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Is there an error report for USB packet retransmits
Posted: Tue Jun 30, 2020 4:36 am
by sabdulqadir
Hi,
I am using stm32f723 and as a usb cdc device. I was trying to see if there is any api available which gives me health status of my usb link. How many packets got dropped or retransmitted etc. Would you guys know of any such stats available?
Thanks,
AQ
Re: Is there an error report for USB packet retransmits
Posted: Tue Jun 30, 2020 5:19 am
by Giovanni
Hi,
There is no such API, not all USB peripherals support that kind of statistics.
Giovanni
Re: Is there an error report for USB packet retransmits
Posted: Wed Aug 19, 2020 1:19 am
by sabdulqadir
Thanks for the reply Giovanni, appreciate it.
Pertaining to the same concern, let me ask another one. USB packets have a crc based on which packets are accepted or rejected. Once a packet is rejected, would you know if retransmission happens? and if it does, is it handled by usb stack firmware?
We see over the course of transferring big files over virtual com port, we do lose some packets.
Thanks,
AQ
Re: Is there an error report for USB packet retransmits
Posted: Wed Aug 19, 2020 11:26 am
by Giovanni
Hi,
Re-transmission is handled by the USB HW, the driver is not even handling it.
Giovanni