cx25840 Conexant Systems, Inc., cx25840 Datasheet - Page 134

• Manufacturer Part Number: cx25840
• Description: Video Decoder And Broadcast Audio
• Manufacturer: Conexant Systems, Inc.

Detailed Functional Description
3.26
3-108
Quick Start Audio
To configure the audio decoder for demodulation of any the audio standards, only a
few registers must be programmed. For maximum flexibility, the level of auto-
detection and number of systems searched for can be specified. For best performance,
however, it is recommended that users specify the minimum number of systems that
they will encounter.
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To program embedded microcontroller for automatic pan-Europe TV audio
standard and mode detection (systems BG, DK, I, and L), program the following
registers:
To program embedded microcontroller for automatic NICAM-BG and A2-BG TV
audio standard and mode detection (system-BG), program the following registers:
To program embedded microcontroller for automatic North-American TV audio
standard and mode detection (system BTSC), program the following registers:
To program embedded microcontroller for automatic EIAJ TV audio standard and
mode detection (system EIAJ), program the following registers:
To program embedded microcontroller for automatic European AF FM Radio
mode detection, program the following registers:
Set FORMAT_65MHZ in the Audio Format Control (0x80B) register to 0x2 so
the 6.5 MHz carrier is auto-detected for either AM or FM.
Set FORMAT_45MHZ in the Audio Format Control (0x80B) register to 0x0 so
the 4.5 MHz carrier is interpreted as Chroma (default).
Set FM_DEVIATION in the Preferred Decode Mode (0x809) register to 0x0 for
normal FM (default).
Set AUD_STANDARD in the Audio Configuration (0x808) register to 0xF
Set AUD_SYSTEM in the Audio Configuration (0x808) register to 0xF.
PREF_MODE and MUTE_NO_PREF_MODE in the Preferred Decode Mode
(0x809) register must be taken as inputs from the user and written to this register.
Set AUD_STANDARD in the Audio Configuration (0x808) register to 0xF.
Set AUD_SYSTEM in the Audio Configuration (0x808) register to 0x0.
PREF_MODE and MUTE_NO_PREF_MODE in the Preferred Decode Mode
(0x809) register must be taken as inputs from the user and written to this register.
Set AUD_STANDARD in Audio Configuration (0x808) register to 0xF.
Set AUD_SYSTEM in Audio Configuration (0x808) register to 0x6.
PREF_MODE and MUTE_NO_PREF_MODE in the Preferred Decode Mode
(0x809) register must be taken as inputs from the user and written to this register.
Set AUD_STANDARD in the Audio Configuration (0x808) register to 0xF.
Set AUD_SYSTEM in the Audio Configuration (0x808) register.
PREF_MODE and MUTE_NO_PREF_MODE in the Preferred Decode Mode
(0x809) register must be taken as inputs from the user and written to this register.
Set TUNER_OUTPUT_FORMAT in the Audio Format Control (0x80B) register
to 0x1.
Set DE_EMPHASIS_TIME in the Preferred Decode Mode (0x809) register to
0x1.
Set AUD_STANDARD in the Audio Configuration (0x808) register to 0xF.
Set AUD_SYSTEM in the Audio Configuration (0x808) register to 0x9.
PREF_MODE and MUTE_NO_PREF_MODE in the Preferred Decode Mode
(0x809) register must be taken as inputs from the user and written to this register.
Conexant
CX25840/1/2/3 Data Sheet
102284B
8/3/05