Hi,
I am using HOST drivers provided by TI for USB host application for LM3S3749 controller. I am trying to connect a USB device to the USB host. The setup is working fine when using LM3S3748 EVK. But when i come to board with LM3S3749 controller, it is giving VBUS Error interrupt.
The difference in the LM3S3748 EVK and board with LM3S3749 is:
1) USB0EPEN and USB0PFLT are directly connected to ground without any resistor.
2) VBUS (+5V) is directly connect to the USB host connector without any regulartor as in LM3S3748 EVK.
Do i need to make any changes in the USB host code for the above said hardware changes.
Even without connecting a device to the USB HOST, the VBUS error intrrput is coming.
Pradip,
If you are tying USB0EPEN and USB0PFLT to ground, you should not be configuring these pins to be driven by the USB controller. You might check that their AFSEL bits are off.
But these pins should not cause the VBUS error. This should require that VBUS drop from above 5V to ~4.75V. The first thing to do here is to look at the VBUS pin on a scope to verify it is consistently valid.
KC Witte
Hi Kendall,
Thanks for the reply.
Yes, Voltage at VBUS pin was varying and dropping below 4.75 V. The problem is solved by providing VBUS > 4.75 V