RGB LED Lighting Shield with XMC1202 - XMC source code

Hello, I have one question regarding the shield: Does anyone know why it is not possible to set WALKTIME lower than 15?


This code:

I2CWRITE2BYTES (ADDRESS, WALKTIME, 25);

works fine, while this code:

I2CWRITE2BYTES (ADDRESS, WALKTIME, 5)

sets the walktime to 15.

Is there any chance to switch of walktime entirely?

Thanks a lot!