Hi,
1. May I know what is the use of the USB_OTG_VBUS pin of iMX53? Should this pin be tied to the External 5V USB power?
2. And how about the VBUS pin of the MC34708 PMIC? It is described as I/O pin for "USB transceiver cable interface VBUS & OTG supply output" in the Datasheet. Should this pin be tied to the External 5V USB power as well?
3. Does anyone encounter "USB Device Not Recognized" upon connecting the iMX53 to a Computer? When this happens, it will be shown as Unknown device in the Device Manager. But sometimes it does work as per normal though.
Thanks & regards,
Eric
Hi Eric
please look at reference schematic for connection USB_OTG_VBUS
MCIMX53-START-R i.MX53 QS Board Schematics 
:
i.MX53 Quick Start board with MC34708
for VBUS PMIC usage one can check datasheet MC34708
"USB Device Not Recognized" means that smth wrong with software,
running on that board. Also that may be caused by long USB cable,
noise or weak usb signal.
Best regards
igor
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Hello igor,
Thanks for your reply.
Yes. I did refer to the Schematic of i.MX53 Quick Start board with MC34708. I did also refer to the i.MX53 System Development User's Guide for reference. According to the latter, it is recommended to use a series 47ohm resistor with a 1uF cap at the VBUS.
The QSB is using a ferrite bead instead. Is this going to be okay?
As for the PMIC VBUS, I did check on the datasheet but it is not clearly explained the function of this pin and how it should be connected.
Thanks.
Eric
Hi,
I am experiencing the following problem right now.
I did try to update the driver but it does not help.
Is there anyone who can help on this?
Regards,
Eric
