I2S Registers
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SWRU543–January 2019
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Inter-Integrated Sound (I2S) Multichannel Audio Serial Port
12.5.2 WFIFOCTL Register (Offset = 10h) [reset = 1004h]
WFIFOCTL is shown in Figure 12-5 and described in Table 12-7.
Return to Summary Table.
The WNUMEVT and WNUMDMA values must be set before enabling the Write FIFO. If the Write FIFO is
to be enabled, it must be enabled before taking the I2S out of reset.
Figure 12-5. WFIFOCTL Register
31 30 29 28 27 26 25 24
RESERVED
R-0h
23 22 21 20 19 18 17 16
RESERVED WENA
R-0h R/W-0h
15 14 13 12 11 10 9 8
WNUMEVT
R/W-10h
7 6 5 4 3 2 1 0
WNUMDMA
R/W-4h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 12-7. WFIFOCTL Register Field Descriptions
Bit Field Type Reset Description
31-17 RESERVED R 0h
Reserved. The reserved bit location always returns the default value.
A value written to this field has no effect. If writing to this field,
always write the default value for future device compatibility.
16 WENA R/W 0h
Write FIFO enable bit.
0h = Write FIFO is disabled. The WLVL bit in the Write FIFO status
register (WFIFOSTS) is reset to 0 and pointers are initialized, that is,
the Write FIFO is “flushed.”
1h = Write FIFO is enabled. If Write FIFO is to be enabled, it must
be enabled before taking I2S out of reset.
15-8 WNUMEVT R/W 10h
Write word count per DMA event (32-bit). When the Write FIFO has
space for at least WNUMEVT words of data, then an AXEVT
(transmit DMA event) is generated to the host/DMA controller. This
value should be set to a nonzero integer multiple of the number of
serializers enabled as transmitters. This value must be set before
enabling the Write FIFO.
0h = 0 words
1h = 1 word
2h = 2 words
3h - 40h = 3 to 16 words
41h - FFh = Reserved
7-0 WNUMDMA R/W 4h
Write word count per transfer (32-bit words). Upon a transmit DMA
event from the McASP, WNUMDMA words are transferred from the
Write FIFO to the I2S. This value must equal the number of McASP
serializers used as transmitters. This value must be set before
enabling the Write FIFO.
0h = 0 words
1h = 1 word
2h = 2 words
3h - 10h = 3 to 16 words
11h - FFh = Reserved
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