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Reading signed data from RS232

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VQ on 19 Apr 2011
I want to read 256 signed numbers from RS232. In Hyperterminal I see:
-55 . . . But when I read it in Matlab I saw something like that:
45 53 52 13 13 10 45 . . .
And if I convert "out" to char (val=char(out)) I haven't got 256 numbers, I have 45...I know that this problem is due to conversion into ASCII characters..
Can anybody give me a solution to read correctly the data?

Answers (2)

Chirag Gupta
Chirag Gupta on 19 Apr 2011
Instead of using fread, try using fscanf where you can specify the format.

Ankit Desai
Ankit Desai on 20 Apr 2011
You can provide the precision that you want to use with fread.
The online documentation should provide more details.
  1 Comment
Walter Roberson
Walter Roberson on 20 Apr 2011
Ankit, if you examine char([45 53 52]) you will find it is '-54' so the problem is not the precision the variables are written at, but rather that the data is being ASCII encoded and needs to be converted back to numeric form.

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