UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
1049 of 1269
NXP Semiconductors
UM10503
Chapter 41: LPC43xx I2S interface
41.7.2.1.5
4-Wire Transmitter mode
Table 916.
4-Wire Transmitter mode
CREG bit 12 DAO bit 5 TXMODE
bits [3:0]
Description
x
0
0 0 x x
4-wire transmitter mode sharing the receiver RX_SCK and RX_WS (4-pin mode).
The I2S transmit function operates as an internal slave to the receive function.
The receive function can operate in either master or slave mode, determining the
operating mode of the entire I2S interface.
The transmit clock source is RX_SCK.
The WS used is the internally generated RX_WS.
The TX_MCLK pin is not enabled for output.
Bold lines indicate the clock path for this configuration.
Fig 139.
4-Wire Transmitter mode
I
2
S
peripheral
block
I2STXMODE[1:0]=XX
I2STXMODE[2]=1
0
1
TX_SCK
RX_SCK
(1 to 64)
TX_MCLK
10
00
8-bit
Fractional
Rate Divider
X
Y
I2STX_RATE[15:8]
I2STX_RATE[7:0]
1
0
I2STXBITRATE[5:0]
RX_MCLK
0
1
TX_WS
RX_WS
I2SDAO[5]=1
Pin OEn
I2S_TX_WS
I2S_TX_SDA
I2S_TX_MCLK
I2STXMODE[3]=0
Pin OE
I2S_TX_SCK
01
I2SDAO[5]=1
0
1
CREG6[12]=X
0
1
PLLAUDIO
I2STXMODE[2]=0
PCLK