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PCM9211: PLL not getting a lock with audio input

Part Number: PCM9211

Tool/software:

Currently we are applying 1412 kb/s, 44.1KHz, 16 bits, 2ch, FLAC signal on the RXIN2 input of PCM9211 IC.

After configuring the IC we are getting no output on the main output port. Upon inspecting, we found that PLL is not getting a lock and registers 0x38 and 0x39 are showing values of 80h.

Below are the setting we performed after startup,

Reg -> Value

0x40 -> 0xE2      (Disable ADC and DIT)

0x6B -> 0x11      (DIR as main port source)

0x34 -> 0xC2      (RXIN2 as DIR source)

0x37 -> 0x00      (This is default value but i tried it either way)

0x26 -> 0x81      (Tried changing the ADC clock source even though ADC was turned off)

0x30 -> 0x12      (Enable PSCKAUTO to autoselect PLL SCK)

 

Using stm32f401RCT6 MCU as DSP and using DMA in circular mode to receive data over i2s protocol.
PCM9211 schematic is attached.

https://imgur.com/a/38cFR7p

  • Hello Ferhan,

    Here is a script that you can use and get the system initialize and get it  to work. Once it is running, you can do modifications as you need . In general you can  refer to user's guide for reference schematics or our dedicated EVM. PCM9211 has a reference schematic in SBAU174 user's guide


    4314.PCM9211_Init.txt
    #**************************************
    #this script is for SPDIF-->RXIN0-->DIR-->MainOutput, Record sound from SPDIF to PC through TAS1020
    
    #So
    #1, Chose RXIN0 to DIR
    #2, Active DIR
    #3, chose DIR output as Mainoutput's source.
    
    #Also HW modification
    #1, Flying to High Level(3.3V) to make sure U7's output is Hi-Z
    #or 2, TAS1020 output logic high on P1.2 I2S enable signal. 
    #**************************************
    
    
    #System RST Control
    #w 80 40 00
    w 80 40 33
    w 80 40 C0
    
    #XTI Source, Clock (SCK/BCK/LRCK) Frequency Setting
    # XTI CLK source 12.288 and BCK 3.072, LRCK 48k = XTI/512
    w 80 31 1A
    w 80 33 22
    w 80 20 00
    w 80 24 00
    #ADC clock source is chosen by REG42
    w 80 26 81
    
    #XTI Source, Secondary Bit/LR Clock (SBCK/SLRCK) Frequency Setting
    w 80 33 22
    
    
    #*********************************************************
    #-------------------------------Start DIR settings---------------------------------------
    #REG. 21h, DIR Receivable Incoming Biphase's Sampling Frequency Range Setting
    w 80 21 00
    
    #REG. 22h, DIR CLKSTP and VOUT delay
    w 80 22 01
    
    #REG. 23h, DIR OCS start up wait time and Process for Parity Error Detection and ERROR Release Wait Time Setting
    w 80 23 04
    
    # REG 27h DIR Acceptable fs Range Setting & Mask
    w 80 27 00
    
    # REG 2Fh, DIR Output Data Format, 24bit I2S mode
    w 80 2F 04
    
    # REG. 30h, DIR Recovered System Clock (SCK) Ratio Setting
    w 80 30 02
    
    #REG. 32h, DIR Source, Secondary Bit/LR Clock (SBCK/SLRCK) Frequency Setting
    w 80 32 22
    
    #REG 34h DIR Input Biphase Signal Source Select and RXIN01 Coaxial Amplifier
    #--PWR down amplifier, Select RXIN2
    #w 80 34 C2
    #--PWR up amplifier, select RXIN0
    w 80 34 00
    #--PWR up amplifier, select RXIN1
    #w 80 34 01
    
    #REG. 37h, Port Sampling Frequency Calculator Measurement Target Setting, Cal and DIR Fs
    w 80 37 00
    #REG 38h rd DIR Fs
    r 80 38 01
    #***********************************************************
    #------------------------------------ End DIR settings------------------------------------------
    
    
    #***********************************************************
    #---------------------------------Start  MainOutput Settings--------------------------------------
    #MainOutput
    #REG. 6Ah, Main Output & AUXOUT Port Control
    w 80 6A 00
    
    #REG. 6Bh, Main Output Port (SCKO/BCK/LRCK/DOUT) Source Setting
    w 80 6B 11
    
    #REG. 6Dh, MPIO_B & Main Output Port Hi-Z Control
    w 80 6D 00
    #***********************************************************
    #------------------------------------ End MainOutput settings------------------------------------------
    
    # read back all registers to ensure GUI integrity
    r 80 20 5E
     

    Regards,

    Arash

  • Hello Arash, Thanks for the script.

    I tried the settings in the script and changed the input source from RXIN0 to RXIN2 but still our PLL is not getting a lock on the input frequency and there is no output on main port.

    I checked the input signal on RXIN2 and this is the waveform im getting. But this signal is working fine with a soundbar.

    https://imgur.com/a/07Tu8fZ

    Let me know if any of this makes sense or if im missing anything.

    Thanks

  • Hello Farhan,

    An input format that works fine for a given system or application might not be the acceptable format for another system. The input that you are showing doesn't look correct to me. Having said that you have to always look at the input and various clks together. For example you may not see much a difference b/w I2S and LJ but a system might expect I2S and you are sending RJ. see Figure 7-2. Audio Data Input/Output Formats

    Since you have a full  script and you don't get anything at the output , probably the format is not what it is expected and it can not lock. When the DIR encounters an error (for example, when it loses a lock), an error signal can be configured and  sent to the ERROR pin (pin 1). Control of pin 1 (ERROR or Int0) is set by Register 20h.

    So try to monitor errors and that should give you a hint of the issue. read more on register maps such as  7.5.6 Error Cause Setting Register (address = 25h) 

    Regards,

    Arash

  • Hello, Thanks for the reply but my issue was resolved after i resolved the input signal, grounding capasitor was distorting the signal to such extent that PLL was not getting a lock on it.

  • Hello, I don't see any cap at the input in the schematic, but good to hear it is resolved. Thanks for the update.

    Regards,

    Arash

  • Hello, i see that i havent attached the schematic for toslink connector


    Here, C27 is the capacitor that was removed

    Thank you for the support.

  • Hi Farhan. Thanks for adding the input schematics.

    Regards,

    Arash