just bought TI stellaris DEV board and saw two MCU there, so wondering why two

 

Did u read?

 

I bought a pic dev board and that had three..

The Launch pad has a debugging IC as well as the main micro..

 

why is it needed a separate micro for debugging ,can single mcu will do the debugging ?

 

why is it needed a separate micro for debugging ,can single mcu will do the debugging ?

No place to store debugging code.