USB device question


I am debugging s3c2410's usb device driver for linux, I have connect the VCC, GND, D+, D- and the usb device end can detect the insert/plug of usb cable. I installed a IRQ handler for the usb device and it can recieve some interrupt of reset when I insert the USB to host.

But after the reset, no further interrupt happen. Even in the host side there are nothing displayed. I want to know how can I debug it?

According the USB spec, after the HOST hub send Reset to device, the device need to pull up/down a data line to indicate the existence of the device, can I measure this signal on the four lines? Which line should I measure?

I think the host didn't begin to enumerate the device because the device didn't send ACK of the reset to indicate the attach.

Thanks. Bin

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Bin Chen
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Which version of USB are you using ? USB 1.1/USB 2.0.

Karthik Balaguru

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There are flow charts in appendix C of the USB spec that show the reset handling, and the text is in section

Tim Roberts,
Providenza & Boekelheide, Inc.
Reply to
Tim Roberts

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