Left Shift Overflows

[begeistert]

This issue is related to a bad conversion, when you try to do a left shit of 16-bit, this will lead to an overflow, and the result will be zero, this means that the number is considered an integer, CLanguage should be able to convert this shift to a long value and don't return a zero, this happens in Arduino

byte  pressure_data_high = readRegister(0x1F, 1);
 pressure_data_high &= 0b00000111; //you only needs bits 2 to 0

 //Read the pressure data lower 16 bits:
 unsigned int pressure_data_low = readRegister(0x20, 2);
 //combine the two parts into one 19-bit number:
 long pressure = ((pressure_data_high << 16) | pressure_data_low) / 4;