Using a Renesas evaluation board as a Programmer
The Renesas development tools for the RL78 seem to me to be quite complex to use. Unless you have a very compelling need to use the RL78 I would recommend you avoid this 16-bit class controller.
The RL78 architecture is very odd. The code generation can be very inefficient when the code binary grow beyond 64K bytes.
If I recall correctly the RAM address space is a maximum of 64K bytes, and most controllers are have much less actual RAM. The maximum offered for the RL78/G14 is 48K bytes.
You should really consider almost any other controller to learn about.