6.20 usb stack issue

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David Raimond

6.20 usb stack issue

Post by David Raimond » Wed Oct 02, 2002 8:27 am

Hi everyone,

I meet an issue with the 6.20 USB stack on a x86 platform.
When a new USB device is plugged, a pull-up resistor (on D+ or D-) allows to
determine the speed characteristic of this new peripheral (D+ for a high
speed one and D- for a slow speed device). The USB 1.1 specification
(september 23th 1998) indicates in the paragraph that the timing
(Tattdb = debounce interval provided by USB system software after attach)
between the device connection detection (D+ or D- uprise signal) and the hub
reset port must be a minimum of 100 ms (see figure 7-19 p.120 of the
specification). With QNX usb stack, we scoped a timing between 8.8 ms and
260 ms, depending of the CPU load. If the reset port appears before 100 ms,
our specific devices don't start.

Does anyone could tell me if this issue will be corrected in the next OS
patch / release ?
Thank for your answer.

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