drivers/hts221: Add HTS221 humidity sensor driver.

drivers/hts221/hts221.py

@@ -0,0 +1,91 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2013-2022 Ibrahim Abdelkader <iabdalkader@openmv.io>
+Copyright (c) 2013-2022 Kwabena W. Agyeman <kwagyeman@openmv.io>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+HTS221 driver driver for MicroPython.
+Original source: https://github.com/ControlEverythingCommunity/HTS221/blob/master/Python/HTS221.py
+
+Example usage:
+
+import time
+import hts221
+from machine import Pin, I2C
+
+bus = I2C(1, scl=Pin(15), sda=Pin(14))
+hts = hts221.HTS221(bus)
+
+while (True):
+    rH   = hts.humidity()
+    temp = hts.temperature()
+    print ("rH: %.2f%% T: %.2fC" %(rH, temp))
+    time.sleep_ms(100)
+"""
+
+import struct
+
+
+class HTS221:
+    def __init__(self, i2c, data_rate=1, address=0x5F):
+        self.bus = i2c
+        self.odr = data_rate
+        self.slv_addr = address
+
+        # Set configuration register
+        # Humidity and temperature average configuration
+        self.bus.writeto_mem(self.slv_addr, 0x10, b"\x1B")
+
+        # Set control register
+        # PD | BDU | ODR
+        cfg = 0x80 | 0x04 | (self.odr & 0x3)
+        self.bus.writeto_mem(self.slv_addr, 0x20, bytes([cfg]))
+
+        # Read Calibration values from non-volatile memory of the device
+        # Humidity Calibration values
+        self.H0 = self._read_reg(0x30, 1) / 2
+        self.H1 = self._read_reg(0x31, 1) / 2
+        self.H2 = self._read_reg(0x36, 2)
+        self.H3 = self._read_reg(0x3A, 2)
+
+        # Temperature Calibration values
+        raw = self._read_reg(0x35, 1)
+        self.T0 = ((raw & 0x03) * 256) + self._read_reg(0x32, 1)
+        self.T1 = ((raw & 0x0C) * 64) + self._read_reg(0x33, 1)
+        self.T2 = self._read_reg(0x3C, 2)
+        self.T3 = self._read_reg(0x3E, 2)
+
+    def _read_reg(self, reg_addr, size):
+        fmt = "B" if size == 1 else "H"
+        reg_addr = reg_addr if size == 1 else reg_addr | 0x80
+        return struct.unpack(fmt, self.bus.readfrom_mem(self.slv_addr, reg_addr, size))[0]
+
+    def humidity(self):
+        rH = self._read_reg(0x28, 2)
+        return (self.H1 - self.H0) * (rH - self.H2) / (self.H3 - self.H2) + self.H0
+
+    def temperature(self):
+        temp = self._read_reg(0x2A, 2)
+        if temp > 32767:
+            temp -= 65536
+        return ((self.T1 - self.T0) / 8.0) * (temp - self.T2) / (self.T3 - self.T2) + (
+            self.T0 / 8.0
+        )