior:
Expect the CRC tag to be present and "YES" immediately after.
Should this condition fail, return an error.

With all due respect, while I agree (FWIW) with the code in case '0', I question case 'f'.
To try to help, the 2 hex strings (data) I get back from 2 DSs are:
dd ff 4b 46 7f ff 03 10 25 : crc=25 YES
16 00 4b 46 7f ff 0a 10 a5 : crc=a5 YES
The temp is hovering around 0C and have used several DSs, all of which provide reasonably accurate results once the temps rise above about .5 thru 1.5C (w/in variances and compared against other HTU21D and AM2315 probes, as well as WeatherUnderground).