4 MHz USB issue

julien239955_stm1 · ‎2005-11-17

Posted on November 17, 2005 at 13:29

4 MHz USB issue

julien239955_stm1 · ‎2005-11-16

Posted on November 17, 2005 at 05:08

Hi,

I've been developping the usb part of our client's application on the eval board. Everything works fine on the eval board.

The application is really simple, I just have 2 leds blinking all the time and managemant of the usb when the cable is plugged.

I have migrated the application on our clients hardware, which uses the 4Mhz HCLK input plus the PLL2 to clock the USB.

The main difference is that on our client's hardware, once the interrupts are enabled, I have the WAKE_UP interrupt which occurs all the time, so the application hangs.

Once I plug the usb cable, the application starts correctly and my leds are blinking.

One solution would be to mask the wake up interrupt until the bus reset, but I don't see why it happens on the client's hardware, and not on the eval board.

Anyone has any idea?

Thanks

Julien

mohamed23 · ‎2005-11-17

Posted on November 17, 2005 at 09:12

Hi ruliano,

It is a strange behavior, Could you use Two probes

on DP and DM and capture with an Oscilloscope the sequence before and after the plug of any usb cable.

The hardware you are using (USB part) is the same as the Eval Board or not ?

Regards,

:o

[ This message was edited by: Rave on 17-11-2005 13:43 ]

julien239955_stm1 · ‎2005-11-17

Posted on November 17, 2005 at 13:29

For sure this is a strange problem,

I haven't looked at DP and DM yet, but I kind of feel like there is something noisy around, which gives these unexpected interrupts.

The USB hardware is the same as the one on the MB393 eval board, except the 0 Ohms resistors on DP and DM after the USBUF01WG, and the connector, which is not a USB B plug, but a specific one (RJ45). So the usb cable I have has an A plug on one side and an RJ45 plug on the other side..

The thing is I haven't developped the hardware, so I don't know if there is something noisy or not.

I have been able to make my application start correctly by masking the WAKE_UP interrupt as long as the usb cable has not been plugged, and unmask it when the cable is plugged. I can then pass the enumeration process, and transfer data, but as soon as I unplug the cable, the application stucks again.

Anyone had the same kind of issue?

Thanks

Julien