LC78681E Datasheet, PDF (10/23 Pages) Sanyo Semicon Device – Digital Signal Processor for Compact Disc Players

LC78681E
Note: If for Focus Start 2, the value in parentheses is in effect only when FST is low (unlike Focus Start 1).
Notes: 1. The falling edge of FZD is not accepted when FST is low.
2. After a Focus Start command has been issued, the focus servocontroller is reinitialized when RWC goes high.
For this reason, a new command should not be issued until the S-curve for the focus coil drive has been
completed.
3. If focus cannot be reached (i.e., the FZD signal does not go low), the FOCS signal remains high and the lens
remains raised. In this case, the Nothing command should be issued to reinitialize the servocontroller.
4. When the RES pin is set low, LASER is directly set high.
5. Focus start using the DEMO pin is in mode 1.
Constant Linear Velocity Servocontroller (pin 10: CLV ⁺, pin 11: CLV ^– and pin 12: V/P)
MSB
LSB
00000100
00000101
00000110
00000111
Command
DISC MOTOR START (accelerate)
DISC MOTOR CLV (CLV)
DISC MOTOR BRAKE (decelerate)
DISC MOTOR STOP (stop)
RES = low
The disc motor accelerates when CLV⁺ is high and decelerates when CLV^– is high. These outputs are selected by the
motor mode commands issued by the microprocessor (accelerate, decelerate, CLV, or stop). The CLV⁺ and CLV^–
outputs for each mode are shown in the following table.
Accelerate
Decelerate
CLV
Stop
Mode
CLV⁺
High
Low
*
Low
CLV^–
Low
High
*
Low
No. 4521-10/23