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Original question:

Problem in using TPS65950 Audio part

DM3730: TPS65950 codic audio output has noise occasionally

Jerome Xiong
Prodigy 40 points
Part Number: DM3730
Other Parts Discussed in Thread: TPS65950, , SYSCONFIG

We meet a sound problem on LogicPD's SOM DM3730 with CODEC TPS65950.  It has a sound bug during pilot test: our device sound outpu becomes abnormal occasionally. Noise will not automatically dissapear until tune off the power. If you repeatedly turn on and off the power about 1/30 chance the abnormal noise will come again. 

We cut off the back stage and tested the TPS65950 output wave form when device play a 500Hz sine sound file. 

 

Figure 1 abnormal sound wave

 While the normal wave on other device is bellowing, no high frequency noise.

Figure 2 . normal wave

 

Then we use logic analyzer sampled the I2S data in TP2 and found when sound abnormal , data is ok!

Figure 3  data collected from I2S when audio abnormal

We collecected the audio wave and do FFT in Matlab to find the noise freq is about 7KHz


Figure 4 FFT result when sound abnormal

Also we can compare the normal one, no 7K componets:


Figure 5 FFT result when normal, only 500Hz and it's hamonical components.

In order to locate the problem, we have tried 2 changes by software modification. one is change the audio sorce sample rate from 8K to 16K. Then the occasion sound abnormal became always abnormal.  We assume there may be some registers configure wrong. But we check it is by read back all the regs value it is the same with another normal device.

Another try is add a manually reset button to reconfigure all the regs when sound abnormal. And it works. 

Now I am woundering what cause the 7K occasional noise. And what solusion to prevent the abnormal happen since we can't put an extra reset button in our system. So please help and analysis this case, Thank you!

 

  • 0
    TI__Guru**** 170625 points

    Hi Jerome,

    I would suggest you to measure with scope DM37x McBSP pins and check if you will have the correct and expected signals there. You can also dump McBSP registers and check if error logs will appear. You need to isolate the issue, it can be in DM37x McBSP module or in your audio codec. In case the issue is in the audio codec, you need to ask/post in the Audio forum:

    For DM37x detailed SW support, you can reach out to one of the following third parties:

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    Prodigy 40 points

    I captured the MCBSP2 pin data, no waveform and timing issue found.

    Then I ask SW engnieer print out registers both abnormal and normal, then we found they are the same:

