LC78626 Sanyo Semicon Device, LC78626 Datasheet - Page 16

• Manufacturer Part Number: LC78626
• Description: DSP for Compact Disk Players
• Manufacturer: Sanyo Semicon Device

(5) The Internal Brake Mode
7 The Track Jump Circuit Pin 23: HFL, Pin 24: TES, Pin 25: TOFF, Pin 26: TGL, Pin 27: JP
(1) Types of Track Counters
* The internal brake mode is turned on by inputting the internal brake on command ($C5). When in this mode, when
* In this mode, the status of deceleration of the disk is determined by counting the density of the EFM signals in a
When noise in the EFM signal causes the deceleration status to be judged incorrectly, it may be advisable to use the
internal break control command ($A3) to change the EFM signal count from 4 to 8.
* In the TOFF output inhibited mode ($CD), TOFF is low while the internal break is in operation. Its use is
* When there is a loss of focus during the execution of an internal break command it will be necessary to reissue the
* Because there is a risk that the EFM signal will be discerned incorrectly depending on the playback status
* When the internal brake mode is in effect, then it is possible to monitor the disk deceleration status at the WRQ Pin
The following two track count modes have been provided.
The conventional track counter uses the TES signal itself as the internal track counter clock. In the new track count
method, however, the TES signal is combined with the HFL signal to reduce the amount of noise, producing a more
accurate track count through reducing the number of miscounts due to noise in the rising edge and falling edge of the
TES signal. However, when the HFL signal is absent because of dust, scratches, etc., there is the danger that there
will be no track count pulse, and thus caution is required when using this method.
the brake command ($06) is executed it becomes possible to monitor the state of deceleration of the disk using the
WRQ pin.
single frame, and the CLV
put to high as the break complete monitor. The microcontroller issues the STOP command if it senses that the
WRQ signal is high, and thus brings the disk to a complete stop. In the internal break continuous mode the CLV
high brake operation continues even when the break complete monitor WRQ goes high.
recommended because it is effective in preventing incorrect detection at the mirrored surface of the disk.
internal brake command after the focus has been reestablished.
(scratched disks, access processes, etc.), use in conjunction with the microcontroller is recommended.
by executing the DISC MTR BRAKE command ($06) in this DSP. However, if another command is executed
while this command is in process, then the command will be aborted. When you wish to prevent the function from
being aborted, then, after issuing the DISC MTR BRAKE command ($06), do not issue any other commands until
a high WRQ signal is detected and the DISC MTR STOP command ($07) is issued.
Code
Code
$CD
$CC
$C5
$C4
$CB
$CA
$22
$23
$A3
$06 command
EFM signal
The conventional track count (direct count of the TES signal).
Internal brake continuous mode reset
The new track count (a combination of TES and HFL).
Internal brake continuous mode
Internal brake TON mode reset
Internal brake TON mode
Internal brake control
Internal Break OFF
Internal Break ON
–
is low if the number of EFM signals is 4 or less. At the same time, the WRQ signal is
COMMAND
COMMAND
LC78626E
RES = low
RES = low
+
, Pin 28: JP
No. 5692-16/32
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–
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