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PCM5142: Purepath - No Audio Output on some configurations

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Replies: 5

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Part Number: PCM5142

Hi,

I'm developing with the PCM5142 and PurePath studio in a custom setup (not the dev kit). I can load programs into the DSP and read out the memory to verify that they are loaded correctly, but I only get audio output for some programs.

I have tried the following as a test, which functioned correctly (although the audio quality wasn't as good as I was expecting?):

However, when I try include a parametric EQ (which is the intended functionality) as shown below, I get no audio output whatsoever:

The EQ is currently set up as shown below, and is configured for the rates shown in the picture, though it is being loaded onto the DSP and tested at 44.1kHz:

I am also using a 3 wire I2S interface and thus have a custom clock setup which is detailed in the following image:

I have verified that this clocking structure is being loaded onto the PCM5142 correctly, and it is listed in the datasheet as one of the known good configurations (page 109 table 132).

Below is a readout of the chips registers - the "contents" field is hexadecimal:

Page 0:

Register: 001 Contents: 00
Register: 002 Contents: 00
Register: 003 Contents: 00
Register: 004 Contents: 01
Register: 005 Contents: 11
Register: 006 Contents: 00
Register: 007 Contents: 00
Register: 008 Contents: 04
Register: 009 Contents: 00
Register: 010 Contents: 00
Register: 011 Contents: 01
Register: 012 Contents: 7c
Register: 013 Contents: 10
Register: 014 Contents: 10
Register: 015 Contents: 00
Register: 016 Contents: 00
Register: 017 Contents: 00
Register: 018 Contents: 00
Register: 019 Contents: 10
Register: 020 Contents: 00
Register: 021 Contents: 20
Register: 022 Contents: 00
Register: 023 Contents: 00
Register: 024 Contents: 01
Register: 025 Contents: 00
Register: 026 Contents: 80
Register: 027 Contents: 01
Register: 028 Contents: 0f
Register: 029 Contents: 03
Register: 030 Contents: 07
Register: 031 Contents: 04
Register: 032 Contents: 00
Register: 033 Contents: 00
Register: 034 Contents: 10
Register: 035 Contents: 04
Register: 036 Contents: 00
Register: 037 Contents: 1a
Register: 038 Contents: f3
Register: 039 Contents: 04
Register: 040 Contents: 00
Register: 041 Contents: 00
Register: 042 Contents: 11
Register: 043 Contents: 1f
Register: 044 Contents: 00
Register: 045 Contents: 00
Register: 046 Contents: 00
Register: 047 Contents: 00
Register: 048 Contents: 00
Register: 049 Contents: 00
Register: 050 Contents: 00
Register: 051 Contents: 00
Register: 052 Contents: 00
Register: 053 Contents: 00
Register: 054 Contents: 00
Register: 055 Contents: 00
Register: 056 Contents: 00
Register: 057 Contents: 00
Register: 058 Contents: 00
Register: 059 Contents: 00
Register: 060 Contents: 00
Register: 061 Contents: 30
Register: 062 Contents: 30
Register: 063 Contents: 22
Register: 064 Contents: 02
Register: 065 Contents: 07
Register: 066 Contents: 14
Register: 067 Contents: 05
Register: 068 Contents: 00
Register: 069 Contents: 00
Register: 070 Contents: 00
Register: 071 Contents: 00
Register: 072 Contents: 55
Register: 073 Contents: 00
Register: 074 Contents: 00
Register: 075 Contents: 00
Register: 076 Contents: 00
Register: 077 Contents: 00
Register: 078 Contents: 00
Register: 079 Contents: 00
Register: 080 Contents: 00
Register: 081 Contents: 00
Register: 082 Contents: 00
Register: 083 Contents: 07
Register: 084 Contents: 00
Register: 085 Contents: 00
Register: 086 Contents: 00
Register: 087 Contents: 00
Register: 088 Contents: 61
Register: 089 Contents: 11
Register: 090 Contents: 01
Register: 091 Contents: 30
Register: 092 Contents: 00
Register: 093 Contents: 20
Register: 094 Contents: 40
Register: 095 Contents: 10
Register: 096 Contents: 00
Register: 097 Contents: 20
Register: 098 Contents: 00
Register: 099 Contents: 00
Register: 100 Contents: 01
Register: 101 Contents: 01
Register: 102 Contents: 0f
Register: 103 Contents: 03
Register: 104 Contents: 07
Register: 105 Contents: 11
Register: 106 Contents: d9
Register: 107 Contents: d3
Register: 108 Contents: 00
Register: 109 Contents: 00
Register: 110 Contents: 04
Register: 111 Contents: 03
Register: 112 Contents: 81
Register: 113 Contents: 82
Register: 114 Contents: 03
Register: 115 Contents: 00
Register: 116 Contents: 04
Register: 117 Contents: 00
Register: 118 Contents: 85
Register: 119 Contents: 21
Register: 120 Contents: 11


Page 1:

Register: 001 Contents: 00
Register: 002 Contents: 00
Register: 003 Contents: 00
Register: 004 Contents: 03
Register: 005 Contents: 00
Register: 006 Contents: 00
Register: 007 Contents: 00
Register: 008 Contents: 00
Register: 009 Contents: 01


Page 44:

Register: 001 Contents: 04


Page 253:

Register: 126 Contents: 00
Register: 127 Contents: 00

Any help on this would be greatly appreciated, I'm tearing my hair out trying to work out what is going on!

  • Seems 2 of my images failed to load.

    Here is the EQ:

    and here are the eqparameters:

  • In reply to Thomas Cousins:

    Hi Thomas,

    If you configure your clock tree but do not load a custom process flow, does the output work?  The clock tree configuration looks good to me.

    Please try this process flow as a starting point once you confirmed that the PLL is correctly configured.

    PCM5142_I2S_DRC_MB_Int8xROM.pfw

  • In reply to Paul_Frost:

    Hi Paul, thanks for your response,

    Paul_Frost
    If you configure your clock tree but do not load a custom process flow, does the output work?

    Yes, If I set register 43 to 0x01 to select the "8x/4x/2xFIR interpolationfilter with de-emphasis" option the audio works without any problems.

    Paul_Frost
    Please try this process flow as a starting point once you confirmed that the PLL is correctly configured.

    I have loaded this process flow and tried it, but to no avail. There is still no output. I have had to change it to 44.1kHz as that is the only music source I have available at the moment, in this process are there alterations I need to make to the process flow?

    Thanks again,

    Thom

  • Solved it!

    It seems like the parametric EQ and the ROM EQ both do not work on the PCM5142, from another post I found I got the impression that the PEQ is simply too complex to run on the PCM5142 (correct me if I'm wrong Paul?).

    However, the 5-band graphical EQ works fine, for all the rates I'm using apart from 16kHz. This shouldn't be a problem for me but is worth baring in mind for anyone who stumbles across this post in future.

    Above is what worked for me in the end, simple I know. Please ignore the funky EQ values too, I was just wanting to make it clearly audible that it was working, I would never EQ something like this to listen to for pleasure.

  • In reply to Thomas Cousins:

    Good to hear.  Please let me know if you have any other questions.

    Thanks,

    Paul