Reading signed data from RS232

Hi,

I want to read 256 signed numbers from RS232. In Hyperterminal I see:

-54

-54

-54

-52

-55 . . . But when I read it in Matlab I saw something like that:

out=fread(s)

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?

Answer 1

[Chirag Gupta]

Instead of using fread, try using fscanf where you can specify the format.

http://www.mathworks.com/access/helpdesk/help/techdoc/ref/serial.fscanf.html

Answer 2

[Ankit Desai]

You can provide the precision that you want to use with fread.

The online documentation should provide more details.

-Ankit

[Walter Roberson]

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.