LC78681E Datasheet, PDF (13/23 Pages) Sanyo Semicon Device – Digital Signal Processor for Compact Disc Players

2. Track Jump Commands
MSB
LSB
10100000
10100001
00010001
00010010
00110001
00010000
00010011
00010100
00110000
00010101
00010111
00011001
00011010
00111001
00011000
00011011
00011100
00111000
00011101
00011111
00010110
00001111
10001111
10001100
LC78681E
Command
Standard track jump
New track jump
1 TRACK JUMP IN #1
1 TRACK JUMP IN #2
1 TRACK JUMP IN #3
2 TRACK JUMP IN
4 TRACK JUMP IN
16 TRACK JUMP IN
32 TRACK JUMP IN
64 TRACK JUMP IN
128 TRACK JUMP IN
1 TRACK JUMP OUT #1
1 TRACK JUMP OUT #2
1 TRACK JUMP OUT #3
2 TRACK JUMP OUT
4 TRACK JUMP OUT
16 TRACK JUMP OUT
32 TRACK JUMP OUT
64 TRACK JUMP OUT
128 TRACK JUMP OUT
256 TRACK CHECK
TOFF
TON
TRACK JUMP BRAKE
RES = low
When a track jump command is issued to the servocontroller, an acceleration pulse is generated (a period), followed
by a deceleration pulse (b period) and braking (c period), completing the specified jump. TES and HFL input during
braking detects the direction of beam slippage, and the portion of the TE signal that compensates for slippage is cut
off by TOFF, which, together with boosting of the servo gain by TGL, supplements the destination track for the
jump.
Note: Of the disc motor control outputs, the TOFF pin is low in the CLV mode, and high in the Start Stop, and Brake
modes. TOFF can also be independently switched on or off by the microprocessor. However, disc motor control
is enabled only in the CLV mode.
No. 4521-13/23