S/PDIF sampling frequency calculation of PCM9211

ttd

Mastermind 7660 points

Other Parts Discussed in Thread: PCM9211

Dear technical support team,

I have a question about DIR of PCM9211.

Checking 0x39 for LOCK/UNLOCK and input Fs of DIR.

When S/PDIF input（LPCM44.1kHz）, 0x39 shows variation like 0x08 and 0x88.

This shows both 44.1kHz sampling and during frequency calculation .

It cause once in about 10 power-on.

Following is other status.

・ERROR pin and NPCM pin always show "low".

・If remove the cable for causing unlock status and connect cable again, 0x39 shows 0x08 and stable.

・If hard reset(RST pin) or soft reset assert while 0x39 shows 0x88 and set register again, 0x39 shows 0x08 and stable.

・Using 24.576MHz XTI

・Register setting is following

Reg 0x20：0x00

Reg 0x23：0x00

Reg 0x24：0x80

Reg 0x25：0x29

Reg 0x26：0x00

Reg 0x28：0x07

Reg 0x2A：0x7F

Reg 0x30：0x10

Reg 0x31：0x0A

Reg 0x34：0xC2

Reg 0x40：0xE2

Reg 0x6B：0x11

Best Regards,

y.i

over 7 years ago

0 Justin Bohr over 7 years ago

TI__Mastermind 27850 points

Hi Y.i,

I'm not entirely sure what you are asking. Is your question about what the frequency rate register is reporting? Are you observing the reported rate as being incorrect?

Justin

0 ttd over 7 years ago in reply to Justin Bohr

Mastermind 7660 points

Hi Justin,

Thank you for your reply.
I'd like to ask the meaning of the reported 39h = 0x88(SFSST="1" and SFSOUT[3:0] ="1000").
I think that correct behavior of 44.1kHz always shows 39h = 0x08(SFSST="0" and SFSOUT[3:0] ="1000").

Best Regards,
y.i

0 Justin Bohr over 7 years ago in reply to ttd

TI__Mastermind 27850 points

Hi y.i,

When SFSST = 1 the calculator is in the process of calculating the frequency of the incoming SPDIF signal, or is unable to calculate the frequency due to loss of lock. So when the device has calcuated the sampling frequency, SFSST will be 0.

Justin

Audio

Audio forum

S/PDIF sampling frequency calculation of PCM9211