Siemens TC65 Specifications download pdf (Page 69)

TC65 Hardware Interface Description

Confidential / Released

TC65_HD_V02.000 Page 69 of 120 08.06.2006

3.15.4 Digital Audio Interface DAI

The DAI can be used to connect audio devices capable of PCM (Pulse Code Modulation), for

example a codec.

Table 15: 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 256 kHz.

Any edge of this clock deviates less than ±100ns (Jitter) from an ideal 256-kHz clock. The

frame sync signal (FS) has a frequency of 8kHz and is high for one BITCLK period. Each

frame has a duration of 125 µs and contains 32 clock cycles. The PCM interface is master

for the bit clock and the frame sync signals.

BITCLK

TXDAI

RXDAI

bitclk

frame sync

TX_data

RX_data

Codec

PCM interface of

the GSM module

Figure 28: PCM interface application

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Siemens TC65 Specifications Page 69