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ADAU1761 clicks and pops

Question asked by descazot Employee on Jul 24, 2017

Hello

I'm evaluating ADAU1761 and observes pops and clicks with headphones when output path is modified (speaker to headphones). To avoid it, output is muted before changing the signal path,  I wait 4ms before unmuting headphone output.

Generally speaking, could you tell me when and why pops and clicks can happen? At power on, power off, speaker mode to headphones mode?

 

Thanks for your help.

 

Fyi, please find below my sequencing:

1) Power down core clock and select core clock source from PLL (write 0x0E on register 0x4000)
2) set up ADAU1761's PLL (bulk write of the following bytes 0x00, 0x00, 0x00, 0x00, 0x20, 0x01 starting on address 0x4002)
                3) Wait until ADAU1761's PLL is locked ( Polling the lock bit)
                4) Enable popless mode (setting to 0 POPMODE and POPLESS bits)
                5) Mute the headphone output (setting to 0 the bits LHPM and RHPM)
                6) Enable core clock (writing 0x0F to register address 0x4000)
                7)  Wait for the core clock to be enabled (Sleep for 100ms)
                8) Stop DSP (writing 0x00 to register address 0x40F6)
                9)  Set DSP Sampling rate to 48 KHz (writing 0x01 to register address 0x40EB)
                10) Enable Mixer 1 (MX1EN = 1)
                11)MX1AUXG[2:0] ->  0 dB
                12)  Enable Mixer 2 (MX2EN = 1)
                13) MX2AUXG[2:0] ->  0 dB
                14)  ADCEN[1:0] -> Both on
                15)MX3AUXG[3:0] -> -12 dB
                16) MX4RM -> unmuted
                17) MX4EN -> enabled
                18) MX5EN -> enabled
                19) MX6EN -> enabled
                20) MX7EN -> enabled
                21)Enable playback:  PREN -> enabled, PLEN -> enabled
                22) unmute headphone :  LHPM -> unmuted, RHPM -> unmuted
                23) set headphone volume (left): LHPVOL[5:0] = b111001
                24) set headphone volume (left): RHPVOL[5:0] = b111001
                25) HPMODE -> enable headphone output
                26) sleep for 4 ms
                27) DACEN[1:0]  -> Both on
                28) ADCSDP[1:0] -> pull down, DACSDP[1:0] -> pull down, LRCLKP[1:0] -> pull down, BCLKP[1:0] -> pull down
                29) CDATP[1:0] -> None, CLCHP[1:0] -> None, SCLP[1:0] -> pull-up, SDAP[1:0] -> pull up
                30) Enable DSP,:DSPEN = 1
                31) SINRT[3:0] -> Serial input [L0, R0] to DACs [L, R]
                32) SOUTRT[3:0] -> ADCs [L, R] to serial output [L0, R0]
                33) SLEWPD -> enabled, ALCPD -> enabled, DECPD -> enabled, SOUTPD -> enabled, INTPD -> enabled, SINPD -> enabled, SPPD -> enabled
                34) CLK1 -> enabled, CLK0 -> enabled
                35) Run the DSP: DSPRUN -> 1 (run the DSP)

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