esp8266/modules: Fix negative temperature in ds18x20 driver.

2016-10-31 10:54:44 +01:00 · 2016-10-31 10:54:44 +01:00 · e5f06559e6
parent 10bde6933e
commit e5f06559e6
1 changed files with 4 additions and 1 deletions
--- a/esp8266/modules/ds18x20.py
+++ b/esp8266/modules/ds18x20.py
@ -43,4 +43,7 @@ class DS18X20:
                t = buf[0] >> 1
            return t - 0.25 + (buf[7] - buf[6]) / buf[7]
        else:
-            return (buf[1] << 8 | buf[0]) / 16
+            t = buf[1] << 8 | buf[0]
+            if t & 0x8000: # sign bit set
+                t = -((t ^ 0xffff) + 1)
+            return t / 16