LC78681E Datasheet, PDF (19/23 Pages) Sanyo Semicon Device – Digital Signal Processor for Compact Disc Players

LC78681E
Output for CD-ROM (pin 39: CK2, pin 37: LRSY, pin 40: ROMOUT: pin 42: C2F and pin 41: C2FCLK)
Data from the ROMOUT pin which is synchronized with the LRSY signal is output in MSB-first format. Because this
data has not been processed by either the interpolation, previous-value hold, or digital filtering circuits, it is suitable for
CD-ROM IC input. CK2 is a 2.1168 MHz clock, and data is output on its rising edge. C2F flags 8-bit units of data, and
is synchronized to C2FCLK.
LC8951 and LC78681 Interface
Digital Audio Out Circuit (pin 43: DOUT)
This is the output pin for the digital audio interface, with output in EIAJ format. The signal is output after interpolation
and muting. This output pin has a built-in driver, and can drive a transistor directly.
MSB
LSB
01000010
01000011
01000000
01000001
Command
DOUT ON
DOUT OFF
UBIT ON
UBIT OFF
RES = low
• The digital out pin can be fixed low by issuing the DOUT OFF command.
• The UBIT data in the DOUT data can be fixed at 0 by issuing the UBIT OFF command.
Control Pin (pin 60: CONT)
MSB
LSB
00001110
10001011
Command
CONT set
CONT and CD-ROM XA Reset
RES = low
Low
The CONT pin can be set high by issuing the CONT Set command.
Crystal Oscillator (pin 63: X_IN and pin 64: X_OUT)
MSB
LSB
10001110
10001101
11000001
11000010
01100000
01100001
Command
OSC ON
OSC OFF
Double-speed mode
Normal mode
VCO 8 M
VCO 16 M
RES = low
No. 4521-19/23