int16 to uint8 array conversion for Serial Transmit

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phil on 26 May 2017
Answered: phil on 26 May 2017
Hello there, I would like to take a int16 and split it into a uint8 array to transmit via serial connection (arduino).
Then i would like to reassemble the the two bytes to give me back my original int16. Any help would be appreciated :)

Answers (3)

Guillaume on 26 May 2017
Edited: Guillaume on 26 May 2017
exampleint16 = int16(12345);
sameasuint8 = typecast(exampleint16, 'uint8')
restoredint16 = typecast(sameasuint8, 'int16')
However, if all you want to do is transmit that int16. You could just fwrite it as is, and read it as an uint8:
%on the sender
fwrite(serialobj, yourint16, 'int16')
%on the reader
fread(serialobj, 2, 'uint8')
  1 Comment
Walter Roberson
Walter Roberson on 26 May 2017
If you fwrite() the int16 then be sure to check the serial ByteOrder property.
If you split into uint8 using typecast() then you need to take care of the endian problems yourself. For this purpose you need to know that if you typecast a 16 bit quantity into uint8 then on all current implementations of MATLAB, the first byte of the result is the least significant byte.

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phil on 26 May 2017
Edited: phil on 26 May 2017
Your answer works fine in Matlab however in simulink i get port dimension errors. This is probably due to the fact that i could be varying size? any ideas how to cope?\

phil on 26 May 2017
Ok a little bit more resarch has turned out specifying data size in the model explorer works: :)

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