LC78681E Datasheet, PDF (14/23 Pages) Sanyo Semicon Device – Digital Signal Processor for Compact Disc Players

LC78681E
3. Track Jump Modes
The relationship between acceleration pulses, deceleration pulses, and brake periods is shown in the following table.
Command
Standard track jump mode
a
b
c
New track jump mode
a
b
c
1 TRACK JUMP IN (OUT) #1 233 µs
233 µs
24 ms
233 µs
233 µs
24 ms
1 TRACK JUMP IN (OUT) #2 0.5-track jump
233 µs
24 ms
0.5-track jump
a period
24 ms
1 TRACK JUMP IN (OUT) #3 0.5-track jump
233 µs
Does not occur 0.5-track jump
a period
Does not occur
2 TRACK JUMP IN (OUT)
There are no a, b, or c periods.
1-track jump
a period
Does not occur
4 TRACK JUMP IN (OUT)
2-track jump
466 µs
24 ms
2-track jump
a period
24 ms
16 TRACK JUMP IN (OUT) 9-track jump
7-track jump
24 ms
9-track jump
a period
24 ms
32 TRACK JUMP IN (OUT) 18-track jump
14-track jump
24 ms
18-track jump
14-track jump
24 ms
64 TRACK JUMP IN (OUT) 36-track jump
28-track jump
24 ms
36-track jump
28-track jump
24 ms
128 TRACK JUMP IN (OUT) 72-track jump
56-track jump
24 ms
72-track jump
56-track jump
24 ms
256 TRACK CHECK
TOFF goes high after 256 tracks are
jumped. The a and b pulses are not
output.
24 ms
TOFF goes high after 256 tracks are
jumped. The a and b pulses are not
output.
24 ms
TRACK JUMP BRAKE
There are no a or b periods.
24 ms
There are no a or b periods.
24 ms
Notes: 1. The actuator drive signals are not generated for the 256-track Check. Instead issuance of a feed motor signal is required because the TES signal
is in the track-count mode and the tracking servocontroller is off.
2. The servocontroller register is automatically reset after one a, b, and c track jump sequence.
3. When a new track jump command is issued while a previous command is still being processed, the new command is executed immediately.
4. Track Check Mode
MSB
LSB
11110000
11111000
11111111
Command
Track Count In
Track Count Out
2-byte COMMAND RESET
RES = low
A Track Count In or Track Count Out command followed by a binary number between 16 and 256 can be used to
start track counting for the specified number of tracks.
No. 4521-14/23