I'm trying to make a PCM2902 USB sound card, using the (almost exact) schematic from the data sheet. Made a PCB, all connections are correct (as far as I can see) and there are no shorts. But, when I connect the device, Windows won't recognize it. I keep getting the message that there is a USB device connected, but it is not recognized.
You can find the schematic in the data sheet.
The PCB I made is attached, with and without silk screen. Does it matter that I used electrolytic capacitors instead of non-polars for the 1uFs? I replaced both ICs and it still doesn't work. There is a fine 5V USB voltage on the chip, but the !SSPND pin doesn't get high. I can't measure the crystal's signal, since I have no scope at hand. Is this very critical to layout?
Thanks in advance.
You can find the schematic in the data sheet.
The PCB I made is attached, with and without silk screen. Does it matter that I used electrolytic capacitors instead of non-polars for the 1uFs? I replaced both ICs and it still doesn't work. There is a fine 5V USB voltage on the chip, but the !SSPND pin doesn't get high. I can't measure the crystal's signal, since I have no scope at hand. Is this very critical to layout?
Thanks in advance.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Hmm, I can't edit the above post...
But, I just saw I didn't connect SEL1 and SEL0 to the positive supply voltage. But, even after doing that, it doesn't get recognized.
But, I just saw I didn't connect SEL1 and SEL0 to the positive supply voltage. But, even after doing that, it doesn't get recognized.
i feel you need to swap the data pins probably you have mixed those up.. that why its not getting reconz.. i had some thing like lthis when i was fixing my mp3 player data cable and i had mixed up piins.. i am talking of the data + and data - pins not + vcc and ground... mind it.
Hello Limhes,
check if your oscillator is working.
If not, try different values for the capacitors near the crystal.
You need a scope to see if the oscillator is working properly!
Andreas
check if your oscillator is working.
If not, try different values for the capacitors near the crystal.
You need a scope to see if the oscillator is working properly!
Andreas
The 1Mohm resistor in parallel with the crystal has to be there.
I left this out on a PCM2906 design, it would detect as a USB device in this case but wouldn't go any farther, same as what you're seeing.
I left this out on a PCM2906 design, it would detect as a USB device in this case but wouldn't go any farther, same as what you're seeing.
For the record. Electrolytic caps can be used with no problem. Even the modest Nichicon Muse FW. 🙂 I suggest 10uF would do the job. I didn't say it is the best to use electrolytic though.
Some reports that after pull in/out for a while, this guy might just wake up and work at anytime.
As I can't see the posted pictures, I can't comment.
Some reports that after pull in/out for a while, this guy might just wake up and work at anytime.
As I can't see the posted pictures, I can't comment.
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