Using USB with OMAP L-137

Hi,

   You might have to plug in the USB drive first and then run the program. I have run the program on my side and it works with my USB flash. What specific USB drive did you try? I also suggest you try a small size USB flash instead of a USB hard drive to eliminate any potential power problem. If it still does not work, the problem may have something to do with your EVM board.

Hi,

Thanks for your anwser. I did plug the USB drive before running the program.

I've tried these two USB drives:

- Kingston DataTraveler 101 G2 (4 GB)

- DEONET USB stick (1 GB)

Hi,

    I have noticed a little difference between your setup and mine. I am using EDMALLD_01.11.00.03 and ERTFS_1_10_00_30. I have verified it with Kinston Data Traveler G2 (4GB). It works with my setup.

Hi,

I've installed  EDMA LLD 01.11.00.03 and RTFS 1.10.00.30. I still have the same problem, mostly. I've tried to run the program a lot of times and for the most part, it didn't work. However, it did work twice, but I absolutely don't know why.

Here's what is displayed when the program didn't work;
when the USB drive is in the USB 2.0 port:

USB Application Task 0 Starting
Initializing usb host stack
ohci_local0: OHCI version 1.0
ohci_local0: USB revision 1.0
ohci_local0: new device port=0 depth=0 speed=full
uhub0 Jungo Generic Root Hub, class 9/0, rev 0.11/af.00, addr 1
uhub0: 2 ports with 2 removable, self powered
musbhshc0: USB revision 2.0
musbhshc0: new device port=0 depth=0 speed=high
uhub1 Jungo Generic Root Hub, class 9/0, rev 0.20/af.00, addr 1
uhub1: 1 port with 1 removable, self powered
 polling for storage media
uhub0: new device port=1 depth=1 speed=full
 polling for storage media
uhub0: device problem, disabling port 1
 polling for storage media
 polling for storage media
USB Device Not available

and when the USB drive is in the USB 1.0 port:

USB Application Task 0 Starting
Initializing usb host stack
ohci_local0: OHCI version 1.0
ohci_local0: USB revision 1.0
ohci_local0: new device port=0 depth=0 speed=full
uhub0 Jungo Generic Root Hub, class 9/0, rev 0.11/af.00, addr 1
uhub0: 2 ports with 2 removable, self powered
musbhshc0: USB revision 2.0
musbhshc0: new device port=0 depth=0 speed=high
uhub1 Jungo Generic Root Hub, class 9/0, rev 0.20/af.00, addr 1
uhub1: 1 port with 1 removable, self powered
 polling for storage media
 polling for storage media
 polling for storage media
 polling for storage media
USB Device Not available

I can't figure out why the program worked only twice and not the other times, because I don't think I've done anything differently those two times. This is really confusing.

I don't know if it is relevant, but there's a LED on the USB drive which is lit when I first plug the drive into the USB port. When I ran the program and it didn't work, that LED would turn off at some point and stay off.
When the USB drive is in the 2.0 port, the LED turns off when the "uhub0: device problem, disabling port 1" line is displayed. When the USB drive is in the 1.0 port, that happens much earlier.

Hi,

Can you pl. ensure that the USB miniA-A adapter is plugged in to the usb connector (either with or without the device) before you power on the EVM?

Also can you ensure that the usb mini-A-A adapter is working correctly.

regards

swami

Hi,

On the custom board I'm using, the two USB ports are standard type A, so I wasn't using an adapter.

However, I have now tested the code on the evaluation board (OMAP-L137 EVM) and it works perfectly.
So, because the code works sometimes (but rarely) on our custom board, we think it's a problem with the initialization. Do you know what parts of the USB example program are specific to the EVM board, and would have to be changed for a custom board?

Thanks.

Hi,

Can you confirm that you have grounded the ID line (as per usb spec).  USB type A connector does not have a ID line and hence it is possible that you might have left the line floaing in your custom board, if so this might be the reason for the usb not to detect the usb stick.

regards

swami

Hi,

The USB0_ID pin is connected to ground via a 0 ohm resistor.

When you mentioned that the led on the usb stick turns on when you connect the drive can you confirm that this hapens every time you power on the evm or everytime you connect the usb stick to the evm?

regards

swami

Hi,

The LED on the USB stick turns on every time it is connected to the board (if the board is powered). It is normal for that USB stick to stay lit as long as it is connected to a host.
The LED only turns off when I run the program. After that, the LED will only turn on again if I unplug the stick then plug it again, or if I turn off the board then turn it on again.

Hi,

It seems that the USB VBUS power on your evm may not be sufficient to power the usb device.  Can you verify whether the VBUS power is adequate to meet the power needs of the connected usb stick.

Typically 500ma at 5V would be needed for a host operation.

regards

swami

Hi,

I have measured the voltage and current, I do have 5V and 500 mA on both VBUS pins.