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USB 1.1 vs. 2.0 and USBTMC

Hi group-

I'm hoping some USB knowledgeable persons can help with this USBTMC (Test & Measurement Class) question...

USBTMC prescribes two descriptors that are supported under 2.0 but not

1.1. They are the device qualifier and other-speed configuration descriptors. Neither have anything to do with USBTMC. Instead they seem to exist for 2.0 high-speed support.

Does anyone know if it's a violation of the the USBTMC standard to implement USBTMC under the 1.1 standard thus forgoing the two extra 2.0 descriptors?

JJS

Reply to
johnspeth
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This is a very wide-spread misunderstanding, but complying to USB 2.0 does not imply high-speed. I have made many USB 2.0 compliant full-speed devices, implemented using existing chips originally designed for USB 1.1.

Set bcdUSB to 0x200, and stall when the host ask for the device qualifier. Thats all. Remember to test your implementation with usbcv.

Leo Havmøller.

Reply to
Leo Havmøller

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