LC7861KE View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

Manufacturer

LC7861KE

Digital Signal Processor for Compact Disc Players

SANYO -> Panasonic 

LC7861KE

9. Focus servo circuit; Pin 13: FOCS, pin 14: FST, pin 15: FZD, pin 57: LASER

Commands

MSB

LSB

00001000

10100010

00001010

10001010

00000000

Command

FOCUS START #1

FOCUS START #2

LASER ON

LASER OFF

NOTHING

RES = low

o

When a focus start instruction (either FOCUS START #1 or FOCUS START #2) is input as a servo command, first

the charge on capacitor C1 is discharged by FST and the objective lens is lowered. Next, the capacitor is charged by

FOCS, and the lens is slowly raised. FZD falls when the lens reaches the focus point. When this signal is received,

FOCS is reset and the focus servo turns on. After sending the command, the microprocessor should check DRF to

confirm focus before proceeding to the next part of the program. If focus is not achieved by the time C1 is fully

charged, the microprocessor should issue another focus command and iterate the focus servo operation.

• LASER control

• Focus start (Values in parentheses are for the LASER START #2 command. The only difference is in the FST low

period.)

— An FZD falling edge will not be accepted during the period that FST is low.

— 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.

— When focus cannot be achieved (i.e., when FZD does not go low) the FOCS signal will remain in the high

state, so the microprocessor should initialize the system by issuing a NOTHING command.

— When the RESET pin is set low, the LASER pin is set high directly.

— Focus start using the DEMO coil executes a mode #1 focus start.

No. 4818-10/18

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