[flashrom] Nec/Renesas 78k0s flash programming?

[Riccardo Delpopolo Carciopolo]

Hi,
I've used flashrom with pickit2 in past.
I'm a newbie but I'd like to add support for this MCUs by myself.
On Internet exist some parallel programmer but I want to program a 78k0s
flash my with the uart protocol.
We're can I start from?
It requires some vpp pulses to enable the uart programming mode.

Thabk you for help