Conversion of ascii and hex

I hav hex data that to be sent through rs232 as ascii. In the same way, received ascii data in rs232 has to be converted into hex. But in matlab,no hex to ascii and ascii to hex conversion is available. Pls help me to do so......

Answer 1

[Mark Shore]

dec2hex(uint8('a'))

char(hex2dec('61'))

Also consult the documentation on character arrays.

Answer 2

[Jan]

Much faster than HEX2DEC:

sscanf('61', '%x')      % 97
sscanf('abcd', '%x')    % 43981
sscanf('abcd', '%2x')   % [171;205]

And if you recieve the values from the serial port, FSCANF can convert from HEX directly.

EDITED: (Consider Walter's and my comments) For a direct conversion of the ASCII character to a HEX number and backwards:

sprintf('%x', 'M');        % '4d'
char(sscanf('%x', '4d'));  % 'M'

Works with FPRINTF directly also.

[Mark Shore]

It may be faster, but the OP was likely looking for specific ascii to hex conversion as per the ascii standard where, for example, 'M' = 4D and 'm' = 6D. http://www.asciitable.com/

As well, it's not clear to me how you would reverse the operation using this method.

[Jan]

@Mark: What about this:

sprintf('%x', double('M')) % '4d'

sprintf('%x', double('m')) % '6d'

And the other way around:

char(sscanf('4d', '%x')) % 'm'

Or if you want upper case with '%X'.

[Walter Roberson]

You don't even need the double()

sprintf('%x','M')

[Mark Shore]

Those work nicely. For longer ascii strings you'd have to break up the multicharacter hex string into two character increments to go back to ascii, but that shouldn't be much of a problem.

It's a little odd that there's no direct conversion available and that all of the suggestions so far have been workarounds.

[Walter Roberson]

Mark, a minor variation on my earlier solution solves the break-up issue:

char(sscanf(String,'%2X').')

The original poster has not been back to clarify what they were looking for, so I would hesitate to say the suggestions are "workarounds".

Answer 3

[Titus Edelhofer]

Hi,

what about dec2hex and hex2dec/hex2num?

Titus

Answer 4

[Walter Roberson]

How is your hex data represented? If it is a vector of numbers each of which has an integer value 0 to 15, then

fprintf(s,'%X', YourVector)

and you would read it with

fscanf(s,'%1X')

Or, more likely,

sscanf(fgetl(s),'%1X')

[Walter Roberson]

If you are working with a string that is an even number of bytes, you could use

char(hex2dec(reshape(String,2,[]).').')

I would expect, though, that char(sscanf(String,'%2X').') would be faster.