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your board may have the newer pressure sensor, BMP388.
Try this code
#!/usr/bin/python # -*- coding: utf-8 -*- import time import smbus import math # define BMP388 Device I2C address I2C_ADD_BMP388_AD0_LOW = 0x76 I2C_ADD_BMP388_AD0_HIGH = 0x77 I2C_ADD_BMP388 = I2C_ADD_BMP388_AD0_HIGH BMP388_REG_ADD_WIA = 0x00 BMP388_REG_VAL_WIA = 0x50 BMP388_REG_ADD_ERR = 0x02 BMP388_REG_VAL_FATAL_ERR = 0x01 BMP388_REG_VAL_CMD_ERR = 0x02 BMP388_REG_VAL_CONF_ERR = 0x04 BMP388_REG_ADD_STATUS = 0x03 BMP388_REG_VAL_CMD_RDY = 0x10 BMP388_REG_VAL_DRDY_PRESS = 0x20 BMP388_REG_VAL_DRDY_TEMP = 0x40 BMP388_REG_ADD_CMD = 0x7E BMP388_REG_VAL_EXTMODE_EN = 0x34 BMP388_REG_VAL_FIFI_FLUSH = 0xB0 BMP388_REG_VAL_SOFT_RESET = 0xB6 BMP388_REG_ADD_PWR_CTRL = 0x1B BMP388_REG_VAL_PRESS_EN = 0x01 BMP388_REG_VAL_TEMP_EN = 0x02 BMP388_REG_VAL_NORMAL_MODE = 0x30 BMP388_REG_ADD_PRESS_XLSB = 0x04 BMP388_REG_ADD_PRESS_LSB = 0x05 BMP388_REG_ADD_PRESS_MSB = 0x06 BMP388_REG_ADD_TEMP_XLSB = 0x07 BMP388_REG_ADD_TEMP_LSB = 0x08 BMP388_REG_ADD_TEMP_MSB = 0x09 BMP388_REG_ADD_T1_LSB = 0x31 BMP388_REG_ADD_T1_MSB = 0x32 BMP388_REG_ADD_T2_LSB = 0x33 BMP388_REG_ADD_T2_MSB = 0x34 BMP388_REG_ADD_T3 = 0x35 BMP388_REG_ADD_P1_LSB = 0x36 BMP388_REG_ADD_P1_MSB = 0x37 BMP388_REG_ADD_P2_LSB = 0x38 BMP388_REG_ADD_P2_MSB = 0x39 BMP388_REG_ADD_P3 = 0x3A BMP388_REG_ADD_P4 = 0x3B BMP388_REG_ADD_P5_LSB = 0x3C BMP388_REG_ADD_P5_MSB = 0x3D BMP388_REG_ADD_P6_LSB = 0x3E BMP388_REG_ADD_P6_MSB = 0x3F BMP388_REG_ADD_P7 = 0x40 BMP388_REG_ADD_P8 = 0x41 BMP388_REG_ADD_P9_LSB = 0x42 BMP388_REG_ADD_P9_MSB = 0x43 BMP388_REG_ADD_P10 = 0x44 BMP388_REG_ADD_P11 = 0x45 class BMP388(object): """docstring for BMP388""" def __init__(self, address=I2C_ADD_BMP388): self._address = address self._bus = smbus.SMBus(0x01) # Load calibration values. if self._read_byte(BMP388_REG_ADD_WIA) == BMP388_REG_VAL_WIA: print("Pressure sersor is BMP388!\r\n") u8RegData = self._read_byte(BMP388_REG_ADD_STATUS) if u8RegData & BMP388_REG_VAL_CMD_RDY: self._write_byte(BMP388_REG_ADD_CMD, BMP388_REG_VAL_SOFT_RESET) time.sleep(0.01) else: print ("Pressure sersor NULL!\r\n") self._write_byte(BMP388_REG_ADD_PWR_CTRL, BMP388_REG_VAL_PRESS_EN | BMP388_REG_VAL_TEMP_EN | BMP388_REG_VAL_NORMAL_MODE) self._load_calibration() def _read_byte(self, cmd): return self._bus.read_byte_data(self._address, cmd) def _read_s8(self, cmd): result = self._read_byte(cmd) if result > 128: result -= 256 return result def _read_u16(self, cmd): LSB = self._bus.read_byte_data(self._address, cmd) MSB = self._bus.read_byte_data(self._address, cmd + 0x01) return (MSB << 0x08) + LSB def _read_s16(self, cmd): result = self._read_u16(cmd) if result > 32767: result -= 65536 return result def _write_byte(self, cmd, val): self._bus.write_byte_data(self._address, cmd, val) def _load_calibration(self): print ("_load_calibration\r\n") self.T1 = self._read_u16(BMP388_REG_ADD_T1_LSB) self.T2 = self._read_u16(BMP388_REG_ADD_T2_LSB) self.T3 = self._read_s8(BMP388_REG_ADD_T3) self.P1 = self._read_s16(BMP388_REG_ADD_P1_LSB) self.P2 = self._read_s16(BMP388_REG_ADD_P2_LSB) self.P3 = self._read_s8(BMP388_REG_ADD_P3) self.P4 = self._read_s8(BMP388_REG_ADD_P4) self.P5 = self._read_u16(BMP388_REG_ADD_P5_LSB) self.P6 = self._read_u16(BMP388_REG_ADD_P6_LSB) self.P7 = self._read_s8(BMP388_REG_ADD_P7) self.P8 = self._read_s8(BMP388_REG_ADD_P8) self.P9 = self._read_s16(BMP388_REG_ADD_P9_LSB) self.P10 = self._read_s8(BMP388_REG_ADD_P10) self.P11 = self._read_s8(BMP388_REG_ADD_P11) # print(self.T1) # print(self.T2) # print(self.T3) # print(self.P1) # print(self.P2) # print(self.P3) # print(self.P4) # print(self.P5) # print(self.P6) # print(self.P7) # print(self.P8) # print(self.P9) # print(self.P10) # print(self.P11) def compensate_temperature(self, adc_T): partial_data1 = adc_T - 256 * self.T1 partial_data2 = self.T2 * partial_data1 partial_data3 = partial_data1 * partial_data1 partial_data4 = partial_data3 * self.T3 partial_data5 = partial_data2 * 262144 + partial_data4 partial_data6 = partial_data5 / 4294967296 self.T_fine = partial_data6 comp_temp = partial_data6 * 25 / 16384 return comp_temp def compensate_pressure(self, adc_P): partial_data1 = self.T_fine * self.T_fine partial_data2 = partial_data1 / 0x40 partial_data3 = partial_data2 * self.T_fine / 256 partial_data4 = self.P8 * partial_data3 / 0x20 partial_data5 = self.P7 * partial_data1 * 0x10 partial_data6 = self.P6 * self.T_fine * 4194304 offset = self.P5 * 140737488355328 + partial_data4 \ + partial_data5 + partial_data6 partial_data2 = self.P4 * partial_data3 / 0x20 partial_data4 = self.P3 * partial_data1 * 0x04 partial_data5 = (self.P2 - 16384) * self.T_fine * 2097152 sensitivity = (self.P1 - 16384) * 70368744177664 \ + partial_data2 + partial_data4 + partial_data5 partial_data1 = sensitivity / 16777216 * adc_P partial_data2 = self.P10 * self.T_fine partial_data3 = partial_data2 + 65536 * self.P9 partial_data4 = partial_data3 * adc_P / 8192 partial_data5 = partial_data4 * adc_P / 512 partial_data6 = adc_P * adc_P partial_data2 = self.P11 * partial_data6 / 65536 partial_data3 = partial_data2 * adc_P / 128 partial_data4 = offset / 0x04 + partial_data1 + partial_data5 \ + partial_data3 comp_press = partial_data4 * 25 / 1099511627776 return comp_press def get_temperature_and_pressure_and_altitude(self): """Returns pressure in Pa as double. Output value of "6386.2"equals 96386.2 Pa = 963.862 hPa.""" xlsb = self._read_byte(BMP388_REG_ADD_TEMP_XLSB) lsb = self._read_byte(BMP388_REG_ADD_TEMP_LSB) msb = self._read_byte(BMP388_REG_ADD_TEMP_MSB) adc_T = (msb << 0x10) + (lsb << 0x08) + xlsb temperature = self.compensate_temperature(adc_T) xlsb = self._read_byte(BMP388_REG_ADD_PRESS_XLSB) lsb = self._read_byte(BMP388_REG_ADD_PRESS_LSB) msb = self._read_byte(BMP388_REG_ADD_PRESS_MSB) adc_P = (msb << 0x10) + (lsb << 0x08) + xlsb pressure = self.compensate_pressure(adc_P) altitude = 4433000 * (0x01 - pow(pressure / 100.0 / 101325.0, 0.1903)) return (temperature, pressure, altitude) if __name__ == '__main__': import time print("BMP388 Test Program ...\n") bmp388 = BMP388() while True: time.sleep(0.5) temperature,pressure,altitude = bmp388.get_temperature_and_pressure_and_altitude() print(' Temperature = %.1f Pressure = %.2f Altitude =%.2f '%(temperature/100.0,pressure/100.0,altitude/100.0))Peter --OzzMaker.com --
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