    mcbsp clock config:
    1. CM_FCLKEN_PER,address:48005000,value:7ffff
    2. CM_ICLKEN_PER,address:48005010,value:7ffff
    3. CONTROL_DEVCONF0,address:48002274,value:5000040
    4. MCBSP2_PCR0_REG,address:49022048,value:f
    5. MCBSP2_SRGR2_REG,address:49022028,value:301f
    6. CM_IDLEST_PER,address:48005020,value:0
    7. MCBSP2_SPCR1_REG,address:49022014,value:0
    8. MCBSP2_SPCR2_REG,address:49022010,value:207
    9. MCBSP2_XCR1_REG,address:49022024,value:40
    10. MCBSP2_IRQSTATUS_REG,address:490220a0,value:4f02
    11. MCBSP2_XCR2_REG,address:49022020,value:8041
    12. MCBSP2_RCR1_REG,address:4902201c,value:40
    13. MCBSP2_RCR2_REG,address:49022018,value:8041
    14. MCBSP2_SRGR1_REG,address:4902202c,value:fff
    15. MCBSP2_MCR1_REG,address:49022034,value:0
    16. MCBSP2_MCR2_REG,address:49022030,value:0
    17. MCBSP2_RCERA_REG,address:49022038,value:0
    18. MCBSP2_RCERB_REG,address:4902203c,value:0
    19. MCBSP2_XCERA_REG,address:49022040,value:0
    20. MCBSP2_XCERB_REG,address:49022044,value:0
    21. MCBSP2_REV_REG,address:4902207c,value:23
    22. MCBSP2_RINTCLR_REG,address:49022080,value:0
    23. MCBSP2_XINTCLR_REG,address:49022084,value:0
    24. MCBSP2_ROVFLCLR_REG,address:49022088,value:0
    25. MCBSP2_SYSCONFIG_REG,address:4902208c,value:0
    26. MCBSP2_THRSH2_REG,address:49022090,value:0
    27. MCBSP2_THRSH1_REG,address:49022094,value:0
    28. MCBSP2_IRQENABLE_REG,address:490220a4,value:0
    29. MCBSP2_WAKEUPEN_REG,address:490220a8,value:0
    30. MCBSP2_XCCR_REG,address:490220ac,value:0
    31. MCBSP2_RCCR_REG,address:490220b0,value:0
    32. MCBSP2_XBUFFSTAT_REG,address:490220b4,value:305
    33. MCBSP2_RBUFFSTAT_REG,address:490220b8,value:0
    codec config:
    1. TRITON2_ATXL1PGA_OFFSET,address:a,value:0
    2. TRITON2_ATXR1PGA_OFFSET,address:b,value:0
    3. TRITON2_ARXR1PGA_OFFSET,address:10,value:3f
    4. TRITON2_ARXL1PGA_OFFSET,address:11,value:3f
    5. TRITON2_ARXR2PGA_OFFSET,address:12,value:3f
    6. TRITON2_ARXL2PGA_OFFSET,address:13,value:3f
    7. TRITON2_AVTXL2PGA_OFFSET,address:c,value:0
    8. TRITON2_AVTXR2PGA_OFFSET,address:d,value:0
    9. TRITON2_VRXPGA_OFFSET,address:14,value:0
    10. TRITON2_ARXL1_APGA_CTL_OFFSET,address:19,value:b
    11. TRITON2_ARXR1_APGA_CTL_OFFSET,address:1a,value:b
    12. TRITON2_ARXL2_APGA_CTL_OFFSET,address:1b,value:b
    13. TRITON2_ARXR2_APGA_CTL_OFFSET,address:1c,value:b
    14. TRITON2_BTPGA_OFFSET,address:1f,value:0
    15. TRITON2_ALC_CTL_OFFSET,address:2b,value:0
    16. TRITON2_DTMF_FREQSEL_OFFSET,address:30,value:0
    17. TRITON2_DTMF_TONOFF_OFFSET,address:35,value:0
    18. TRITON2_DTMF_WANONOFF_OFFSET,address:36,value:0
    19. TRITON2_APLL_CTL_OFFSET,address:3a,value:16
    20. TRITON2_DTMF_PGA_CTL2_OFFSET,address:3c,value:0
    21. TRITON2_DTMF_PGA_CTL1_OFFSET,address:3d,value:0
    22. TRITON2_VDL_APGA_CTL_OFFSET,address:44,value:0
    23. TRITON2_RX_PATH_SEL_OFFSET,address:43,value:30 

    I also try to manual reset all regesisters when audio abnormal. After reset, there are some difference:

    mcbsp clock config:

