cx25840 Conexant Systems, Inc., cx25840 Datasheet - Page 116

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

Detailed Functional Description
3-90
To program audio core for forced FM Radio and auto-mode detection, program the
following registers:
Refer to the Audio Configuration register for other standard and mode combination
setting.
1.
2.
3.
4.
1.
2.
3.
4.
5.
6.
Set PREF_MODE in Preferred Decode Mode (0x809) register to:
a.
b.
c.
Set MUTE_NO_PREF_MODE in Preferred Decode Mode (0x809) register to:
a.
b.
Set AUD_STANDARD in Audio Configuration (0x808) register to 0xF
Set AUD_SYSTEM in Audio Configuration (0x808) register to 0x8
Set TUNER_OUTPUT_FORMAT in Audio Format Control (0x80B) register to:
a.
b.
Set DE_EMPHASIS_TIME in Preferred Decode Mode (0x809) mode to:
a.
b.
Set PREF_MODE in Preferred Decode Mode (0x809) mode to:
a.
b.
Set MUTE_NO_PREF_MODE in Audio Format Control (0x80B) register to:
a.
b.
Set AUD_STANDARD in Audio Configuration (0x808) register to 0xF
Set AUD_SYSTEM in Audio Configuration (0x808) register to 0x9
0x0-0x3—for Mono1 (Language A or Mono), Mono2 (Language B), Mono3
(Language C), Mono4 (Analog Fallback)
0x4—for Stereo
0x5–0x7—for Dual1 (AC), Dual2 (BC), Dual3 (AB)
0x0—the microcontroller selects the best audio program based on the
preferred mode (i.e., if the preferred mode is language B and stereo is the
detected mode, stereo will be played).
0x1—the microcontroller will mute the audio if the preferred mode is not
available (i.e., if the preferred mode is language B and stereo is the detected
mode, audio will be muted.
0x0—if signal is a modulated 2nd IF signal
0x1—if signal is an unmodulated AF signal
0x0—for 75
0x1—for 50
0x0—for Mono
0x4—for Stereo
0x0—the microcontroller selects the best audio program based on the
preferred mode (i.e., if the preferred mode is language B and stereo is the
detected mode, stereo will be played).
0x1—the microcontroller will mute the audio if the preferred mode is not
available (i.e., if the preferred mode is language B and stereo is the detected
mode, audio will be muted.Set AUD_STANDARD in Audio Configuration
(0x808) register to 0xF
µ
µ
s pre-emphasis
s pre-emphasis
Conexant
CX25840/1/2/3 Data Sheet
102284B
8/3/05