FIX: interpret analog input values as int16 #45
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EL331XSigned representation and absolute value w/MSB sign are the only two representations mentioned in the docs.
EL30XX, EL31XXThis covers bipolar terminals like EL3174, too. Signed, unsigned and absolute w/MSB sign are supported. Ranges specified in docs:
Absolute w/MSB sign seems to only exist to provide a symmetrical range tldr; this is safe to merge after testing :) |
Both signed and unsigned representations behave like a signed 16-bit integer. In the case of unsigned, the value is limited to the range 0-32767, the former is limited to -32768-32767. As such, treating the values from the terminal as int16 (and thus sign extending them when assigning to RVAL) is the correct way of doing things. This does not handle the MSB representation properly however. That will require more work down the line if we ever decide to support it. For now, users will need to use the unsigned or signed representations for the data to be correctly read.
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Closing because I renamed the branch. |
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Both signed and unsigned representations behave like a signed 16-bit integer. In the case of unsigned, the value is limited to the range 0-32767, the former is limited to -32768-32767. As such, treating the values from the device as int16 (and thus sign extending it when assigning to RVAL) is the correct way of doing things.
MSB representation is still not handled in this PR.
Leaving as draft until I can find and test with a bipolar terminal!