SAA7324H NXP Semiconductors, SAA7324H Datasheet - Page 31

• Manufacturer Part Number: SAA7324H
• Manufacturer: NXP Semiconductors

Specifications of SAA7324H

• Operating Temperature (max): 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 64
• Lead Free Status / Rohs Status: Compliant

Philips Semiconductors
7.14.7
During active radial tracking, off-track detection has been
realised by continuously monitoring the off-track counter
value. The off-track flag becomes valid whenever the
off-track counter value is not equal to zero. Depending on
the type of extended S-curve, the off-track counter is reset
after 0.75 extend or at the original track in the 2.25 track
extend mode.
7.14.8
7.14.8.1
The STATUS pin is an output which is active LOW, its
output is selected by decoder register 7 to be either the
decoder status bit (active LOW) selected by decoder
register 2 (only available in 4-wire bus mode) or the
interrupt signal generated by the servo part.
Eight signals from the interrupt status register are
selectable from the servo part via the interrupt_mask
parameter. The interrupt is reset by sending the read
high-level status command. The 8 signals are as follows:
It should be noted that if the STATUS pin output is selected
via decoder register 2 and either the microcontroller writes
a different value to decoder register 2 or the decoder
interface is enabled then the STATUS output will change.
7.14.8.2
The decoder interface allows decoder registers 0 to F to
be programmed and subcode Q-channel data to be read
via servo commands. The interface is enabled/disabled by
the preset latch command (and the xtra_preset
parameter).
2000 Jun 26
Focus lost: dropout of longer than 3 ms
Subcode ready
Subcode absolute seconds changed
Subcode discontinuity detected: new subcode time
before previous subcode time, or more than 10 frames
later than previous subcode time
Radial error: during radial on-track, no new subcode
frame occurs within time defined by the ‘playwatchtime’
parameter; during radial jump, less than 4 tracks have
been crossed during time defined by the
‘jumpwatchtime’ parameter
Autosequencer state change
Autosequencer error
Subcode interface blocked: the internal decoder
interface is being used.
Digital servo processor and Compact Disc
decoder with integrated DAC (CD10 II)
O
H
IGH
FF
Interrupt mechanism and STATUS pin
Decoder interface
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TRACK DETECTION
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LEVEL FEATURES
31
7.14.8.3
Three Watchdogs are present:
The focus Watchdog is always active, the radial
Watchdogs are selectable via the radcontrol parameter.
7.14.8.4
Two automatic sequencers are implemented (and must be
initialized after power-on):
When the automatic sequencers are not used it is possible
to generate timer interrupts, defined by the
time_parameter coefficient.
7.14.8.5
The read high-level status command can be used to obtain
the interrupt, decoder, autosequencer status registers and
the motor start time. Use of the read high-level status
command clears the interrupt status register, and
re-enables the subcode read via a servo command.
7.14.9
The control signals (pins RA, FO and SL) for the
mechanism actuators are pulse density modulated.
The modulating frequency can be set to either
1.0584 (DSD mode) or 2.1168 MHz; controlled via the
xtra_preset parameter. An analog representation of the
output signals can be achieved by connecting a 1st-order
low-pass filter to the outputs.
Focus: detects focus dropout of longer than 3 ms, sets
focus lost interrupt, switches off radial and sledge
servos, disables drive to disc motor
Radial play: started when radial servo is in on-track
mode and a first subcode frame is found; detects when
maximum time between two subcode frames exceeds
the time set by playwatchtime parameter; then sets
radial error interrupt, switches radial and sledge servos
off, puts disc motor in jump mode
Radial jump: active when radial servo is in long jump or
short jump modes; detects when the off-track counter
value decreases by less than 4 tracks between two
readings (time interval set by jumpwatchtime
parameter); then sets radial jump error, switches radial
and sledge servos off to cancel jump.
Autostart sequencer: controls the start-up of focus,
radial and motor
Autostop sequencer: brakes the disc and shuts down
servos.
D
RIVER INTERFACE
Automatic error handling
Automatic sequencers and timer interrupts
High-level status
Product specification
SAA7324