Audio Control FOUR.1i Specifications download pdf (Page 29)

www.ti.com

TDM DATA TRANSFER

N–1

1N–1N–2

N–2

Right-ChannelData

Left-ChannelData

••••

•••• ••

DSP Mode

Left-JustifiedMode

Offset

Offset Offset

T0153-02

WCLK_x

BCLK_x

DIN_x/

DOUT_x

DIN_x/

DOUT_x

TLV320AIC34

SLAS538A – OCTOBER 2007 – REVISED NOVEMBER 2007

Time-division multiplexed data transfer can be realized in any of the previously mentioned transfer modes if the

256-clock bit clock mode is selected, although it is recommended to be used in either left-justified mode or DSP

mode. By changing the programmable offset, the bit clock in each frame where the data begins can be changed,

and the serial data output driver (DOUT_x) can also be programmed into the high-impedance state during all bit

clocks except when valid data is being put onto the bus. This allows other codecs to be programmed with

different offsets and to drive their data onto the same DOUT_x line, just in a different slot. For incoming data, the

codec simply ignores data on the bus except where it is expected based on the programmed offset. See the

Using TDM Function to Interface Four AIC33 CODECs with a Single Host Processor application report

(SLAA301 ) and the Using TLV320AIC3x Digital Audio Data Serial Interface With Time-Division Multiplexing

Support application report (SLAA311 ).

Note that the location of the data when an offset is programmed is different, depending on what transfer mode is

selected. In DSP mode, both left and right channels of data are transferred immediately adjacent to each other in

the frame. This differs from left-justified mode, where the left- and right-channel data are always a half-frame

apart in each frame. In this case, as the offset is programmed from zero to some higher value, both the left- and

right-channel data move across the frame, but still stay a full half-frame apart from each other. This is depicted in

Figure 24 for the two cases.

Figure 24. DSP Mode and Left-Justified Mode, Showing the

Effect of a Programmed Data Word Offset

Product Folder Link(s): TLV320AIC34

1 2 ... 24 25 26 27 28 29 30 31 32 33 34 ... 97 98

No comments

Audio Control FOUR.1i Specifications Page 29