MPL3115A2 for Micropython

MicroPython/mpl3115a2.py

@@ -0,0 +1,137 @@
+
+
+import time
+from machine import I2C, Pin
+
+ALTITUDE = const(0)
+PRESSURE = const(1)
+
+
+class MPL3115A2exception(Exception):
+    pass
+
+
+class MPL3115A2:
+    MPL3115_I2CADDR = const(0x60)
+    MPL3115_STATUS = const(0x00)
+    MPL3115_PRESSURE_DATA_MSB = const(0x01)
+    MPL3115_PRESSURE_DATA_CSB = const(0x02)
+    MPL3115_PRESSURE_DATA_LSB = const(0x03)
+    MPL3115_TEMP_DATA_MSB = const(0x04)
+    MPL3115_TEMP_DATA_LSB = const(0x05)
+    MPL3115_DR_STATUS = const(0x06)
+    MPL3115_DELTA_DATA = const(0x07)
+    MPL3115_WHO_AM_I = const(0x0c)
+    MPL3115_FIFO_STATUS = const(0x0d)
+    MPL3115_FIFO_DATA = const(0x0e)
+    MPL3115_FIFO_SETUP = const(0x0e)
+    MPL3115_TIME_DELAY = const(0x10)
+    MPL3115_SYS_MODE = const(0x11)
+    MPL3115_INT_SORCE = const(0x12)
+    MPL3115_PT_DATA_CFG = const(0x13)
+    MPL3115_BAR_IN_MSB = const(0x14)
+    MPL3115_P_ARLARM_MSB = const(0x16)
+    MPL3115_T_ARLARM = const(0x18)
+    MPL3115_P_ARLARM_WND_MSB = const(0x19)
+    MPL3115_T_ARLARM_WND = const(0x1b)
+    MPL3115_P_MIN_DATA = const(0x1c)
+    MPL3115_T_MIN_DATA = const(0x1f)
+    MPL3115_P_MAX_DATA = const(0x21)
+    MPL3115_T_MAX_DATA = const(0x24)
+    MPL3115_CTRL_REG1 = const(0x26)
+    MPL3115_CTRL_REG2 = const(0x27)
+    MPL3115_CTRL_REG3 = const(0x28)
+    MPL3115_CTRL_REG4 = const(0x29)
+    MPL3115_CTRL_REG5 = const(0x2a)
+    MPL3115_OFFSET_P = const(0x2b)
+    MPL3115_OFFSET_T = const(0x2c)
+    MPL3115_OFFSET_H = const(0x2d)
+
+    def __init__(self, sda=Pin(21), scl=Pin(22), mode=PRESSURE):
+
+        self.i2c = I2C(scl=scl, sda=sda, freq=100000)
+        self.STA_reg = bytearray(1)
+        self.mode = mode
+
+        if self.mode is PRESSURE:
+            # barometer mode, not raw, oversampling 128, minimum time 512 ms
+            self.i2c.writeto_mem(
+                MPL3115_I2CADDR, MPL3115_CTRL_REG1, bytes([0x38]))
+            self.i2c.writeto_mem(MPL3115_I2CADDR, MPL3115_PT_DATA_CFG, bytes(
+                [0x07]))  # no events detected
+            self.i2c.writeto_mem(
+                MPL3115_I2CADDR, MPL3115_CTRL_REG1, bytes([0x39]))  # active
+        elif self.mode is ALTITUDE:
+            # altitude mode, not raw, oversampling 128, minimum time 512 ms
+            self.i2c.writeto_mem(
+                MPL3115_I2CADDR, MPL3115_CTRL_REG1, bytes([0xB8]))
+            self.i2c.writeto_mem(MPL3115_I2CADDR, MPL3115_PT_DATA_CFG, bytes(
+                [0x07]))  # no events detected
+            self.i2c.writeto_mem(
+                MPL3115_I2CADDR, MPL3115_CTRL_REG1, bytes([0xB9]))  # active
+        else:
+            raise MPL3115A2exception("Invalid Mode MPL3115A2")
+
+        if self._read_status():
+            pass
+        else:
+            raise MPL3115A2exception("Error with MPL3115A2")
+
+    def _read_status(self):
+        while True:
+            self.i2c.readfrom_mem_into(
+                MPL3115_I2CADDR, MPL3115_STATUS, self.STA_reg)
+
+            if(self.STA_reg[0] == 0):
+                time.sleep(0.01)
+                pass
+            elif(self.STA_reg[0] & 0x04) == 4:
+                return True
+            else:
+                return False
+
+    def pressure(self):
+        if self.mode == ALTITUDE:
+            raise MPL3115A2exception("Incorrect Measurement Mode MPL3115A2")
+
+        OUT_P_MSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_PRESSURE_DATA_MSB, 1)
+        OUT_P_CSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_PRESSURE_DATA_CSB, 1)
+        OUT_P_LSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_PRESSURE_DATA_LSB, 1)
+
+        return float((OUT_P_MSB[0] << 10) + (OUT_P_CSB[0] << 2) + ((OUT_P_LSB[0] >> 6) & 0x03) + ((OUT_P_LSB[0] >> 4) & 0x03) / 4.0)
+
+    def altitude(self):
+        if self.mode == PRESSURE:
+            raise MPL3115A2exception("Incorrect Measurement Mode MPL3115A2")
+
+        OUT_P_MSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_PRESSURE_DATA_MSB, 1)
+        OUT_P_CSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_PRESSURE_DATA_CSB, 1)
+        OUT_P_LSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_PRESSURE_DATA_LSB, 1)
+
+        alt_int = (OUT_P_MSB[0] << 8) + (OUT_P_CSB[0])
+        alt_frac = ((OUT_P_LSB[0] >> 4) & 0x0F)
+
+        if alt_int > 32767:
+            alt_int -= 65536
+
+        return float(alt_int + alt_frac / 16.0)
+
+    def temperature(self):
+        OUT_T_MSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_TEMP_DATA_MSB, 1)
+        OUT_T_LSB = self.i2c.readfrom_mem(
+            MPL3115_I2CADDR, MPL3115_TEMP_DATA_LSB, 1)
+
+        temp_int = OUT_T_MSB[0]
+        temp_frac = OUT_T_LSB[0]
+
+        if temp_int > 127:
+            temp_int -= 256
+
+        return float(temp_int + temp_frac / 256.0)