EFM32WG Datasheet, PDF (466/834 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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create an appropriate format. MONO enables mono mode, i.e. one data stream instead of two which is
the default. JUSTIFY aligns data within a word on the I2S bus, either left or right which can bee seen in
figures Figure 17.20 (p. 467) and Figure 17.21 (p. 467). Finally, DELAY specifies whether a new I2S
word should be started directly on the edge of the word-select signal, or one bit-period after the edge.
Table 17.9. USART I2S Modes
Mode
Regular I2S
Left-Justified
Right-Justified
Mono
MONO
0
0
0
1
JUSTIFY
0
0
1
0
DELAY
1
0
0
0
CLKPOL
0
1
1
0
The regular I2S waveform is shown in Figure 17.18 (p. 466) and Figure 17.19 (p. 466) . The first
figure shows a waveform transmitted with full accuracy. The wordlength can be configured to 32-bit,
16-bit or 8-bit using FORMAT in USARTn_I2SCTRL. In the second figure, I2S data is transmitted with
reduced accuracy, i.e. the data transmitted has less bits than what is possible in the bus format.
Note that the msb of a word transmitted in regular I2S mode is delayed by one cycle with respect to
word select
Figure 17.18. USART Standard I2S waveform
USn _CLK
USn _CS
(word select)
USn _TX/
USn _RX
LSB MSB
Right channel
Left channel
LSB MSB
Right channel
Figure 17.19. USART Standard I2S waveform (reduced accuracy)
USn _CLK
USn _CS
(word select)
USn _TX/
MSB
USn _RX
Right channel
LSB
Left channel
MSB
Right channel
A left-justified stream is shown in Figure 17.20 (p. 467) . Note that the MSB comes directly after the
edge on the word-select signal in contradiction to the regular I2S waveform where it comes one bit-
period after.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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