def _mag_callback(self): ''' Update magnetometer Vector3d object (if data available) ''' try: # If read fails, returns last valid data if self.mag_ready: # Starts mag if necessary self._read(self.buf6, 0x03, self._mag_addr) self.mag_triggered = False else: self._mag_stale_count += 1 # Data not ready: retain last value return # but increment stale count self._read(self.buf6, 0x03, self._mag_addr) # Mag was ready self._read(self.buf1, 0x09, self._mag_addr) # Read ST2 except OSError: self.mag_triggered = False raise MPUException(self._I2Cerror) if self.buf1[0] & 0x0C > 0: # An overflow or data error has occurred self._mag_stale_count += 1 # transitory condition? User checks stale count. return self._mag._ivector[1] = bytes_toint( self.buf6[1], self.buf6[0]) # Note axis twiddling and little endian self._mag._ivector[0] = bytes_toint(self.buf6[3], self.buf6[2]) self._mag._ivector[2] = -bytes_toint(self.buf6[5], self.buf6[4]) scale = 0.3 # 0.3uT/LSB self._mag._vector[ 0] = self._mag._ivector[0] * self.mag_correction[0] * scale self._mag._vector[ 1] = self._mag._ivector[1] * self.mag_correction[1] * scale self._mag._vector[ 2] = self._mag._ivector[2] * self.mag_correction[2] * scale self._mag_stale_count = 0
def temperature(self): ''' Returns the temperature in degree C. ''' try: self._read(self.buf2, 0x41, self.mpu_addr) except OSError: raise MPUException(self._I2Cerror) return bytes_toint(self.buf2[0], self.buf2[1]) / 340 + 35 # I think
def mag_ready(self): ''' Initiates a reading if necessary. Returns ready state. ''' self.mag_trigger() try: self._read(self.buf1, 0x02, self._mag_addr) except OSError: raise MPUException(self._I2Cerror) return bool(self.buf1[0] & 1)
def mag_trigger(self): ''' Initiate a mag reading. Can be called repeatedly. ''' if not self.mag_triggered: try: self._write(0x01, 0x0A, self._mag_addr) # single measurement mode except OSError: raise MPUException(self._I2Cerror) self.mag_triggered = True
def filter_range(self): ''' Returns the gyro and temperature sensor low pass filter cutoff frequency Pass: 0 1 2 3 4 5 6 Cutoff (Hz): 250 184 92 41 20 10 5 Sample rate (KHz): 8 1 1 1 1 1 1 ''' try: self._read(self.buf1, 0x1A, self.mpu_addr) res = self.buf1[0] & 7 except OSError: raise MPUException(self._I2Cerror) return res
def _magsetup(self): ''' Read magnetometer correction values from ROM. Perform the maths as decribed on page 59 of register map and store the results. ''' try: self._write(0x0F, 0x0A, self._mag_addr) self._read(self.buf3, 0x10, self._mag_addr) self._write(0, 0x0A, self._mag_addr) # Power down mode except OSError: raise MPUException(self._I2Cerror) mag_x = (0.5 * (self.buf3[0] - 128)) / 128 + 1 mag_y = (0.5 * (self.buf3[1] - 128)) / 128 + 1 mag_z = (0.5 * (self.buf3[2] - 128)) / 128 + 1 return (mag_x, mag_y, mag_z)
def filter_range(self, filt): ''' Sets the gyro and temperature sensor low pass filter cutoff frequency Pass: 0 1 2 3 4 5 6 Cutoff (Hz): 250 184 92 41 20 10 5 Sample rate (KHz): 8 1 1 1 1 1 1 ''' # set range if filt in range(7): try: self._write(filt, 0x1A, self.mpu_addr) except OSError: raise MPUException(self._I2Cerror) else: raise ValueError('Filter coefficient must be between 0 and 6')