LC78624E Datasheet, PDF (15/27 Pages) Sanyo Semicon Device – Compact Disc Player DSP

LC78624E
• Track jump modes
The table lists the relationships between acceleration pulses (the a period) , deceleration pulses (the b period), and
the braking period (the c period).
Command
1 TRACK JUMP IN (OUT) #1
1 TRACK JUMP IN (OUT) #2
1 TRACK JUMP IN (OUT) #3
a
233 µs
0.5 track
jump period
0.5 track
jump period
1 TRACK JUMP IN (OUT) #4 ^{0.5 track}
jump period
Standard track jump mode
b
c
233 µs
60 ms
233 µs
60 ms
233 µs
233 µs
This period does
not exist.
60 ms; TOFF is
low during
the C period.
2 TRACK JUMP IN (OUT) None
None
None
4 TRACK JUMP IN (OUT)
16 TRACK JUMP IN (OUT)
32 TRACK JUMP IN (OUT)
64 TRACK JUMP IN (OUT)
128 TRACK JUMP IN (OUT)
256 TRACK CHECK
TRACK JUMP BRAKE
2 track
jump period
466 µs
9 track
jump period
7 track
jump period
18 track
jump period
14 track
jump period
36 track
jump period
28 track
jump period
72 track
jump period
56 track
jump period
TOFF goes high during the period
when 256 tracks are passed over.
The a and b pulses are not output.
There are no a or b periods.
60 ms
60 ms
60 ms
60 ms
60 ms
60 ms
60ms
New track jump mode
a
b
c
233 µs
233 µs
60 ms
0.5 track
jump period
The same
time as “a”
60 ms
0.5 track
jump period
The same
time as “a”
This period does
not exist.
0.5 track
jump period
The same
time as “a”
60 ms; TOFF is
low during
the C period.
1 track
jump period
The same
time as “a”
60 ms
2 track
jump period
The same
time as “a”
60 ms
9 track
jump period
The same
time as “a”
60 ms
18 track
jump period
14 track
jump period
60 ms
36 track
jump period
28 track
jump period
60 ms
72 track
jump period
56 track
jump period
60 ms
TOFF goes high during the period
when 256 tracks are passed over.
The a and b pulses are not output.
60 ms
There are no a and b periods.
60 ms
Note: 1. As indicated in the table, actuator signals are not output during the 256 TRACK CHECK function. This is a mode in which the TES signal is counted
in the tracking loop off state. Therefore, feed motor forwarding is required.
2. The servo command register is automatically reset after one cycle of the track jump sequence (a, b, c) completes.
3. If another track jump command is issued during a track jump operation, the content of that new command will be executed starting immediately.
4. The 1 TRACK JUMP #3 mode does not have a braking period (the C period). Since brake mode must be generated by an external circuit, care is
required when using this mode.
5. While there was no braking period (the C period) in the LC78620E/21E for the new track jump command “2 TRACK JUMP IN (OUT)”, this has been
changed in this LSI, which has a C period of 60 ms.
A09910
The THLD signal is generated by the LA9230M, or LA9240M, and the tracking signal is held during the JP pulse period.
No. 5811-15/27