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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
455 of 808
NXP Semiconductors
UM10360
Chapter 20: LPC17xx I2S interface
5.14 Receive Mode Control register (I2SRXMODE - 0x400A 8034)
The Receive Mode Control register contains additional controls for receive clock source,
enabling the 4-pin mode, and how MCLK is used. See
for a summary of
useful mode combinations.
6.
I
2
S transmit and receive interfaces
The I
2
S interface can transmit and receive 8-bit, 16-bit or 32-bit stereo or mono audio
information. Some details of I
2
S implementation are:
•
When the FIFO is empty, the transmit channel will repeat transmitting the same data
until new data is written to the FIFO.
•
When mute is true, the data value 0 is transmitted.
•
When mono is false, two successive data words are respectively left and right data.
Table 398: Transmit Mode Control register (I2STXMODE - 0x400A 8030) bit description
Bit
Symbol
Value Description
Reset
Value
1:0
TXCLKSEL
Clock source selection for the transmit bit clock divider.
0
00
Select the TX fractional rate divider clock output as the
source
01
Reserved
10
Select the RX_MCLK signal as the TX_MCLK clock source
11
Reserved
2
TX4PIN
Transmit 4-pin mode selection. When 1, enables 4-pin
mode.
0
3
TXMCENA
Enable for the TX_MCLK output. When 0, output of
TX_MCLK is not enabled. When 1, output of TX_MCLK is
enabled.
0
31:4
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
Table 399: Receive Mode Control register (I2SRXMODE - 0x400A 8034) bit description
Bit
Symbol
Value Description
Reset
Value
1:0
RXCLKSEL
Clock source selection for the receive bit clock divider.
0
00
Select the RX fractional rate divider clock output as the
source
01
Reserved
10
Select the TX_MCLK signal as the RX_MCLK clock source
11
Reserved
2
RX4PIN
Receive 4-pin mode selection. When 1, enables 4-pin
mode.
0
3
RXMCENA
Enable for the RX_MCLK output. When 0, output of
RX_MCLK is not enabled. When 1, output of RX_MCLK is
enabled.
0
31:4
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA