From what I researched, I need to include <stdio.h> and use printf("hello world") in my application. The IAR project settings must have Library Configuration > Semihosted and Stdout/Stderr > Via Semihosting. The last setting would be Linker > Output > Use Low level I/O emulation modules. But I don't have "Low level I/O emulation modules" check box in Linker > Output ? It only has Output file name: hello_world.out. Is my processor not supported or my j-link not supported ? I know that the printf works and it sends the text to the SDA USB port but that is not what I want. How do I make this Terminal I/O window works with KL25Z ?