I can't seem to get printf going on my system. I've declared putchar as extern and written a routine called putchar to output to the serial port, but the application dies whenever I try to printf. I dare say I'm not doing something fairly fundamental!
There is a generic GNU example that shows printf I/O in the folder: Keil\ARM\GNU\Examples\Hello. It is written for a Atmel device, but can be easily adapted to any other part. Change the following: