I have developed an am3359 card . I use the USB1 as host. In schematic, usb_Bus5v is connected directly to the pcb 5v.
When plug the U disk to the 3359, it work well, and can read or write.
The question is, when unplug the u disk, occasionally, rarely （ 1/10） will give :usb1 babble interrupt occured! please issue long reset to make the usb work functional !
I didn't use a power switch like the evm schematic, use AM3559_USB1_DRVVBUS to control the switch to power off or on the u dsik, may this be the question? I tried umount the u disk and then unplug the disk, the error still will appear. beacause I dont use the DRWBUS pin, so maybe there is no differences between unmount and unplug the disk directly.
The capacity on the USBbus is 0.1 uF, maybe it‘s too small , I will solder a 10 uF on it later.
I really want to know how the babble error appear.
Reason maybe The USB layout is not good, gets Signal integrity problem？But it can work well before unplug the usb disk.
Or when unplug the usb disk, makes lots of noise on the usb power pin,then make the babble? I have seen a test
report said that when add noise to the usb 5v, then will make the usb report babble ? I later will test a usb hub. First plug a hub in 3359, and next plug or unplug u disk to the hub, to find the error appear or not.
Thank you for your reply!