SAA7326 Datasheet, PDF (21/68 Pages) NXP Semiconductors – Digital servo processor and Compact Disc decoder with integrated DAC CD10

Philips Semiconductors
Digital servo processor and Compact Disc
decoder with integrated DAC (CD10)
Product specification
SAA7326
7.10 KILL circuit
The KILL circuit detects digital silence by testing for an
all-zero or all-ones data word in the left or right channel
prior to the digital filter. The output is switched to active
LOW when silence has been detected for at least 270 ms,
or if mute is active, or in CD-ROM modes. Two modes are
available which can be selected by decoder register C:
• Pin KILL: KILL active LOW indicates silence detected on
both left and right channels
• Pin KILL: KILL active LOW indicates silence detected on
left channel. V3 active LOW indicates silence detected
on right channel.
It should be noted that when mute is active or in CD-ROM
modes the output(s) are switched LOW.
7.11 Audio features off
The audio features can be turned off (selected by decoder
register E) which affects the following functions;
• Digital filter, fade, peak detector and KILL circuit (but
outputs KILL and V3 still active) are disabled
• V5 (if selected to be the de-emphasis flag output) and
the EBU outputs become undefined.
It should be noted that the EBU output should be set LOW
prior to switching the audio features off and after switching
audio features back on a full-scale command should be
given.
7.12 The VIA interface
The SAA7326 has four pins that can be reconfigured for
different applications. One of these pins, V2/V3, can be
programmed as an input (V2) or as an output (V3). Control
of the V2/V3 pin is via shadow register 3; see Table 9.
Selection of the V2/V3 pin does not affect the function
programmed by decoder register C i.e. the V2/V3 pin can
be changed from V2 to V3 function either before or after
setting the desired function via decoder register 1100.
Selection of, for instance, a V3 function while the V2/V3
pin is set to V2 will not affect the V2 functionality.
The functions of these versatile pins is identical to the
SAA737x series. The functions of these versatile pins is
programmed by decoder registers C and D, as shown in
Table 10.
Table 9 V2/V3 configuration
SHADEN ADDRESS
REGISTER
1
0011 (3H) control of V2/V3 pin
DATA
0XXX
1XXX
FUNCTION
RESET
V2/V3 pin configured as V2 input
reset
V2/V3 pin configured as V3 output (open-drain)
Table 10 Pin applications
PIN NAME
V1
PIN
NUMBER
63
V2
36
V3
36
V4
61
V5
62
TYPE
input
input
output
output
output
REGISTER
ADDRESS
1100
−
−
1100
−
−
1101
−
−
−
1101
−
−
REGISTER
DATA
XXX1
XXX0
−
XX0X
X01X
X11X
0000
XX01
XX10
XX11
01XX
10XX
11XX
FUNCTION
external off-track signal input
internal off-track signal used input may be read via
decoder status bit; selected via register 2
input may be read via decoder status bit; selected
via register 2
KILL output for right channel
output = 0
output = 1
4-line motor drive (using V4 and V5)
Q-to-W subcode output
output = 0
output = 1
de-emphasis output (active HIGH)
output = 0
output = 1
1999 Jun 17
21