HD49235 데이터 시트보기 (PDF) - Hitachi -> Renesas Electronics

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HD49235

Digital Signal Processor for CD

Hitachi -> Renesas Electronics 

HD49235FS

QOK: The output at this pin indicates whether or not the Q subcode is correct.

One block of Q subcode data consists of 98 bits, of which 16 bits are parity bits that indicate whether

the data read from the disc was correct or in error. An on-chip cyclic redundancy check circuit decides

whether the 98-bit data string is correct or not, and outputs the result at the QOK pin. A high-level

output indicates OK. Figures 7 and 8 show the output timing.

In modes using the Q code buffer register, when the microprocessor sets the CRCQ bit to 1, QOK is

inserted in QDATA at the rise of S1.

See the note in the timing chart shown in figure 7.

EMP: This output pin indicates the presence or absence of pre-emphasis. The pre-emphasis signal is

detected from the Q subcode and output at the EMP pin. High output indicates audio with pre-emphasis.

Low output indicates audio without

pre-emphasis.

SUBOUT: This pin outputs codes R to W for use in display of graphics.

CFCKP: This pin outputs a subcode frame synchronization signal.

S1

QOK

CKEXT

1 2345

80

1 23

QDATA

*

Q4 Q3 Q2 Q1 Q8

Q77

*

Q4 Q3 Q2

Note: * Undefined when CRCQ = 0; QOK when CRCQ = 1 (high when CRC result is OK)

Figure 7 Timing When QDSEL is Low (Q Code Buffer Mode)

CKEXT

CFCKP

7.35 kHz

QDATA

Q96

S0

S1

Q1

S1

QOK

CRC result data: high when OK

Figure 8 Timing When QDSEL is High(Q Code Internal Synchronization Mode,

Standard Speed Playback)

Rev.2, Aug. 1995, page 20 of 41

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