UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
1041 of 1269
NXP Semiconductors
UM10503
Chapter 41: LPC43xx I2S interface
41.6.12 I2S Receive Clock Bit Rate register
The bit rate for the I2S receiver is determined by the value of the RXBITRATE register.
The value depends on the audio sample rate, as well as the data size and format used.
The calculation is the same as for TXBITRATE.
41.6.13 I2S Transmit Mode Control register
The Transmit Mode Control register contains additional controls for the transmit clock
source, enabling the 4-pin mode
(SCK and WS signals are shared between I2S transmit and
receive blocks)
, and how MCLK is used.
41.6.14 I2S Receive Mode Control register
The Receive Mode Control register contains additional controls for receive clock source,
enabling the 4-pin mode
(SCK and WS signals are shared between I2S transmit and receive
blocks)
, and how MCLK is used.
Table 909. I2S Receive Clock Rate register (RXBITRATE - address 0x400A 202C (I2S0) and 0x400A 302C (I2S1)) bit
description
Bit
Symbol
Description
Reset
value
5:0
RX_BITRATE
I2S receive bit rate. This value plus one is used to divide RX_MCLK to produce the
receive bit clock.
0
31:6
-
Reserved, user software should not write ones to reserved bits. The value read from a
reserved bit is not defined.
-
Table 910. I2S Transmit Mode Control register (TXMODE - address 0x400A 2030 (I2S0) and 0x400A 3030 (I2S1)) bit
description
Bit
Symbol
Value Description
Reset
value
1:0
TXCLKSEL
Clock source selection for the transmit bit clock divider.
0
0x0
Select the TX fractional rate divider clock output as the source
0x1
Reserved
0x2
Select the RX_MCLK signal as the TX_MCLK clock source
0x3
Reserved
2
TX4PIN
Transmit 4-pin mode selection (SCK and WS signals are shared between I2S transmit
and receive blocks). 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