I am trying to work with the FXPS7550 from a Raspberry Pi and it does not make any sense.
Note that I have connected other I2C devices to this machine before, without any issues.
Is there any example code for communicating with the sensor available?
The datasheet, sadly, raises more questions than it explains things. For example:
- In section 7.3.4.2, for the temperature calculation "T_LSB" is mentioned. What is this? The value read from 0Eh, or the value read from SNSDATA0 when DATATYPE0 is set to 1?
- Why is the temperature register value ranging from 13 to 250 on consequent reads? Shouldn’t the temperature stay relatively constant when the sensor is running in air?
- What is the difference between SNSDATA0 and SNSDATA1? The datasheet just states that both registers contain pressure data, but what is the difference?
- Where do the values come from / what do the variables mean in equation (4)? Is PABS_LSB the data read from the pressure register? If so, is it from SNSDATA0 or SNSDATA1? With both I get around 300kPa pressure, which does not seem right when the sensor is running in air.
- Shouldn’t the pressure calibration value in register 0x4C, 0x4D be constant? When I read from it I get a different value every time.
