Interrupt-Driven Serial I/O Support for printf

This example program shows you how to use the printf library routine with interrupt-driven serial I/O. Interrupt-driven serial routines are included along with a demo program to printf and getchar some stuff. You can also use scanf with these routines. Serial I/O is handled in a separate file (SIO.C) that you can use in your own programs. Works with any 8051. Ring buffers are located in XDATA but it is easy to locate them anywhere.