163 lines
5.7 KiB
Python
163 lines
5.7 KiB
Python
from ustruct import unpack as unp
|
|
import utime
|
|
|
|
# Power Modes
|
|
NORMAL = 0
|
|
BMP280_TEMP_OS_SKIP = 0
|
|
BMP280_TEMP_OS_1 = 1
|
|
BMP280_TEMP_OS_2 = 2
|
|
BMP280_TEMP_OS_4 = 3
|
|
BMP280_TEMP_OS_8 = 4
|
|
BMP280_TEMP_OS_16 = 5
|
|
BMP280_PRES_OS_SKIP = 0
|
|
BMP280_PRES_OS_1 = 1
|
|
BMP280_PRES_OS_2 = 2
|
|
BMP280_PRES_OS_4 = 3
|
|
BMP280_PRES_OS_8 = 4
|
|
BMP280_PRES_OS_16 = 5
|
|
# BMP280 Temperature Registers
|
|
BMP280_REGISTER_DIG_T1 = 0x88
|
|
BMP280_REGISTER_DIG_T2 = 0x8A
|
|
BMP280_REGISTER_DIG_T3 = 0x8C
|
|
# BMP280 Pressure Registers
|
|
BMP280_REGISTER_DIG_P1 = 0x8E
|
|
BMP280_REGISTER_DIG_P2 = 0x90
|
|
BMP280_REGISTER_DIG_P3 = 0x92
|
|
BMP280_REGISTER_DIG_P4 = 0x94
|
|
BMP280_REGISTER_DIG_P5 = 0x96
|
|
BMP280_REGISTER_DIG_P6 = 0x98
|
|
BMP280_REGISTER_DIG_P7 = 0x9A
|
|
BMP280_REGISTER_DIG_P8 = 0x9C
|
|
BMP280_REGISTER_DIG_P9 = 0x9E
|
|
BMP280_REGISTER_ID = 0xD0
|
|
BMP280_REGISTER_RESET = 0xE0
|
|
BMP280_REGISTER_STATUS = 0xF3
|
|
BMP280_REGISTER_CONTROL = 0xF4
|
|
BMP280_REGISTER_CONFIG = 0xF5 # IIR filter config
|
|
BMP280_REGISTER_DATA = 0xF7
|
|
|
|
class BMP280:
|
|
def __init__(self, i2c_bus, addr=0x77):
|
|
self._bmp_i2c = i2c_bus
|
|
self._i2c_addr = addr
|
|
self.chip_id = self._read(BMP280_REGISTER_ID, 2)
|
|
|
|
self._T1 = unp('<H', self._read(BMP280_REGISTER_DIG_T1, 2))[0]
|
|
self._T2 = unp('<h', self._read(BMP280_REGISTER_DIG_T2, 2))[0]
|
|
self._T3 = unp('<h', self._read(BMP280_REGISTER_DIG_T3, 2))[0]
|
|
self._P1 = unp('<H', self._read(BMP280_REGISTER_DIG_P1, 2))[0]
|
|
self._P2 = unp('<h', self._read(BMP280_REGISTER_DIG_P2, 2))[0]
|
|
self._P3 = unp('<h', self._read(BMP280_REGISTER_DIG_P3, 2))[0]
|
|
self._P4 = unp('<h', self._read(BMP280_REGISTER_DIG_P4, 2))[0]
|
|
self._P5 = unp('<h', self._read(BMP280_REGISTER_DIG_P5, 2))[0]
|
|
self._P6 = unp('<h', self._read(BMP280_REGISTER_DIG_P6, 2))[0]
|
|
self._P7 = unp('<h', self._read(BMP280_REGISTER_DIG_P7, 2))[0]
|
|
self._P8 = unp('<h', self._read(BMP280_REGISTER_DIG_P8, 2))[0]
|
|
self._P9 = unp('<h', self._read(BMP280_REGISTER_DIG_P9, 2))[0]
|
|
|
|
self._t_os = BMP280_TEMP_OS_2 # temperature oversampling
|
|
self._p_os = BMP280_PRES_OS_16 # pressure oversampling
|
|
# output raw
|
|
self._t_raw = 0
|
|
self._t_fine = 0
|
|
self._t = 0
|
|
self._p_raw = 0
|
|
self._p = 0
|
|
self._read_wait_ms = 100 # interval between forced measure and readout
|
|
self._new_read_ms = 200 # interval between
|
|
self._last_read_ts = 0
|
|
|
|
def _read(self, addr, size=1):
|
|
return self._bmp_i2c.readfrom_mem(self._i2c_addr, addr, size)
|
|
|
|
def _write(self, addr, b_arr):
|
|
if not type(b_arr) is bytearray:
|
|
b_arr = bytearray([b_arr])
|
|
return self._bmp_i2c.writeto_mem(self._i2c_addr, addr, b_arr)
|
|
|
|
def _gauge(self):
