hi can some one tell me wat does idata in the following line does??
unsigned char idata keypad[4][4]= { '1','2','3','/', '4','5','6','*', '7','8','9','-', 'Z','0','X','+',};
http://www.keil.com/support/man/docs/c51/c51_le_keywords.htm
I suggest that you spend some time familiarising yourself with the specific language extensions provided by C51...
These extensions exist, of course, to cater for the specific features of the 8051 architecture.
If you don't already understand the specific features of the 8051 architecture, then you will also need to spend some time studying the so-called "bible" for the 8051 - links here: www.8052.com/.../120112