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Linux/AM3352: USB Host mode issue

yimin bai34
Genius 4755 points
Part Number: AM3352


Tool/software: Linux

Hi Sir 

we used AM3352 with latest SDK for development. 

1. we set AM3352 USB port as host mode and connect it to our printer end device (peripheral mode)

2. we found the AM3352 always sends 512 bytes data each time and the speed is lower than we used other platform to do comparison.

3. below photo shows it sends 512 bytes each time

if we used other platform , the bytes transferred can be up to 93184 bytes.

4.after analyzing the packet Transmission in more detail, we found AM3352 has three and above SOF package after sending one 512bytes.

please advise how to increase the USB Transmission speed or how to send continuous 512bytes ?

BTW, let us know what information we should offer to you

thanks for your suggestion

BR

Yimin

  • 0
    TI__Guru**** 393215 points
    Please post more details on USB configuration. What is the speed you see?
  • 0 in reply to Biser Gatchev-XID
    TI__Guru**** 393215 points
    Is this resolved? If so, please mark the thread as answered so we can close it.
  • 0
    TI__Guru**** 172861 points

    Yimin,

    Sorry for the late response, I just got back from the holiday break.

    I don't see such 512-bytes transfer problem when writing data to USB thumb drives. Then I did the following test.

    Taking one EVM loading with g_printer driver, connecting its usb peripheral port to AM335x EVM USB host port, then transmitting data from AM335x to the printer gadget EVM.

    On g_printer gadget evm:

    # cat /dev/g_printer0 > /dev/null

    On AM335x EVM:

    # cat test.log > /dev/usb/lp0

    And here is the captured bus trace, which shows 4KB transfers.

    What printer driver do you use on AM335x? Is it already included in the Linux kernel or you have to install it separately?