Hello @D_pengF,
According to the KEA128 Sub-Family Reference Manual the KBI assignment is as follows:
[Excerpt of Table 3-45. KBI port assignment]
Now, let's check the line of your code:
Remember that 0x10 means 0001 0000b which would indeed enable the CH4 (PTE4) as follows:
[Section 35.4.1 KBI Pin Enable Register (KBIx_PE)]
You might find useful to take a look at the following information to help you with your development of KBI and KEA128:
Warm regards, Raul.