LC78621E Datasheet, PDF (12/34 Pages) Sanyo Semicon Device – Compact Disc Player DSP

LC78621E
Values in parentheses are for the LASER START #2 command. The only difference is in the FST low period.
Note: 1. An FZD falling edge will not be accepted during the period that FST is low.
2. After issuing a focus start command, initialization will be performed if RWC is set high. Therefore, do
not issue the next command during focus start until the focus coil drive S curve has completed.
3. When focus cannot be achieved (i.e., when FZD does not go low) the FOCS signal will remain in the
high state and the lens will remain raised, so the microprocessor should initialize the system by issuing a
NOTHING command.
4. When the RESET pin is set low, the LASER pin is set high directly.
5. Focus start using the DEMO pin executes a mode #1 focus start.
7. CLV servo circuit; Pin 13: CLV⁺, pin 14: CLV^–, pin 15: 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
q
The CLV⁺ pin provides the signal that accelerates the disk in the forward direction and the CLV^– pin provides the
signal that decelerates the disk. Commands from the control microprocessor select one of four modes; accelerate,
decelerate, CLV and stop. The table below lists the CLV⁺ and CLV^– outputs in each of these modes.
Mode
Accelerate
Decelerate
CLV
Stop
CLV⁺
High
Low
*
Low
CLV^–
Low
High
*
Low
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