AK4537 Datasheet, PDF (66/76 Pages) Asahi Kasei Microsystems – 16-Bit ΔΣ Stereo CODEC with MIC/HP/SPK-AMP

ASAHI KASEI
[AK4537]
„ MIC Input Recording (Mono)
FS2-0 bits ₀₀₀
(Addr:05H, D7-5)
(1)
MIC Control
(Addr:07H, D2-0)
00001
(2)
ALC1 Control 1 _XXH
(Addr:08H)
(3)
ALC1 Control 2 _XXH
(Addr:0AH)
(4)
ALC1 Control 3
(Addr:09H)
ALC1 State
XXH
(5)
ALC1 Disable
XXX
XX1XX
00H
47H
61H or 21H
ALC1 Enable ALC1 Disable
PMADL bit
(Addr:00H, D0)
PMMICL bit
(Addr:00H, D1)
ADC Internal
State
(6)
(7)
2081 / fs
Power Down
Initialize Normal State Power Down
Example :
X’tal and PLL are used.
Sampling Frequency : 8kHz
Mic Select : Internal Mic
Pre Mic AMP : +20dB
MIC Power On
ALC1 setting : Refer to Figure 9
ALC2 bit = “1”(default)
(1) Addr:05H, Data:E0H
(2) Addr:07H, Data:0DH
(3) Addr:08H, Data:00H
(4) Addr:0AH, Data:47H
(5) Addr:09H, Data:61H
(6) Addr:00H, Data 83H
Recording
(7) Addr:00H, Data 80H
Figure 54. MIC Input Recording Sequence
<Example>
This sequence is an example of ALC1 setting at fs=8kHz. If the parameter of the ALC1 is changed, please refer to
“Figure 22. Registers set-up sequence at ALC1 operation”
At first, clocks should be supplied according to “Clock Set Up” sequence.
(1) Set up a sampling frequency (FS2-0 bits). When the AK4536 is PLL mode, MIC and ADC should be
powered-up in consideration of PLL lock time after a sampling frequency is changed.
(2) Set up MIC input (Addr: 07H)
(3) Set up Timer Select for ALC1 (Addr: 08H)
(4) Set up REF value for ALC1 (Addr: 0AH)
(5) Set up LMTH, RATT, LMAT1-0, ALC1 bits (Addr: 09H)
(6) Power Up MIC and ADC: PMMICL bit = PMADL bit = “0” → “1”
(In case of stereo mic, PMMICR and PMADR bits also should be set to “1”.)
The initialization cycle time of ADC is 2081/fs=47.2ms@fs=44.1kHz.
After the ALC1 bit is set to “1” and MIC block is powered-up, the ALC1 operation starts from IPGA initial
value (0dB).
(7) Power Down MIC and ADC: PMMIC bit = PMADC bit = “1” → “0”
(In case of stereo mic, PMMICR and PMADR bits also should be set to “0”.)
When the registers for the ALC1 operation are not changed, ALC1 bit may be keeping “1”. The ALC1
operation is disabled because the MIC block is powered-down. If the registers for the ALC1 operation are also
changed when the sampling frequency is changed, it should be done after the AK4537 goes to the manual
mode (ALC1 bit = “0”) or MIC block is powered-down (PMMICL bit = “0”). IPGA gain is reset when
PMMICL =PMMICR=PMIPGL=PMIPGR= “0”, and then IPGA operation starts from the default value when
PMMICL, PMMICR, PMIPGL or PMIPGR bit is changed to “1”.
MS0202-E-04
- 66 -
2005/04