a strange delay in USB2.0

Ascs_4819156 · ‎Oct 21, 2021

Dear Sir,

I am using CYUSB3014 to develop a camera. Now it works normally at USB3.0 mode. But if I connect it to the USB2.0 port, it does not work well.

In high speed mode(USB2.0), when I read a value from the device, it always have a unbelieve delay, even if in the firmware I return a fake value when receive the request.

For example, By bushound, I can monitor the time. If I send out the request at 15:01:26:540, then after about 13 millisecond, I will get the fake return value at 15:01:26:553. But in Super speed mode(USB3.0), the fake value will be reported at the same time or only need 1 millisecond.

Does anyone know what happened?

Thanks

Chad

AliAsgar · ‎Nov 10, 2021

Hi Chad,

Answering to one of your posts above, the short duration in the control IN requests could be removed by following the firmware workaround mentioned in the first post of mine, where suspending of other channels is avoided during a control IN transfer.

After this workaround is implemented, could you try controlling (lowering) the BULK IN data time and see if the issue persists? and if the issue is not seen, is the data corrupted?

We need to find out where the firmware is getting stuck. For this you could do the following:

1. If the UART traces are coming out of the board, you could connect the UART lines to a USB converter and get the UART logs, if not,
2. You could try the CDC approach and get the logs, if not,
3. You could add CyU3PDeviceReset(CyTrue) to find out the places in the firmware which is getting executed and which is not.

Best Regards,
AliAsgar

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a strange delay in USB2.0

a strange delay in USB2.0

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