|
|
# TODO limit new reads
|
|
now = utime.ticks_ms()
|
|
if utime.ticks_diff(now, self._last_read_ts) > self._new_read_ms:
|
|
self._last_read_ts = now
|
|
r = self._t_os + (self._p_os << 3) + (1 << 6)
|
|
self._write(BMP280_REGISTER_CONTROL, r)
|
|
utime.sleep_ms(100) # TODO calc sleep
|
|
d = self._read(BMP280_REGISTER_DATA, 6) # read all data at once (as by spec)
|
|
self._p_raw = (d[0] << 12) + (d[1] << 4) + (d[2] >> 4)
|
|
self._t_raw = (d[3] << 12) + (d[4] << 4) + (d[5] >> 4)
|
|
self._t_fine = 0
|
|
self._t = 0
|
|
self._p = 0
|
|
|
|
def load_test_calibration(self):
|
|
self._T1 = 27504
|
|
self._T2 = 26435
|
|
self._T3 = -1000
|
|
self._P1 = 36477
|
|
self._P2 = -10685
|
|
self._P3 = 3024
|
|
self._P4 = 2855
|
|
self._P5 = 140
|
|
self._P6 = -7
|
|
self._P7 = 15500
|
|
self._P8 = -14600
|
|
self._P9 = 6000
|
|
|
|
def load_test_data(self):
|
|
self._t_raw = 519888
|
|
self._p_raw = 415148
|
|
|
|
def print_calibration(self):
|
|
print("T1: {} {}".format(self._T1, type(self._T1)))
|
|
print("T2: {} {}".format(self._T2, type(self._T2)))
|
|
print("T3: {} {}".format(self._T3, type(self._T3)))
|
|
print("P1: {} {}".format(self._P1, type(self._P1)))
|
|
print("P2: {} {}".format(self._P2, type(self._P2)))
|
|
print("P3: {} {}".format(self._P3, type(self._P3)))
|
|
print("P4: {} {}".format(self._P4, type(self._P4)))
|
|
print("P5: {} {}".format(self._P5, type(self._P5)))
|
|
print("P6: {} {}".format(self._P6, type(self._P6)))
|
|
print("P7: {} {}".format(self._P7, type(self._P7)))
|
|
print("P8: {} {}".format(self._P8, type(self._P8)))
|
|
print("P9: {} {}".format(self._P9, type(self._P9)))
|
|
|
|
def _calc_t_fine(self):
|
|
# From datasheet page 22
|
|
self._gauge()
|
|
if self._t_fine == 0:
|
|
var1 = (((self._t_raw >> 3) - (self._T1 << 1)) * self._T2) >> 11
|
|
var2 = (((((self._t_raw >> 4) - self._T1) * ((self._t_raw >> 4) - self._T1)) >> 12) * self._T3) >> 14
|
|
self._t_fine = var1 + var2
|
|
|
|
# @property
|
|
def get_BMP_temperature(self):
|
|
self._calc_t_fine()
|
|
if self._t == 0:
|
|
self._t = ((self._t_fine * 5 + 128) >> 8) / 100.
|
|
return self._t
|
|
|
|
# @property
|
|
def get_BMP_pressure(self):
|
|
# From datasheet page 22
|
|
self._calc_t_fine()
|
|
if self._p == 0:
|
|
var1 = self._t_fine - 128000
|
|
var2 = var1 * var1 * self._P6
|
|
var2 = var2 + ((var1 * self._P5) << 17)
|
|
var2 = var2 + (self._P4 << 35)
|
|
var1 = ((var1 * var1 * self._P3) >> 8) + ((var1 * self._P2) << 12)
|
|
var1 = (((1 << 47) + var1) * self._P1) >> 33
|
|
|
|
if var1 == 0:
|
|
return 0
|
|
|
|
p = 1048576 - self._p_raw
|
|
p = int((((p << 31) - var2) * 3125) / var1)
|
|
var1 = (self._P9 * (p >> 13) * (p >> 13)) >> 25
|
|
var2 = (self._P8 * p) >> 19
|
|
|
|
p = ((p + var1 + var2) >> 8) + (self._P7 << 4)
|
|
self._p = p / 256.0
|
|
return self._p
|