AK4586 Datasheet, PDF (21/54 Pages) Asahi Kasei Microsystems – MULTI CHANNEL AUDIO CODEC WITH DIR

ASAHI KASEI
[AK4586]
De-emphasis Filter Control
The AK4586 includes the digital de-emphasis filter (tc=50/15µs) by IIR filter corresponding to three sampling
frequencies (32kHz, 44.1kHz and 48kHz). When DEAU bit = “1”, the de-emphasis filter is enabled automatically by
sampling frequency and pre-emphasis information in the channel status. The AK4586 goes to this mode at default and the
de-emphasis filter is controlled by the status bits in channel 1 (Table 8). DEM1-0 and DFS bits can control the
de-emphasis filter when DEAU is “0” (Table 9). The internal de-empahsis filter is bypassed and the recovered data is
output without any change if either pre-emphasis or de-emphasis mode is OFF. The internal de-emphasis filter is
bypassed if the Non-PCM or the DTS-CD bitstream is detected at DEAU= “1”. The internal de-emphasis filter is
bypassed if bit 0 of the channel status byte 0 is “1”.
RFS96
FS1
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
FS0
DEM
0
44.1kHz
1
OFF Default
0
48kHz
1
32kHz
0
OFF
1
OFF
0
OFF
1
OFF
Table 8. De-emphasis Auto Control at DEAU=“1” and PEM=“1”
Sampling Speed
Normal Speed
Normal Speed
Normal Speed
Normal Speed
Double Speed
Double Speed
Double Speed
Double Speed
DEM1
0
0
1
1
0
0
1
1
DEM0
0
1
0
1
0
1
0
1
DEM
44.1kHz
OFF
48kHz
32kHz
OFF
OFF
OFF
OFF
Default
Table 9. De-emphasis Manual Control at DEAU=“0” and PEM=“1”
System Reset and Power-Down
The AK4586 has a power-down mode for all circuits by PDN pin or can be partially powered-down by internal register.
The AK4586 should be reset once by bringing PDN pin = “L” upon power-up. ADC, DAC and PLL are powered-down at
PWVRN= “0”.
PDN
L
x
x
x
x
x
x
PWADN
x
0
x
x
x
x
x
PWDAN
x
x
0
x
x
x
x
PWVRN
x
x
x
0
x
x
x
RSTN
x
x
x
x
0
x
x
CM1-0
x
x
x
x
x
00
01
Function
All power down
ADC power down
DAC power down
VREF power down
Timing Reset
X’tal power down
PLL power down
Register initialization
Yes
No
No
No
No
No
No
Table 10. Reset & Power Down
MS0097-E-01
- 21 -
2001/12