PRELIMINARY DATA SHEET
MSP 34x5G
Micronas
21
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 I
2
C 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 00
hex
. 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 FF
hex
, 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.