EFM32WG Datasheet, PDF (454/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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locations 8, 9 and 10 in the figure, locations 4, 5 and 6 for OVS=1 and locations 3, 4, and 5 for OVS=2.
The value of a sampled bit is determined by majority vote. If two or more of the three bit-samples are
high, the resulting bit value is high. If the majority is low, the resulting bit value is low.
Majority vote is used for all oversampling modes except 4x oversampling. In this mode, a single sample
is taken at position 3 as shown in Figure 17.5 (p. 454) .
Majority vote can be disabled by setting MVDIS in USARTn_CTRL.
If the value of the start bit is found to be high, the reception of the frame is aborted, filtering out false
start bits possibly generated by noise on the input.
Figure 17.5. USART Sampling of Start and Data Bits
Idle
St art bit
Bit 0
0 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11 12 13
0
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
0
1
2
3
4
5
6
1
2
3
4
5
1
2
3
4
1
2
3
4
If the baud rate of the transmitter and receiver differ, the location each bit is sampled will be shifted
towards the previous or next bit in the frame. This is acceptable for small errors in the baud rate, but for
larger errors, it will result in transmission errors.
When the number of stop bits is 1 or more, stop bits are sampled like the start and data bits as seen in
Figure 17.6 (p. 454) . When a stop bit has been detected by sampling at positions 8, 9 and 10 for normal
mode, or 4, 5 and 6 for smart mode, the USART is ready for a new start bit. As seen in Figure 17.6 (p.
454) , a stop-bit of length 1 normally ends at c, but the next frame will be received correctly as long as
the start-bit comes after position a for OVS=0 and OVS=3, and b for OVS=1 and OVS=2.
Figure 17.6. USART Sampling of Stop Bits when Number of Stop Bits are 1 or More
n’th bit
1 stop bit
a
b
c
Idle or start bit
13 14 15 16 1 2 3 4 5 6 7 8 9 10 0/1 X X X X X
7
8
1
2
3
4
5
6 0/1 X
6
1
2
3
4
5
0/1
1
4
1
2
3
0/1
1
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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