Problem with connecting PCM2707 to USb

[kiranp]

Hi,

I have rigged up a circuit which is used for USB to I2s conversion..
I am using PCM2707 IC from Texas instruments...

And i have attached the schematic of my board also.. I am facing problems in making it recognized , meant to say that when i connect the PCB onto USB port.. A message pops up on windows saying USB not recognized...

I dont know what fault is in my Schematic.. I cross checked the wiring , the components many times .. but didn't find any mistakes..

Can anyone please guide me in getting the work done...

Thank you,
Kitty

 

[lakeside]

I believe pin 3 (HOST) should have a connection to Vcc.

~Mike

 

[kiranp]

I believe pin 3 (HOST) should have a connection to Vcc.

Some designs have it connected to VCC and some to ground.. I tried both combinations but didnt work

 

[rrrremus]

Take a look on the configuration i use for PCM2706.

An externally hosted image should be here but it was not working when we last tested it.

Uploaded with ImageShack.us

 

[kiranp]

Take a look on the configuration i use for PCM2706.

Thanks for the circuit... But i don find much changes in yours and mine.. Mine is Bus powered and yours is Self powered.

Then you have connected all the Analog Vcc's to 3.3V and i have connected to ground.. I think , this will not be of much concern..

But whats that AND gate doing with that HOST pin???

 

[rrrremus]

The gate is there to prevent HOST detection while the DAC is powered off; the chip can be configured to run bus-powered.
Does your PCM2707 chip oscillate ? Is your USB connector wired correctly ?

 

[kiranp]

Does your PCM2707 chip oscillate ? Is your USB connector wired correctly ?

U meant does the 12Mhz oscillate ?? i checked with an CRO for it i got a near 12MHz oscillation..

USB is wired correctly , is there anyway to check whether PCM is dead or working??

 

[rrrremus]

Yes, i mean if the 12MHz oscillates. The 1M ohm resistor and ~27pF capacitors are critical, the chip will not work without them, even if you see oscillation. Show us a photo of your PCB, maybe we can spot something.

 

[kiranp]

Yes, i mean if the 12MHz oscillates. The 1M ohm resistor and ~27pF capacitors are critical, the chip will not work without them, even if you see oscillation. Show us a photo of your PCB, maybe we can spot something.

I am onto it as a prototype , so my PCB is still on its way... i have a not so good picture of it , but i don think you will be able to track the lines and all sorry....

 

[rrrremus]

That looks nasty. Build a PCB for it.

 

[kiranp]

Successsssss!!!!!!!!!!!

I am able to get the PCM detected..

All the pull ups which were given to 5V were given to 3.3V.. I used a 5 to 3.3V regulator and it worked...

It detects as an USB Audio device...

This comes up in the Control Panel => Sounds and devices..

But when i connect my I2S output lines to a Transmitter which has the I2S inputs m not able to receive any audio...

Is there anyway i can verify that audio is been streamed through PCM???

 

[kiranp]

Whats the format of the I2S out ???

Is it ----

Standard I2S
Left Justified (16, 18, 20 or 24 bits)
16 bits Right Justified
18 bits Right Justified
20 bits Right Justified
24 bits Right Justified

Please do guide me???

 

[rrrremus]

What exactly is this 'transmitter' you are using ?
I connect the PCM to a sample rate converter, i never tested the analog outputs or other functions of the chip. But you might want to test if your chip's analog outputs are working.

 

[kiranp]

What exactly is this 'transmitter' you are using ?

I cant name it but it has I2S , analog and SPDIF inputs.. Atleast i i can verify that the analog out is working then it would be fine i think..

But you might want to test if your chip's analog outputs are working.

Yes i want to do this , what all changes should i make... is only VoutR and VoutL enough??? should i pull up all the Vcc R,L,P to 3.3V???

 

[rrrremus]

You should read the datasheet again carefully.
First of all, you must make sure that the FSEL pin is low for I2S output. Otherwise SPDIF output is selected.
I think the audio analog outputs are always active.

 

[kiranp]

When i connect my module to USB port , it is detected as a USB Audio device and falls under " Sound, video and game controllers " in the device manager..

I checked the Frequency on I2S lines ,

SCLK = 12.20 to 12.31 MHz
LRCLK = 48 KHz
Bit CLK = 2.8 MHz

Is there anywhere i am wrong , please do correct me...