STA015$ STMicroelectronics, STA015$ Datasheet - Page 11

• Manufacturer Part Number: STA015$
• Description: DECODER AUDIO MPEG 2.5 28-SOIC
• Manufacturer: STMicroelectronics
• Type: Audio Decoderr

Specifications of STA015$

• Applications: Sound Cards, Players, Recorders
• Voltage - Supply, Digital: 2.4 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply, Analog: -
• Lead Free Status / Rohs Status: Compliant

proper operation BIT_EN line should be toggled only when SCKR is stable low (for both SCLK_POL con-
figuration). The possible configurations are described in Fig. 8.
3.2 GPSO Output Interface
In order to retrieve ADPCM encoded data a General Purpose Serial Output interface is available (in
TQFP44 and LFBGA64 packages only). The maximum frequency for GPSO_SCKR clock is the DSP sys-
tem clock frequency divided by 3 (i.e. 8.192 MHz @ 24.58MHz). The interface is based on a simple and
configurable 3-lines protocol, as described by figure 10.
3.3 PCM Output Interface
The decoded audio data are output in serial PCM format. The interface consists of the following signals:
SDO
SCKT
LRCLK
The output samples precision is selectable from 16 to 24 bits/word, by setting the output precision with
PCMCONF (16, 18, 20 and 24 bits mode) register. Data can be output either with the most significant bit
first (MS) or least significant bit first LS), selected by writing into a flag of the PCMCONF register.
Figure 9 gives a description of the several STA015 PCM Output Formats. The sample rates set decoded
by STA015 is described in Table 1.
To enable the GPSO interface bit GEN of GPSO_ENABLE register must be set. Using the GPSO_CONF
register the protocol can be configured in order to provide outcoming data on rising/ falling edge of
GPSO_SCKR input clock; the GPSO_REQ request signal polarity (usually connected to an MCU interrupt
line) can be configured as well.
Figure 9. PCM Output Formats
Table 1. MPEG Sampling Rates (KHz)
MPEG 1
44.1
48
32
PCM Serial Data Output
PCM Serial Clock Output
Left/Right Channel Selection Clock
MPEG 2
22.05
24
16
MPEG 2.5
11.025
12
8
STA015
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