I wonder if someone can help me out. I would like to send serial data by modifying the 'simple_coap_server' main program. I added the following header 'app_uart.h' to make use of the functions but when I compile the program using GCC ('make' command in Windows), I get No such file or directory #include "app_uart.h". What I don't understand is that the file is in the directory and that I can compile the 'UART' example using GCC successfully without any problems. Any thoughts please, maybe I'm missing something?