1
\$\begingroup\$

I'm reading documentation about this component: https://www.microchip.com/en-us/product/LAN7800 .

It is a Ethernet to USB 3.0 Bridge. In a documentation point appears this:

The USB functionality consists of five major parts. The USB PHY, UDC (USB Device Controller), URX (USB Bulk Out Receiver), UTX (USB Bulk In Transmitter), and CTL (USB Control Block).

The UDC is configured to support one configuration, one interface, one alternate setting, and four endpoints. Streams are not supported in this device. The URX and UTX implement the Bulk-Out and Bulk-In endpoints respectively. The CTL manages Control and Interrupt endpoints.

I'm reading USB Complete by Jan Axelson, and I have seen this table:

enter image description here

Where appears each of the four type transfer types on USB, and appears Bulk, Interrupt and Isochronous transfers as "streams", only control appears as message. If streams are not supported by the component, only can be used with control transfers or I'm understanding wrong the datasheet?

Thank you so much.

\$\endgroup\$

1 Answer 1

Reset to default
2
\$\begingroup\$

Control transfers are not suitable for data transmissions. They are meant for setting up a logic channel.

URX (USB Bulk Out Receiver), UTX (USB Bulk In Transmitter)

That is the answer: Microchip's bridge supports bulk transfer, that is, high speed asynchronous (*) data transfer.

(*) In this context asynchronous means that the USB host or the USB device can transfer data at any time.

Isochronous, which is the opposite of asynchronous, is meant, for example, for USB audio speakers that need data (digital voice packets) every a certain time interval negotiated when setting up a logic channel.

This component DOES NOT support video transmissions.

Read page 19 of the datasheet:

https://ww1.microchip.com/downloads/en/DeviceDoc/LAN7800-Data-Sheet-DS00001992G.pdf

enter image description here

\$\endgroup\$
3
  • \$\begingroup\$ Thank you for your reply, very clarifying. Then this component don't support video transmission, right? \$\endgroup\$
    – Juanma
    Nov 17, 2021 at 13:50
  • 1
    \$\begingroup\$ I enhanced my previous answer. \$\endgroup\$
    – Enrico Migliore
    Nov 17, 2021 at 14:16
  • \$\begingroup\$ Thank you so much for your answer Enrico! \$\endgroup\$
    – Juanma
    Nov 17, 2021 at 14:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.