UART I/O and Memory Allocation Example for GNU The project GNU_IODemo shows how to use memory allocation routines (malloc) and char I/O (printf, scanf) via a serial interface with the GNU toolchain. The I/O functions are adapted for the Analog Devices ADuC7000 series using the SERIAL.C module. The example also shows the efficiency of the Keil CA ARM Compiler run-time library which is tuned for single chip systems.