PCM9211: output noise at MPIO_B3

Wiky Liao

Intellectual 1940 points

Part Number: PCM9211

Hi Team,

We are using PCM9211 in system, and configure MPIO_B port as I2S input port. However, we find that after power on, MPIO_B3 will output some noise, even we remove all of audio source(including other I2S input or AUX in), and the noise is measure at MPIO_B3 pin, and already remove R100. could you help to check this issue and share your comments? thanks.

1. Schematic:

2. noise measure at MPIO_B3

3. PCM9211 register map value:

Reg Value

0x20 0x00

0x21 0x00

0x22 0x01

0x23 0x04

0x24 0x00

0x25 0x01

0x26 0x01

0x27 0x00

0x28 0x03

0x29 0x0C

0x2A 0xFF

0x2B 0xFF

0x2C 0x00

0x2D 0x00

0x2E 0x00

0x2F 0x04

0x30 0x02

0x31 0x1A

0x32 0x22

0x33 0x22

0x34 0xC2

0x35 0x02

0x36 0x02

0x37 0x05

0x38 0x59

0x39 0x80

0x3A 0x00

0x3B 0x00

0x40 0xC0

0x41 0xFF

0x42 0x02

0x43 0x00

0x44 0x00

0x45 0x00

0x46 0xD7

0x47 0xD7

0x48 0x00

0x49 0x00

0x60 0x44

0x61 0x10

0x62 0x00

0x63 0x00

0x64 0x00

0x65 0x00

0x66 0x00

0x67 0x00

0x68 0x00

0x69 0x00

0x6A 0x10

0x6B 0x22

0x6C 0x00

0x6D 0x00

0x6E 0x00

0x6F 0xC0

0x70 0x01

0x71 0x00

0x72 0x00

0x73 0x00

0x74 0x00

0x75 0x00

0x76 0x00

0x77 0x00

0x78 0x00

0x79 0x00

0x7A 0x00

0x7B 0x00

0x7C 0x00

0x7D 0x0E

End

BR.

Wiky

over 6 years ago

0 Steve-Wilson over 6 years ago

TI__Mastermind 30210 points

Hi Wiky,

I will check this out tonight and get back to you before tomorrow evening US time.

best regards,

-Steve Wilson

0 Steve-Wilson over 6 years ago in reply to Steve-Wilson

TI__Mastermind 30210 points

Wiky,

I've copied this configuration you provided and configured the EVM, but I do not see any disturbance on this pin.

are they following good layout guidlines in regards to the FILT circuit and decoupling caps?

best regards,

-Steve Wilson

0 Wiky Liao over 6 years ago in reply to Steve-Wilson

TI__Intellectual 1940 points

Hi Steve,

Thanks for your check on this.

The FILT value is (650R+68nF)||4.7nF, follow by PCM9211 datasheet recommend value.

Could you share an initialize code of PCM9211? Just route from AUX IN to MPIO_B port, we will download it to PCM9211 to check if this issue still exist.

If you have any potential reason for it, please share to us, thanks.

0 Wiky Liao over 6 years ago in reply to Steve-Wilson

TI__Intellectual 1940 points

Hi Steve,

Thanks for your check on this.

The FILT value is (650R+68nF)||4.7nF, follow by PCM9211 datasheet recommend value.

Could you share an initialize code of PCM9211? Just route from AUX IN to MPIO_B port, we will download it to PCM9211 to check if this issue still exist.

If you have any potential reason for it, please share to us, thanks.

0 huaiming tan over 6 years ago in reply to Wiky Liao

Prodigy 60 points

hi TI Team:

We found the root cause is caused by Main Board PCB layout issue, the I2C signal ( layer 3 ) couple to the eARC DATA0 ( layer 4 ), then couple to the Aux input right channel path ( layer 5). then go though to PCM9211 and occurred the dada Noise, not related PCM9211, sorry for bother you and thanks for your supports.

0 Steve-Wilson over 6 years ago in reply to huaiming tan

TI__Mastermind 30210 points

Huaiming tan,

Glad to hear that you have identified the issue. please let us know if there are any other questions you might have regarding the PCM9211

best regards,

-Steve Wilson

Audio

Audio forum

PCM9211: output noise at MPIO_B3