    1. CM_FCLKEN_PER,address:48005000,value:7ffff
    2. CM_ICLKEN_PER,address:48005010,value:7ffff
    3. CONTROL_DEVCONF0,address:48002274,value:5000040
    4. MCBSP2_PCR0_REG,address:49022048,value:f
    5. MCBSP2_SRGR2_REG,address:49022028,value:301f
    6. CM_IDLEST_PER,address:48005020,value:0
    7. MCBSP2_SPCR1_REG,address:49022014,value:0
    8. MCBSP2_SPCR2_REG,address:49022010,value:20f
    9. MCBSP2_XCR1_REG,address:49022024,value:40
    10. MCBSP2_IRQSTATUS_REG,address:490220a0,value:4f82
    11. MCBSP2_XCR2_REG,address:49022020,value:8041
    12. MCBSP2_RCR1_REG,address:4902201c,value:40
    13. MCBSP2_RCR2_REG,address:49022018,value:8041
    14. MCBSP2_SRGR1_REG,address:4902202c,value:fff
    15. MCBSP2_MCR1_REG,address:49022034,value:0
    16. MCBSP2_MCR2_REG,address:49022030,value:0
    17. MCBSP2_RCERA_REG,address:49022038,value:0
    18. MCBSP2_RCERB_REG,address:4902203c,value:0
    19. MCBSP2_XCERA_REG,address:49022040,value:0
    20. MCBSP2_XCERB_REG,address:49022044,value:0
    21. MCBSP2_REV_REG,address:4902207c,value:23
    22. MCBSP2_RINTCLR_REG,address:49022080,value:0
    23. MCBSP2_XINTCLR_REG,address:49022084,value:0
    24. MCBSP2_ROVFLCLR_REG,address:49022088,value:0
    25. MCBSP2_SYSCONFIG_REG,address:4902208c,value:0
    26. MCBSP2_THRSH2_REG,address:49022090,value:0
    27. MCBSP2_THRSH1_REG,address:49022094,value:0
    28. MCBSP2_IRQENABLE_REG,address:490220a4,value:0
    29. MCBSP2_WAKEUPEN_REG,address:490220a8,value:0
    30. MCBSP2_XCCR_REG,address:490220ac,value:0
    31. MCBSP2_RCCR_REG,address:490220b0,value:0
    32. MCBSP2_XBUFFSTAT_REG,address:490220b4,value:2fd
    33. MCBSP2_RBUFFSTAT_REG,address:490220b8,value:0

    codec config:
    1. TRITON2_ATXL1PGA_OFFSET,address:a,value:0
    2. TRITON2_ATXR1PGA_OFFSET,address:b,value:0
    3. TRITON2_ARXR1PGA_OFFSET,address:10,value:3f
    4. TRITON2_ARXL1PGA_OFFSET,address:11,value:3f
    5. TRITON2_ARXR2PGA_OFFSET,address:12,value:3f
    6. TRITON2_ARXL2PGA_OFFSET,address:13,value:3f
    7. TRITON2_AVTXL2PGA_OFFSET,address:c,value:0
    8. TRITON2_AVTXR2PGA_OFFSET,address:d,value:0
    9. TRITON2_VRXPGA_OFFSET,address:14,value:0
    10. TRITON2_ARXL1_APGA_CTL_OFFSET,address:19,value:b
    11. TRITON2_ARXR1_APGA_CTL_OFFSET,address:1a,value:b
    12. TRITON2_ARXL2_APGA_CTL_OFFSET,address:1b,value:b
    13. TRITON2_ARXR2_APGA_CTL_OFFSET,address:1c,value:b
    14. TRITON2_BTPGA_OFFSET,address:1f,value:0
    15. TRITON2_ALC_CTL_OFFSET,address:2b,value:0
    16. TRITON2_DTMF_FREQSEL_OFFSET,address:30,value:0
    17. TRITON2_DTMF_TONOFF_OFFSET,address:35,value:0
    18. TRITON2_DTMF_WANONOFF_OFFSET,address:36,value:0
    19. TRITON2_APLL_CTL_OFFSET,address:3a,value:16
    20. TRITON2_DTMF_PGA_CTL2_OFFSET,address:3c,value:0
    21. TRITON2_DTMF_PGA_CTL1_OFFSET,address:3d,value:0
    22. TRITON2_VDL_APGA_CTL_OFFSET,address:44,value:0
    23. TRITON2_RX_PATH_SEL_OFFSET,address:43,value:30 

    But I think it is causd by reset, not mean to MCBSP configure error.  Curretly I can't fully locate the issue. now that no error in regisiters redback, it seems codec has more suspicion point.

  • 0 in reply to Pavel Botev
    Prodigy 40 points

    Today I tried to only re-configure MCBSP when audio abnormal, but after reset audio still abnormal. So problem should be in codec. Please help to move to audio forum, thanks.

  • 0 in reply to Jerome Xiong
    TI__Guru**** 170625 points

    Jerome,

    In case the issue is in the audio codec, you can open new e2e thread in the Audio forum:

    Regards,
    Pavel