LC89170M 데이터 시트보기 (PDF) - SANYO -> Panasonic

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LC89170M

CD Player Text Data IC

SANYO -> Panasonic 

LC89170M

• Synchronizing signal interpolation and protection

Although the LC89170M receives data from the DSP over the subcode interface, it is possible that due to reasons such as

defects or damage to the disk, errors may occur in the synchronization pattern (SO, SI) making the LC89170M unable to

detect that synchronization pattern, or a signal that is not a synchronizing signal (SCOR) may be recognized as a

synchronizing signal making the LC89170M unable to correctly read out the data. The LC89170M includes a

synchronizing signal interpolation and protection circuit to handle these problems. Figure 4 describes this interpolation

and protection circuit.

Although the interpolation circuit generates a synchronization signal for each packet, if the synchronizing signal is

missing, it resets on the next detected synchronizing signal and once again generates a synchronizing signal for each

packet. (1)

In the protection circuit, when a synchronizing signal is detected, if that synchronizing signal does not meet the stipulated

period (98 × WFCK) with respect to the previously detected synchronizing signal, the protection circuit has the

LC89170M ignore that detected synchronizing signal. This prevents signals that are not synchronizing signals from being

mistakenly recognized as synchronizing signals. (2)

The processing performed by these circuit is reflected in the CRC flags.

Figure 4 Synchronizing Signal Interpolation and Protection

At the point marked (1) in the figure, an external SCOR that differs from the interpolated was detected, and here the

interpolation circuit is synchronized with this signal.

At the point marked (2) in the figure, an external SCOR that differs from the interpolated was detected, but this external

SCOR will be ignored and the interpolation circuit will not be re-synchronized.

• System reset and low power mode

The XMODE pin functions to reset the system and to switch to low power mode. System operation can be started

correctly by applying a high level to this pin after the power-supply voltage has risen above 4.5 V (or 3.0 V). Setting the

XMODE pin low switches the LC89170M to low power mode.

Application Circuit Example

No. 5536-7/8

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