LC78626 Sanyo Semicon Device, LC78626 Datasheet - Page 22

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

11 The Bilingual Function
12 Deemphasis Pin 45: EMPH
13 The Digital Attenuator
* At reset or when a stereo command ($28) has been entered, Lch and Rch are output, respectively, to Lch and Rch.
* When the Lch set command ($29) is entered, the Lch data is output to both Lch and Rch.
* When the Rch set command ($2A) is entered, the Rch data is output to both Lch and Rch.
Of the subcode Q control data, the pre-emphasis On/Off bit is output from the EMPH pin. When this pin is high, the
deemphasis circuit within this IC is activated, and the D/A converter output are de-emphasized.
It is possible to apply digital attenuation to the audio data by setting the RWC high and inputting from the COIN a
two byte command synchronized with the CQCK clock.
After reset, the attenuation level is set to “MUTE” (the attenuation coefficient is 00H, where MUTE = –∞), and thus
it is necessary to directly set the attenuation coefficient EEH using the direct set (ATT DATA SET) command in
order to produce a sound. The attenuation level can be set to a range from 00H to EEH (239 different levels) by the
microcontroller commands.
This two byte command is different from the two byte commands used in track counting in that RWC only needs to
be set once, and it is not necessary to reset the two byte command either. (See the two byte command RWC1 set on
page 13.)
After inputting the target attenuation level in terms of 00H to EEH, then if the attenuate step-up/step-down
commands are transmitted, the system steps closer to the target with the corresponding step size of 4, 8, or 16,
synchronized with the rising edge of LRSY. However, when the ATT DATA SET command has been used, then the
target value is set directly. When new data is entered during the transition, then the target value is approached from
whatever value is in effect at that time. Caution is required when using the step-up/step-down commands at this time.
Code
Code
$28
$29
$2A
$81
$82
$83
$84
$85
$86
$87
Command
ATT
ATT
ATT
ATT
ATT
ATT
ATT
Attenuation data 00H to EEH
COMMAND
COMMAND
STO CONT
Rch CONT
Lch CONT
DATA
4STEP
4STEP
8STEP
8STEP
16STEP
16STEP
SET
UP
DOWN
UP
DOWN
UP
DOWN
LC78626E
Attenuate set command
DATA 00H Set
(MUTE –∞dB)
RES = low
RES = low
No. 5692-22/32