FTDI Community

Please login or register.

Login with username, password and session length.
Advanced Search  

News:

Welcome to the FTDI Community!

Please read our Welcome Note

Technical Support enquires
please contact the team
@ FTDI Support


New Bridgetek Community is now open

Please note that we have created the Bridgetek Community to discuss all Bridgetek products e.g. EVE, MCU.

Please follow this link and create a new user account to get started.

Bridgetek Community

Author Topic: Poor throughput via USB Bulk transfer VNC2  (Read 9495 times)

GHinchliffe

  • Newbie
  • *
  • Posts: 3
    • View Profile
Poor throughput via USB Bulk transfer VNC2
« on: September 07, 2018, 11:15:40 AM »

Hi,
  I am building an adaptor device based around the Vinculum-II device.  This adaptor will need to maintain a throughput of around 170KB/s (bytes not bits), which should be easy via USB. 

However I am struggling to get anything above around 1.7 KB/s !!  If I strip out all mutex locks, semaphores and have the FTDI device simply throw away data it receives I manage to up that to about 10KB/s.  This is essentially just calling the IOCTL to read from the endpoint, in a loop with the maximum buffer size of 1024 bytes.  Data is being sent with a single libusb bulk transfer command from a linux host.

All USB tasks have a priority of 31, the task reading from USB is running at priority 20.  I have tried removing the vos_memset and vos_memcpy calls and this gets me an extra ~1KBs (but obviously renders the code useless)

Is there something obvious I could have overlooked? or is the VNC2 not capable of achieving the throughput I require? 

Logged

FTDI Community

  • Administrator
  • Hero Member
  • *****
  • Posts: 892
    • View Profile
Re: Poor throughput via USB Bulk transfer VNC2
« Reply #1 on: September 12, 2018, 09:44:56 AM »

This is being handled via email and any solution will be posted here for other user's benefit.

FTDI Community
Logged