MAS3549F datasheet(15/92 Pages) MICRONAS

15 / 92 page

DATA SHEET

MAS 35x9F

Micronas

June 30, 2004; 6251-505-1DS

2.7. Battery Voltage Supervision

Independent of the DC/DC converters, a battery volt-

age supervision circuit (at pin VBAT) is provided. It can

be programmed to supervise one or two battery cells.

The voltage is measured by subsequently setting a

series of voltage thresholds and checking the respec-

tive comparison result in register 77hex.

2.8. Interfaces

The MAS 35x9F uses an I2C control interface, a serial

input interface for MPEG bit streams, and digital audio

output interfaces for the decoded audio data (I2S and

S/PDIF). S/PDIF input is available after Software

download. A parallel I/O interface (PIO) may be used

for fast data exchange.

2.8.1. I2C Control Interface

For controlling and program download purposes, a

standard I2C slave interface is implemented. A

detailed description of all functions can be found in

Section 3.

2.8.2. S/PDIF Input Interface

The S/PDIF interface receives a one-wire serial bus

signal. In addition to the signal input pin SPDI1/SPDI2,

a reference pin SPDIR is provided to support balanced

signal sources or twisted pair transmission lines.

The synchronization time on the input signal is

<50ms.

S/PDIF input is not supported for MPEG 1/2 Layer 2/3

and MPEG 2 AAC.

Micronas has developed a download software for flexi-

ble usage of the S/PDIF I/O and SDI/SDO interfaces. It

is described in Download Software Supplement

I2SPDIF (6251-505-1PDS).

2.8.3. S/PDIF Output

The S/PDIF output of the baseband audio signals is

implemented at pin SPDO since version B4.

The channel status bits can be set as described in

Table 3–8.

2.8.4. Multiline Serial Audio Input (SDI, SDIB)

There are two multiline serial audio input interfaces

(SDI, SDIB) each consisting of the three pins SI(B)C,

SI(B)I, and SI(B)D. The standard firmware only sup-

ports SDIB for bit-stream signals, while PCM-inputs

should be routed to SDI.

The interfaces can be configured as continuous bit-

stream or word-oriented inputs. For the MPEG bit

streams, the word strobe pin SIBI must always be con-

nected to VSS; bits must be sent MSB first as created

by the encoder.

If the download software (refer to Download Software

Supplement I2SPDIF (6251-505-1PDS)) is used, the

interface acts as an I2S-type with SI(B)I as a word-

strobe for PCM data.

For the Demand Mode (see Section 2.5.), the signal

clock coming from the data source must be higher than

the nominal data transmission rate (e.g. 128 kbit/s).

Pin EOD is used to interrupt the data flow whenever

the input buffer of the MAS 35x9F is filled.

For controlling details, please refer to Table 3–8 on

page 32.

2.8.5. Multiline Serial Output (SDO)

The serial audio output interface of the MAS 35x9F is

a standard I2S-like interface consisting of the data

lines SOD, the word strobe SOI and the clock signal

SOC. It is possible to choose between two standard

interface configurations (16-bit data words with word

strobe time offset or 32-bit data words with inverted

SOI signal).

If the serial output generates 32 bits per audio sample,

only the first 20 bits will carry valid audio data. The

12 trailing bits are set to zero by default.

2.8.6. Parallel Input/Output Interface (PIO)

The parallel interface of the MAS 35x9F consists of the

8 data lines PI12...PI19 (MSB) and the control lines

PCS, PR, PRTR, PRTW, and EOD. It can be used for

data exchange with an external memory, for fast pro-

gram download and for other special purposes as

defined by the DSP software.

For MPEG data input, the PIO interface is activated by

setting bits[9] and [8] in D0:346 to 01. For the hand-

shake protocol, please refer to Section 4.6.2.8. on

page 80.

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