pressure calibration error

[awherbert]

The pressure calibration gives me incorrect pressures for Raspberrypi I2C. In bmp388.py the calibration parameters are read in byte pieces. Where the parameter is a signed 16bit variable, each of the bytes are treated as though they are separate signed 8bit variables (by calling uint8_int) but the sign bit is only on the most significant byte. Also the last signed 16bit variable is treated as an unsigned 16bit variable. Finally there is a hardwired subtraction of 0.000145 on one of the parameters that I cannot see the need for in the Bosch datasheet. This only affects the Pressure calibration as the temp calibration does not use signed 16bit parameters

[awherbert]

here's a version that works for me (with the alt i2c address) and also writing the osr/odr/iir registers to correspond to drone recommended values - sorry about the ugly code :)

bmp388 - fix.py.txt