EFM8BB2 Datasheet, PDF (30/55 Pages) Silicon Laboratories – The EFM8BB2 highlighted features are listed below

6. Pin Definitions
6.1 EFM8BB2x-QFN28 Pin Definitions
EFM8BB2 Data Sheet
Pin Definitions
P0.1 ¹
P0.0 2
GND 3
N/C 4
N/C 5
VDD 6
VREGIN 7
28 pin QFN
(Top View)
GND
21 _P1.1
20 P1.2
19 P1.3
18 P1.4
17 P1.5
16 P1.6
15 P1.7
Figure 6.1. EFM8BB2x-QFN28 Pinout
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