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