TAS5756M: unstable I2S signal will make TAS5756M's DSP work incorrectly

kidd chen

Part Number: TAS5756M

Hi expert,

There is a USB streaming controller before TAS5756M.
If plug/unplug USB cable repeatedly (=loss MCLK, BCLK, LRCK), TAS5756M will work incorrectly.

The phenomenon is
1. the sound is abnormal loud
2. the frequency response is wrong.

Let the sampling frequency of I2S as 96kHz (higher than the maximum of HF1) can make the same problem too.

My questions are
1. How to detect the problem occurred?
2. How to reset TAS5756M when the problem has been detected?

over 8 years ago

0 Jeff Kohnle over 8 years ago

TI__Expert 6985 points

Hello Kidd! Roy will take a look at your question and get back to you. Thanks, Jeff

0 Jeff Kohnle over 8 years ago in reply to Jeff Kohnle

TI__Expert 6985 points

Hello Kidd! Did you get any feedback on this? Thanks, Jeff

0 kidd chen over 8 years ago in reply to Jeff Kohnle

Prodigy 190 points

Not yet. Please help us.

0 Roy Hsu over 8 years ago in reply to kidd chen

TI__Genius 9390 points

Hi Kidd,

Please check register P0-R91, P0-R93, P0-R94 and P0-R95 to see what are the errors then we'll see how do we clear those errors.

You'll be able to read those registers using PPC2.

Thank you!

Best regards,
-Roy Hsu
Texas Instruments

0 Jeff Kohnle over 8 years ago in reply to Roy Hsu

TI__Expert 6985 points

Hello Kidd! Did this solve you problem? Thanks, Jeff

0 kidd chen over 8 years ago in reply to Jeff Kohnle

Prodigy 190 points

I will check it in this week.

0 kidd chen over 8 years ago in reply to kidd chen

Prodigy 190 points

Hi expert,

I guess the problem is caused by clock auto set.
And I have a project that must use 3-wire PCM (Clock Slave Mode with SLCK PLL to Generate Internal Clocks)

So I want to try 3-wire PCM mode.

First, I load HF1 to make sure the hardware works correctly.
And update those registers.

		//@see page 41 on TAS5756M.pdf
		TAS5756_GotoPage(0);

		TAS5756_WriteRegister(0x04, 1);	//enable PLL

		TAS5756_WriteRegister(0x0D, 0x10);	//set source as SCLK
		//TAS5756_WriteRegister(0x0E, 0x10);	//set source as SCLK

		TAS5756_WriteRegister(0x14, 0x00);	//P=1
		TAS5756_WriteRegister(0x15, 0x10);	//J
		TAS5756_WriteRegister(0x16, 0x00);	//D (MSB)
		TAS5756_WriteRegister(0x17, 0x00);	//D	(LSB)
		TAS5756_WriteRegister(0x18, 0x01);	//R

		TAS5756_WriteRegister(0x1B, 0x01);	//NMAC
		TAS5756_WriteRegister(0x1C, 0x0F);	//DDAC
		TAS5756_WriteRegister(0x1D, 0x03);	//DNCP
		TAS5756_WriteRegister(0x1E, 0x07);	//DOSR

		TAS5756_WriteRegister(0x22, 0x00);	//FS speed
		TAS5756_WriteRegister(0x23, 0x04);	//IDAC(MSB)
		TAS5756_WriteRegister(0x24, 0x00);	//IDAC(LSB)
		TAS5756_WriteRegister(0x25, 0x02);	//disable clock auto set

My question is

I can't set P0-R28 in PPC. Should I configure it?
drive.google.com/open
drive.google.com/open
After changing those registers, TAS5756 can make sounds.
However, if I short the MCLK pin and GROUND, there is no sound.
R94=0x40 (MCLK is missing)
What should I do?
this is the register dump of page0.
https://drive.google.com/open?id=0B6dUa8IkGvZ3LTFhR2J5R2hqSVU

0 kidd chen over 8 years ago in reply to kidd chen

Prodigy 190 points

I revolve the both issues by myself.
1) unstable I2S signal will make TAS5756M's DSP work incorrectly <- use 3-wire PCM mode
2) 3-wire PCM mode <- I can use 3-wire PCM mode now.

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TAS5756M: unstable I2S signal will make TAS5756M's DSP work incorrectly