USB Host problems on AT91SAM9G20-EK boards

kamejoko80 · **Joined:** Sat Jun 13, 2009 5:50 pm **Posts:** 43

toplow wrote:

I'm running linux on my 9g20's board,and when I insert the usb sound card or u-disk into 9g20's usb host port,it seems that there are some error information like:
usb 1-1: new full speed USB device using at91_ohci and address 2
usb 1-1: device descriptor read/64, error -71
usb 1-1: device descriptor read/64, error -71
usb 1-1: new full speed USB device using at91_ohci and address 3
usb 1-1: device descriptor read/64, error -71
usb 1-1: device descriptor read/64, error -32
usb 1-1: new full speed USB device using at91_ohci and address 4
usb 1-1: device not accepting address 4, error -71
usb 1-1: new full speed USB device using at91_ohci and address 5
usb 1-1: device not accepting address 5, error -71
hub 1-0:1.0: unable to enumerate USB device on port 1

and sometimes it seems OK,does 9g20's usb host stable?

My at91sam9g20 custom board had the same problem,
When I plug a USB flash disk into Port B, i't works OK. But Port A can not enumerate the USB flash disk as problem above.

gchiii · **Joined:** Fri Jan 22, 2010 4:38 pm **Posts:** 3

how do i get linux to use the sram and DMA for the USB Host controller?

jlehman · **Joined:** Mon May 03, 2010 10:50 pm **Posts:** 2

We are having the same problem. We did not know for a long time since the retry logic was covering the problem. Then we noticed that the USB on the 9G20 was slower and looked at it with an analyzer. We Have Major Jitter problems! Never saw any errors just slower response than another Cirrus arm processor.

We are using the 10uH inductors with 2 caps and a resistor on the VDDPLL and another separate set on the VDDOSC. This has not solved the problem.

Any one solved this? Any ideas?

We have noticed that with the 18.432MHz crystal, the PLLB values which Linux calculates have a -0.15% error. The error allowed for USB is only +/- 0.25%.

ulf · **Posted:** Fri Sep 24, 2010 11:56 pm

jlehman wrote:

We are having the same problem. We did not know for a long time since the retry logic was covering the problem. Then we noticed that the USB on the 9G20 was slower and looked at it with an analyzer. We Have Major Jitter problems! Never saw any errors just slower response than another Cirrus arm processor.

We are using the 10uH inductors with 2 caps and a resistor on the VDDPLL and another separate set on the VDDOSC. This has not solved the problem.

Any one solved this? Any ideas?

We have noticed that with the 18.432MHz crystal, the PLLB values which Linux calculates have a -0.15% error. The error allowed for USB is only +/- 0.25%.

You can use an external crystal oscillator,
instead of a crystal.

ulf · **Posted:** Wed Oct 20, 2010 5:57 pm

One customer has checked the amplitude of the crystal,
and this customer only had 300 mV peak-to-peak.
When running a 3V peak-to-peak sinus signal into the chip,
the USB problems disappear.

davestarkey · **Joined:** Fri Oct 15, 2010 2:54 pm **Posts:** 1

Ok,

Maybe this is my problem too.
My osc voltages are 327mV and 227mV on the crystal. I am running the 18.432Mhz crystal.
I have 10pf load caps to gnd.

What did the customer do to get the voltage up to 3V?

thanks

Dave Starkey

ulf · **Posted:** Thu Oct 21, 2010 6:21 am

davestarkey wrote:

Ok,

Maybe this is my problem too.
My osc voltages are 327mV and 227mV on the crystal. I am running the 18.432Mhz crystal.
I have 10pf load caps to gnd.

What did the customer do to get the voltage up to 3V?

thanks

Dave Starkey

They used a signal generator for the test,
but they are going to put a rystal oscillator there.

Not sure if the small p-p voltage is due to the crystal or the oscillator.
It may be worthwhile to discuss with your crystal manufacturer.

lamination · **Joined:** Tue Jun 07, 2011 2:43 pm **Posts:** 1

Also had problems with USB using crystal with AT91SAM9G20 - resolved by clock generator insted of crystal .

USB Host problems on AT91SAM9G20-EK boards

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