Merge branch 'dannystaple-patch-1'

library/icm20948/__init__.py

@@ -34,6 +34,14 @@
 ICM20948_ACCEL_XOUT_H = 0x2D
 ICM20948_GRYO_XOUT_H = 0x33
 
+ICM20948_TEMP_OUT_H = 0x39
+ICM20948_TEMP_OUT_L = 0x3A
+
+# Offset and sensitivity - defined in electrical characteristics, and TEMP_OUT_H/L of datasheet
+ICM20948_TEMPERATURE_DEGREES_OFFSET = 21
+ICM20948_TEMPERATURE_SENSITIVITY = 333.87
+ICM20948_ROOM_TEMP_OFFSET = 21
+
 AK09916_I2C_ADDR = 0x0c
 AK09916_CHIP_ID = 0x09
 AK09916_WIA = 0x01
@@ -209,6 +217,15 @@ def set_gyro_low_pass(self, enabled=True, mode=5):
         value |= (mode & 0x07) << 4
         self.write(ICM20948_GYRO_CONFIG_1, value)
 
+    def read_temperature(self):
+        """Property to read the current IMU temperature"""
+        # PWR_MGMT_1 defaults to leave temperature enabled
+        self.bank(0)
+        temp_raw_bytes = self.read_bytes(ICM20948_TEMP_OUT_H, 2)
+        temp_raw = struct.unpack('>h', bytearray(temp_raw_bytes))[0]
+        temperature_deg_c = ((temp_raw - ICM20948_ROOM_TEMP_OFFSET) / ICM20948_TEMPERATURE_SENSITIVITY) + ICM20948_TEMPERATURE_DEGREES_OFFSET
+        return temperature_deg_c
+
     def __init__(self, i2c_addr=I2C_ADDR, i2c_bus=None):
         self._bank = -1
         self._addr = i2c_addr

library/tests/test_read.py

@@ -13,3 +13,13 @@ def test_accel_gyro():
     ax, ay, az, gx, gy, gz = icm20948.read_accelerometer_gyro_data()
     assert (round(ax, 2), round(ay, 2), round(az, 2), int(gx), int(gy), int(gz)) == (0.05, 0.11, 0.16, 3, 4, 5)
     del icm20948
+
+def test_temperature():
+    smbus = mock.Mock()
+    smbus.SMBus = MockSMBus
+    sys.modules['smbus'] = smbus
+
+    from icm20948 import ICM20948
+    icm20948 = ICM20948()
+    temp_degrees = icm20948.read_temperature()
+    assert (round(temp_degrees, 2) == 24)

library/tests/tools.py

@@ -34,3 +34,6 @@ def read_i2c_block_data(self, addr, reg, length):
                 555,
                 666
             ))
+        # temperature data
+        if length == 2:
+            return struct.pack(">h", 0x400)