hai i want to read & write .xml or .txt file ..... i dont know how to do this.....kindly help me.......... thanks in advance
Keil C51 provides no built-in file support - see:
http://www.keil.com/support/man/docs/c51/c51_xa_librarydif.htm
Therefore, if you want file support, you will have to implement it yourself, or incorporate some 3rd-party support.
You would also, of course, need some storage medium capable of holding your files...
Or, as already suggested, leave the file handling to a PC, and just have it send the data over a serial link, or similar...