STV0042/STV0056 APPLICATION NOTE
1 - INTRODUCTION
The purpose of this application note is to provide
the user with the most important informations rele-
vant to the hardware and software environment of
the STV0042 and the STV0056 circuits. In this
introduction part, we would like to mention that the
STV0042/STV0056 circuits features very specific
FM demodulators, consequently we would advice
to pay a specific attention to the relevant chapters.
Conventions
In this note, when the explanations are commun to
both STV0042 and STV0056 circuits : the circuits
are called STV42/56 and when pin numbers are
given, they are relevant to the STV0056 (ex : Pin 15
means Pin 15 of STV0056 (corresponding to
Pin 12 of STV0042)).
When the explanations are relevant to only one
circuit, the entire circuit reference is mentionned
(ex : STV0042). When external components refer-
ence are given in this note, they are relevant to the
STV0056 application circuit (page 31).
When speaking about software :
- R : stands for register - ex : R06 ⇒ Register 06
- B : stands for bit - ex : R06 B1 ⇒ Register 06 Bit1
Other conventions :
- R05 B0-5 ⇒ Register 05 from Bit 0 to Bit 5
- R06 B2 B4 ⇒ Register 05 Bit 2 and Bit 4
- R05 B0-5 = 35 ; it means no attention is paid to
Bit 6 and Bit 7. 35 is the hexadecimal value given
by the 5 first bits.
2 - GENERAL BLOCK DIAGRAMS (differences between STV0042 and STV0056)
The general block diagram of the STV0042 and STV0056 circuits are given in Figure 1 and 2 respectively.
Figure 1 : STV0042 General Block Diagram
From Tuner
From
VCR/Decoder
From Tuner
22kHz to LNB
B-BAND 2
Video
Processing
2
1
FM
Demodulation
2 Channels
Noise
Reduction +
Deemphasis
STV0042
4x2
2
Video
Matrix
Audio
Matrix
2
+
Volume
I2C Bus
Interface
To TV, VCR/Decoder
Active in Stand-by
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