iMX35 - USB Hard disk support

HK · ‎10-01-2009

I am trying to connect a USB portable hard disk that is being formatted as a FAT32 filesystem to a i.MX35 (PDK 1.5) board that was booted with WinCE 6.0. But the hard disk is not being recognized. I have built the BSP with all the required USB host functions. I tried a FAT32 formatted USB (2.0) flash drive and a USB card reader with SD (as well as CF) card, and they all work fine. The board was able to recognize the flash drive and the card reader but not the HD. Has anyone seen a similar problem? Any help would be much appreciated!

kschumm · ‎10-01-2009

I don't know anything about wince, but we tried USB hard drives on another product of ours and discovered a couple of things to check. First, if the drive is port powered make sure it doesn't exceed the USB port power that is available. Second, it seems that sometimes hard drives seem slow to enumerate. Maybe they don't enumerate until they spin up and by that time the enumeration process has failed from the host perspective. We found that USB micro-drives generally worked and the full size drives in external housings often failed. YMMV.

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HK · ‎10-01-2009

Thanks for the reply! Actually, yes, power was the problem. I tried an external hard disk and that worked fine. You are right. I think the portable hard disk I was using was exceeding the USB port power.

kschumm · ‎10-01-2009

I don't know anything about wince, but we tried USB hard drives on another product of ours and discovered a couple of things to check. First, if the drive is port powered make sure it doesn't exceed the USB port power that is available. Second, it seems that sometimes hard drives seem slow to enumerate. Maybe they don't enumerate until they spin up and by that time the enumeration process has failed from the host perspective. We found that USB micro-drives generally worked and the full size drives in external housings often failed. YMMV.