fix hangs due to HTS221 and speed upthe humidity readings

Author: Rocketct

src/MKRENV.cpp

@@ -87,7 +87,7 @@ int ENVClass::begin()
   readHTS221Calibration();
 
   // enable HTS221
-  i2cWrite(HTS221_ADDRESS, HTS221_CTRL1_REG, 0x80);
+  i2cWrite(HTS221_ADDRESS, HTS221_CTRL1_REG, 0x84);
 
   // configure VEML6075 for 100 ms
   i2cWriteWord(VEML6075_ADDRESS, VEML6075_UV_CONF_REG, 0x0010);
@@ -100,8 +100,6 @@ void ENVClass::end()
   // shutdown VEML6075
   i2cWriteWord(VEML6075_ADDRESS, VEML6075_UV_CONF_REG, 0x0001);
 
-  delay(80);
-
   // disable HTS221
   i2cWrite(HTS221_ADDRESS, HTS221_CTRL1_REG, 0x00);
 
@@ -113,6 +111,9 @@ void ENVClass::end()
 
 float ENVClass::readTemperature(int units)
 {
+  // Wait for trigger a new read operation
+  while (i2cRead(HTS221_ADDRESS, HTS221_CTRL2_REG) & 0x01);
+
   // trigger one shot
   i2cWrite(HTS221_ADDRESS, HTS221_CTRL2_REG, 0x01);
 
@@ -133,6 +134,9 @@ float ENVClass::readTemperature(int units)
 
 float ENVClass::readHumidity()
 {
+  // Wait for trigger a new read operation
+  while (i2cRead(HTS221_ADDRESS, HTS221_CTRL2_REG) & 0x01);
+
   // trigger one shot
   i2cWrite(HTS221_ADDRESS, HTS221_CTRL2_REG, 0x01);
 
@@ -143,8 +147,8 @@ float ENVClass::readHumidity()
 
   // read value and convert
   int16_t hout = i2cRead16(HTS221_ADDRESS, HTS221_HUMIDITY_OUT_L_REG);
-
-  return (hout * _hts221HumiditySlope + _hts221HumidityZero);
+  float reading = hout * _hts221HumiditySlope + _hts221HumidityZero;
+  return reading;
 }
 
 float ENVClass::readPressure(int units)