USB controller problems on DAC?

excetara2 · 19th September 2006, 06:52 AM

I have a DDDAC board that has a PCM2707PJT and I am using the built in D/A converter. My usb part stop being reconized. If I plug it in the icon comes up but says unrecognized device. If this happnes again, replace device. In advice on what I can do. Thanks.

excetara2 · 19th September 2006, 08:52 PM

Anybode no anything about the PCM2707 controller. Why it would malfucntion like this?

jkeny · 19th September 2006, 09:36 PM

Did it work at one time? This seems to be a problem with this chip. Do a search on this forum for PCM2706/7 to see posts about this.

John

FastEddy · 19th September 2006, 10:16 PM

http://focus.ti.com/docs/prod/folder...t/pcm2707.html

excetara2 · 20th September 2006, 12:14 AM

Thanks. I noticed something. I don't get any voltage on Vcom. Should I get voltage here? I don't get 3.3V either unless I plug in external power from battery. I get like 2.6V.

excetara2 · 20th September 2006, 06:13 AM

What exactly is Vcom for? I have been reading over the data sheet and it says analog input voltage. Is this correct. It has VoutL and VoutR under analog input voltage.

jkeny · 20th September 2006, 02:10 PM

Yes you should get 3.3V on Vcom AFAIK. I think it is the PS for analogue out. What do you mean you have to plug in external power? Are u not powering this off uSB - if not give us the details.

JOhn

excetara2 · 20th September 2006, 02:26 PM

Here is a schematic. Ended up showing up really crappy because resizing. I will post elsewhere later.

FastEddy · 20th September 2006, 03:33 PM

... VCOM shows not connected in your drawing ...

No idea what it is for without careful examination of chip specs, etc. ...

excetara2 · 20th September 2006, 04:58 PM

That was bad when I tried to reduce it to meat the specifications of 1000X1000 the pixels got messed up. Here is the photo :

19th September 2006, 06:52 AM	#1
excetara2 diyAudio Member Join Date: Jun 2006	USB controller problems on DAC? I have a DDDAC board that has a PCM2707PJT and I am using the built in D/A converter. My usb part stop being reconized. If I plug it in the icon comes up but says unrecognized device. If this happnes again, replace device. In advice on what I can do. Thanks.

19th September 2006, 10:16 PM	#4
FastEddy diyAudio Member Join Date: Jun 2006 Location: North Californie	check this too ... http://focus.ti.com/docs/prod/folder...t/pcm2707.html

20th September 2006, 03:33 PM	#9
FastEddy diyAudio Member Join Date: Jun 2006 Location: North Californie	no connect? ... VCOM shows not connected in your drawing ... No idea what it is for without careful examination of chip specs, etc. ...

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19th September 2006, 08:52 PM	#2
excetara2 diyAudio Member Join Date: Jun 2006	Anybode no anything about the PCM2707 controller. Why it would malfucntion like this?

19th September 2006, 09:36 PM	#3
jkeny Banned Join Date: Feb 2007 Location: Dublin	Did it work at one time? This seems to be a problem with this chip. Do a search on this forum for PCM2706/7 to see posts about this. John

20th September 2006, 12:14 AM	#5
excetara2 diyAudio Member Join Date: Jun 2006	Thanks. I noticed something. I don't get any voltage on Vcom. Should I get voltage here? I don't get 3.3V either unless I plug in external power from battery. I get like 2.6V.

20th September 2006, 06:13 AM	#6
excetara2 diyAudio Member Join Date: Jun 2006	What exactly is Vcom for? I have been reading over the data sheet and it says analog input voltage. Is this correct. It has VoutL and VoutR under analog input voltage.

20th September 2006, 02:10 PM	#7
jkeny Banned Join Date: Feb 2007 Location: Dublin	Yes you should get 3.3V on Vcom AFAIK. I think it is the PS for analogue out. What do you mean you have to plug in external power? Are u not powering this off uSB - if not give us the details. JOhn

20th September 2006, 04:58 PM	#10
excetara2 diyAudio Member Join Date: Jun 2006	That was bad when I tried to reduce it to meat the specifications of 1000X1000 the pixels got messed up. Here is the photo :

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