hi all,

hehe, what better place to ask things that all other forum don't really answer :)

I'm developing a USB host firmware for an 8051 similar micro, that talk with a SL811HS cypress controller.

I have to get som images (almost one) from a webcam (sn9c102 chipset, PAS106B sensor).
I would receive the images through isochronous transfer mode.
This is the issue: the controller has a maximum buffer of 240 bytes, so i must set the maxPacketSize interface setting of the camera to 128 bytes, otherwise, if i set it greater, i get an overflow error from the controller.

So, if i understand well, in isochronous tranfer i should ask for a single packet for every 1ms frame. Doing so, i get about 2048 bytes of image correctly, but then, the camera restart sending image data from the begin of the image, instade of go-on with the next lines of color data i'm waiting for.
That's really strange, it seems the camera for some reason reset herself and start again from the begin of the image.

So i can't get out. I've posted some treads i the usb forum but they didn't really help me, they answer with questions everytime. If any help, it would be very appreciated :)

Posted on 2004-10-05 02:57:16 by Bit7