I am currently working around CMP0 module of the EFM8BB3 chip.
It looks ref. manual misled me:
On EFM8BB3 reference manual (page 152) there's a mistyped register setting entry:
At table 13.2, it stated that, CMXN=1111 for CMP(-) to Vdd connection. (see attached image)
Whereas '1111' disconnects the input as a general "reserved" combination.
After spending two hours, I just put CMXN='1011' for Vdd connection and it worked.
Yes, this is a known mistake for the RM. I saw an internal ticket to address this issue. Hope Silabs could fix it in next revision.
Thanks a lot for pointing out this to out attention.