ST STM32F301 6 Series Reference Manual page 726

Universal synchronous/asynchronous receiver transmitter (USART/UART)
RX line
Sample clock
RX line
Sample
clock (x8)
726/874
Figure 281. Data sampling when oversampling by 16
1 2 3
Figure 282. Data sampling when oversampling by 8
1 2
Table 100. Noise detection from sampled data
Sampled value
000
001
010
011
100
101
110
111
sampled values
4 5 6 7 8 9
7/16
One bit time
sampled values
3 4 5
3/8
One bit time
NE status
0
1
1
1
1
1
1
0
RM0366 Rev 5
10 11 12 13 14 15
6/16
7/16
6 7
8
2/8
3/8
Received bit value
0
0
0
1
0
1
1
1
RM0366
16
MSv31152V1
MSv31153V1