STA310 datasheet(17/90 Pages) STMICROELECTRONICS

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STA310

4.4.1.5 Second Input

A second independent input allows to input bitstreams in serial mode.

This second input can be used, to input audio stream from a microphone, while we decode a data stream trough

the main input.

4.4.2 Data parallel interface

Two ways are available to input data in parallel mode:

- Either through the parallel data bus, shared with the external controller,

- Or through the DATAIN register

4.4.2.1 Using the parallel data bus

In this mode the data must be presented on the 8-bit parallel host data bus D[7..0]. Note that this bus is shared

with the external controller. On the rising clock of DSTR the data byte is sampled by the STA310. The signal

REQ is used to signal when the input FIFO is full. When REQ is de-asserted the transfer must be stopped to

avoid data loss.

After the REQ is de-asserted, the decoder is still able to accept data for a limited number of clock cycles.

The maximum number of data that can be transmitted with respect to the change of REQ is given by the follow-

ing formula: Nbits = 23 - 6 * FDSTR/33MHz, where: FDSTR is the DSTR clock frequency, (max is 33 MHz).

The signals DSTR and DCSB are used to make the distinction between Stream Data (strobed by DSTR) and

Control Data (strobed by DCSB). To avoid conflicts, the DSTR signal and the DCSB signal must respect given

timing constraints.

4.4.2.2 Using the DATAIN register

The data can be input by using the control parallel interface as if accessing any other register.

The signal DCSB is therefore used. When using this register to input data stream, there is no need to byte-align

the data.

Figure 8.

LRCLKIN

DSTR

SIN

Transferred data

Discarded data

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