MSP3405G Ver la hoja de datos (PDF) - Micronas

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MSP3405G

Multistandard Sound Processor Family

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PRELIMINARY DATA SHEET

MSP 34x5G

3.3.2.1. STANDARD SELECT Register

The TV sound standard of the MSP 34x5G demodula-

tor is determined by the STANDARD SELECT register.

There are two ways to use the STANDARD SELECT

register:

– Setting up the demodulator for a TV sound standard

by sending the corresponding standard code with a

single I2C bus transmission.

– Starting the Automatic Standard Detection for ter-

restrial TV standards. This is the most comfortable

way to set up the demodulator (not for MSP 3435G).

Within 0.5 s the detection and setup of the actual TV

sound standard is performed. The detected stan-

dard can be read out of the STANDARD RESULT

register by the control processor. This feature is rec-

ommended for the primary setup of a TV set. Out-

puts should be muted during Automatic Standard

Detection.

The Standard Codes are listed in Table 3–7.

Selecting a TV sound standard via the STANDARD

SELECT register initializes the demodulator. This

includes: AGC-settings and carrier mute, tuning fre-

quencies, FIR-filter settings, demodulation mode (FM,

AM, NICAM), deemphasis and identification mode.

TV stereo sound standards that are unavailable for a

specific MSP version are processed in analog mono

sound of the standard. In that case, stereo or bilingual

processing will not be possible.

For a complete setup of the TV sound processing from

analog IF input to the source selection, the transmis-

sions as shown in Section 3.5. are necessary.

For reasons of software compatibility to the

MSP 34xxD, a Manual/Compatibility mode is available.

A detailed description of this mode can be found on

page 77.

3.3.2.2. Refresh of STANDARD SELECT Register

A general refresh of the STANDARD SELECT register

is not allowed. However, the following method

enables watching the MSP 34x5G “alive” status and

detection of accidental resets (only versions B6 and

later):

– After Power-on, bit[15] of CONTROL will be set; it

must be read once to enable the reset-detection

feature.

– Reading of the CONTROL register and checking

the reset indicator bit[15] .

– If bit[15] is “0”, any refresh of the STANDARD

SELECT register is not allowed.

– If bit[15] is “1”, indicating a reset, a refresh of the

STANDARD SELECT register and all other MSPG

registers is required.

3.3.2.3. STANDARD RESULT Register

If Automatic Standard Detection is selected in the

STANDARD SELECT register, status and result of the

Automatic Standard Detection process can be read out

of the STANDARD RESULT register. The possible

results are based on the mentioned Standard Code

and are listed in Table 3–8.

In cases where no sound standard has been detected

(no standard present, too much noise, strong interfer-

ers, etc.) the STANDARD RESULT register contains

00 00hex. In that case, the controller has to start further

actions (for example set the standard according to a

preference list or by manual input).

As long as the STANDARD RESULT register contains

a value greater than 07 FFhex, the Automatic Standard

Detection is still active. During this period, the MODUS

and STANDARD SELECT register must not be written.

The STATUS register will be updated when the Auto-

matic Standard Detection has finished.

If a present sound standard is unavailable for a specific

MSP-version, it detects and switches to the analog

mono sound of this standard.

Example:

The MSPs 3425G and 3445G will detect a B/G-NICAM

signal as standard 3 and will switch to the analog FM-

Mono sound.

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