Merge branch 'master' of https://gitee.com/bnu_mixly/mixly3

boards/default_src/micropython/origin/build/lib/sht20.py

@@ -0,0 +1,31 @@
+from struct import unpack as unp
+from time import sleep_ms
+
+# SHT20 default address
+SHT20_I2CADDR = 64
+TRI_T_MEASURE_NO_HOLD = b'\xf3'
+TRI_RH_MEASURE_NO_HOLD = b'\xf5'
+READ_USER_REG = b'\xe7'
+WRITE_USER_REG = b'\xe6'
+SOFT_RESET = b'\xfe'
+
+class SHT20(object):
+    def __init__(self, i2c_bus):
+        self._address = SHT20_I2CADDR
+        self._bus = i2c_bus
+
+    def get_SHT_temperature(self):
+        self._bus.writeto(self._address, TRI_T_MEASURE_NO_HOLD)
+        sleep_ms(150)
+        origin_data = self._bus.readfrom(self._address, 2)
+        origin_value = unp('>h', origin_data)[0]
+        value = -46.85 + 175.72 * (origin_value / 65536)
+        return value
+
+    def get_SHT_relative_humidity(self):
+        self._bus.writeto(self._address, TRI_RH_MEASURE_NO_HOLD)
+        sleep_ms(150)
+        origin_data = self._bus.readfrom(self._address, 2)
+        origin_value = unp('>H', origin_data)[0]
+        value = -6 + 125 * (origin_value / 65536)
+        return value