ADAU1361, when Power-On/Off, noise occurs on the HP output
Please let me ask you how to suppress the Headphone output noise.
When Power-On/Off sequence on the ADAU1361, noise occurs on the HP output.
Unfortunately I cannot avoid the noise ...
How order should we set the register ? Or should we apply any countermeasures on the hardware ?
1. Power-ON
I set register as following sequence. Then a small noise occurs.
- R22,24 register, Mixer3/4 setting
- R33 register , MONO setting
- R29,30 register ,RHPM RHPM setting
I have checked below. But the noise still appears.
data sheet ( rev.C ) Page 36
( Figure 45. Headphone Output Power-Up Timing )
> To prevent pops when turning on the headphone outputs, the
> user must wait at least 4 ms to unmute these outputs after
> enabling the headphone output with the HPMODE bit.
If I wait several seconds after Mixer3/4 setting, I can avoid the noise, I confirmed.
But the wait time is too long to implement on our system...
2. Power off.
Pop noise occurs.
I have checked and operate as written in below.
But I cannot avoid the noise ...
data sheet ( rev.C ) Page 36
( Figure 46. Headphone Output Power-Down Timing )
If you have any ideas,
would you please let me know ?
adau1361
Integrated/Special Purpose A/D Converters
Audio CODECs
I have tested on the evaluation board, EVAL-ADAU1761Z.
Unfortunately I don'T have the EVAL-ADAU1361Z.
But I think we can get same result ...
As written in the data sheet, I operated the register on the sequece window of the Sigma Studio.
But I sitll heared small pop noise.
Can not we avoid the small noise on the ADAU1761/1361 ?
If you can find any problems in the following operations, please let me know.
< Power ON seqenece >
Write all registers
0x4027 0xE5 ( register R33 , LineOUT to HPOUT )
0x4027 0xE7 ( register R33 , Mute to UnMute )
0x4024 0xE5 ( register R30 , HPMODE : LineOUT to HPOUT )
( over 4msec wait )
0x4023 0xE7 ( register R29 , LHPM : Mute to UnMute )
0x4024 0xE7 ( register R30 , RHPM : Mute to UnMute )
< Power Off sequence >
0x4023 0xE5 ( register R29 , LHPM : UnMute to Mute )
0x4024 0xE5 ( register R30 , RHPM : UnMute to Mute )
( wait )
0x4024 0xE4 ( register R30 , HPMODE : HPOUT to LineOUT )
0x4027 0xE5 ( register R33 , UnMute to Mute )
0x4027 0xE4 ( register R33 , HPOUT to LineOUT )
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Thank you,
EZ Admin
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