saa7826 NXP Semiconductors, saa7826 Datasheet - Page 24

• Manufacturer Part Number: saa7826
• Description: Cd Audio Decoder, Digital Servo And Filterless Dac With Integrated Pre-amp And Laser Control
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 10 Bit assignment
7.12
7.12.1
The KILL circuit detects digital silence by testing for an
all-zero or all-ones data word in the left and right channels.
This occurs in two places; prior to the digital filter (internal
KILL), and in the digital DAC (loopback/external KILL).
Programming bit 3 of new shadow register A (bank 2)
determines whether internal or external data is used. The
output is switched to active HIGH when silence has been
detected for at least 270 ms, or if mute is active, or in
CD-ROM mode. Two KILL modes are available which can
be selected by decoder register C:
7.12.2
The silence inject function monitors the left and right KILL
signals and forces the analog DAC into silence when KILL
is asserted. This improves the internal Signal-to-Noise
Ratio (S/N) by preventing any spurious noise from
reaching the DAC. The silence inject function can be
enabled or disabled by programming bit 2 of the new
shadow register A (bank 2).
2003 Oct 01
Control
Reserved mode
Category code
Clock accuracy
Remaining
Mono KILL: LKILL and RKILL are both active HIGH
when silence is detected on left and right channels
simultaneously
Stereo KILL: LKILL and RKILL are active HIGH
independently of each other when silence is detected on
either channel.
CD audio decoder, digital servo and filterless
DAC with integrated pre-amp and laser control
FUNCTION
KILL features
T
S
HE
ILENCE INJECTION
KILL
CIRCUIT
6 to 27 and
30 to 191
28 to 29
8 to 15
0 to 3
4 to 7
BITS
copy of CRC checked Q-channel control bits 0 to 3; bit 2 is logic 1 when copy
permitted; bit 3 is logic 1 when recording has pre-emphasis
always zero
CD: bit 8 = logic 1, all other bits = logic 0
set by register A; 10 = level I; 00 = level II; 01 = level III
always zero
24
7.13
The audio features can be turned off (selected by decoder
register E) and will affect the following functions:
The EBU output should be set LOW prior to switching the
audio features off and after switching the audio features
back on; a full-scale command should be given.
7.14
The SAA7826 has five pins that can be reconfigured for
different applications.
The functions of these versatile pins are identical to the
SAA732x series and can be programmed by decoder
registers C, D and shadow register 3 (bank 1) as shown in
Table 11.
Digital filter, fade, peak detector, internal KILL circuit
(although RKILL and LKILL outputs are still active) are
disabled
V5 (if selected to be the de-emphasis flag output) and
the EBU outputs become undefined.
Audio features off
The versatile pins interface
DESCRIPTION
Product specification
SAA7826