bme280*.py: Use names for the power modes.

README.md

@@ -92,10 +92,10 @@ Copy `bme280_float.py` onto the board. Then:
 # On pycom devuces that is P9 = SDA, P10 = scl
 #
 import machine
-import bme280_float
+import bme280_float as bme280
 
 i2c = machine.I2C()
-bme = bme280_float.BME280(i2c=i2c)
+bme = bme280.BME280(i2c=i2c)
 
 print(bme.values)
 ```

bme280_float.py

@@ -58,6 +58,9 @@ BME280_REGISTER_CONTROL_HUM = 0xF2
 BME280_REGISTER_STATUS = 0xF3
 BME280_REGISTER_CONTROL = 0xF4
 
+MODE_SLEEP = const(0)
+MODE_FORCED = const(1)
+MODE_NORMAL = const(3)
 
 class BME280:
 
@@ -95,15 +98,16 @@ class BME280:
         self.dig_H4 = (self.dig_H4 * 16) + (self.dig_H5 & 0xF)
         self.dig_H5 //= 16
 
-        self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL,
-                             bytearray([0x3F]))
-        self.t_fine = 0
-
         # temporary data holders which stay allocated
         self._l1_barray = bytearray(1)
         self._l8_barray = bytearray(8)
         self._l3_resultarray = array("i", [0, 0, 0])
 
+        self._l1_barray[0] = self._mode << 5 | self._mode << 2 | MODE_SLEEP
+        self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL,
+                             self._l1_barray)
+        self.t_fine = 0
+
     def read_raw_data(self, result):
         """ Reads the raw (uncompensated) data from the sensor.
 
@@ -117,7 +121,7 @@ class BME280:
         self._l1_barray[0] = self._mode
         self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL_HUM,
                              self._l1_barray)
-        self._l1_barray[0] = self._mode << 5 | self._mode << 2 | 1
+        self._l1_barray[0] = self._mode << 5 | self._mode << 2 | MODE_FORCED
         self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL,
                              self._l1_barray)
 

bme280_int.py

@@ -62,6 +62,10 @@ BME280_REGISTER_CONTROL_HUM = 0xF2
 BME280_REGISTER_STATUS = 0xF3
 BME280_REGISTER_CONTROL = 0xF4
 
+MODE_SLEEP = const(0)
+MODE_FORCED = const(1)
+MODE_NORMAL = const(3)
+
 
 class BME280:
 
@@ -98,8 +102,6 @@ class BME280:
         self.dig_H4 = (self.dig_H4 * 16) + (self.dig_H5 & 0xF)
         self.dig_H5 //= 16
 
-        self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL,
-                             bytearray([0x3F]))
         self.t_fine = 0
 
         # temporary data holders which stay allocated
@@ -107,6 +109,10 @@ class BME280:
         self._l8_barray = bytearray(8)
         self._l3_resultarray = array("i", [0, 0, 0])
 
+        self._l1_barray[0] = self._mode << 5 | self._mode << 2 | MODE_SLEEP
+        self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL,
+                             bytearray([0x3c | MODE_SLEEP]))
+
     def read_raw_data(self, result):
         """ Reads the raw (uncompensated) data from the sensor.
 
@@ -120,7 +126,7 @@ class BME280:
         self._l1_barray[0] = self._mode
         self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL_HUM,
                              self._l1_barray)
-        self._l1_barray[0] = self._mode << 5 | self._mode << 2 | 1
+        self._l1_barray[0] = self._mode << 5 | self._mode << 2 | MODE_FORCED
         self.i2c.writeto_mem(self.address, BME280_REGISTER_CONTROL,
                              self._l1_barray)
 

bmetest.py

@@ -3,7 +3,10 @@
 #
 from machine import I2C
 from bme280 import *
+from utime import sleep
 i2c=I2C()
 bme280 = BME280(i2c=i2c)
-bme280.values
+while True:
+    print(bme280.values)
+    sleep(1)