EFM32WG Datasheet, PDF (450/834 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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Table 17.7. USART Baud Rates @ 4MHz Peripheral Clock
Desired
baud rate
[baud/s]
USARTn_OVS =00
USARTn_CLKDIV/256
Actual baud
rate [baud/s]
600
415,75
599,88
1200
207,25
1200,48
2400
103,25
2398,082
4800
51
4807,692
9600
25
9615,385
14400
16,25
14492,75
19200
12
19230,77
28800
7,75
28571,43
38400
5,5
38461,54
57600
3,25
58823,53
76800
2,25
76923,08
115200
1,25
111111,1
230400
0
250000
USARTn_OVS =01
Error %
USARTn_CLKDIV/256
Actual baud
rate [baud/s]
-0,02
832,25
600,06
0,04
415,75
1199,76
-0,08
207,25
2400,96
0,16
103,25
4796,163
0,16
51
9615,385
0,64
33,75
14388,49
0,16
25
19230,77
-0,79
16,25
28985,51
0,16
12
38461,54
2,12
7,75
57142,86
0,16
5,5
76923,08
-3,55
3,25
117647,1
8,51
1,25
222222,2
Error %
0,01
-0,02
0,04
-0,08
0,16
-0,08
0,16
0,64
0,16
-0,79
0,16
2,12
-3,55
17.3.2.3 Data Transmission
Asynchronous data transmission is initiated by writing data to the transmit buffer using one of the
methods described in Section 17.3.2.3.1 (p. 450) . When the transmission shift register is empty and
ready for new data, a frame from the transmit buffer is loaded into the shift register, and if the transmitter
is enabled, transmission begins. When the frame has been transmitted, a new frame is loaded into the
shift register if available, and transmission continues. If the transmit buffer is empty, the transmitter goes
to an idle state, waiting for a new frame to become available.
Transmission is enabled through the command register USARTn_CMD by setting TXEN, and disabled
by setting TXDIS in the same command register. When the transmitter is disabled using TXDIS, any
ongoing transmission is aborted, and any frame currently being transmitted is discarded. When disabled,
the TX output goes to an idle state, which by default is a high value. Whether or not the transmitter is
enabled at a given time can be read from TXENS in USARTn_STATUS.
When the USART transmitter is enabled and there is no data in the transmit shift register or transmit
buffer, the TXC flag in USARTn_STATUS and the TXC interrupt flag in USARTn_IF are set, signaling
that the transmitter is idle. The TXC status flag is cleared when a new frame becomes available for
transmission, but the TXC interrupt flag must be cleared by software.
17.3.2.3.1 Transmit Buffer Operation
The transmit-buffer is a 2-level FIFO buffer. A frame can be loaded into the buffer by writing
to USARTn_TXDATA, USARTn_TXDATAX, USARTn_TXDOUBLE or USARTn_TXDOUBLEX. Using
USARTn_TXDATA allows 8 bits to be written to the buffer, while using USARTn_TXDOUBLE will write
2 frames of 8 bits to the buffer. If 9-bit frames are used, the 9th bit of the frames will in these cases be
set to the value of BIT8DV in USARTn_CTRL.
To set the 9th bit directly and/or use transmission control, USARTn_TXDATAX and
USARTn_TXDOUBLEX must be used. USARTn_TXDATAX allows 9 data bits to be written, as well
as a set of control bits regarding the transmission of the written frame. Every frame in the buffer is
stored with 9 data bits and additional transmission control bits. USARTn_TXDOUBLEX allows two
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