TC65 Hardware Interface Description
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TC65_HD_V00.521
Page 59 of 99
24.05.2005
3.13.4 Digital Audio Interface DAI
The DAI can be used to connect audio devices capable of PCM (Pulse Code Modulation), for
example a codec.
Table 10: Overview of DAI pin functions
Signal name on
B2B connector
Function for PCM Interface
Input/Output
DAI0 TXDAI
O
DAI1 RXDAI
I
DAI2
FS (Frame sync)
O
DAI3 BITCLK
O
DAI4 nc
I
DAI5 nc
I
DAI6 nc
I
To clock input and output PCM samples the PCM interface delivers a bit clock (BITCLK)
which is synchronous to the GSM system clock. The frequency of the bit clock is 128±1kHz.
The frame sync signal (FS) has a frequency of 8kHz and is high for one BITCLK period. The
PCM interface is master for the bit clock and the frame sync signals.
BITCLK
FS
TXDAI
RXDAI
bitclk
frame sync
TX_data
RX_data
Codec
PCM interface of
the GSM module
Figure 23: PCM interface application