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From: Srini <sinax_usb@y...>
Date: Thu, 13 Feb 2003 21:35:51 -0800 (PST)
Subject: [usb] Info Reqd

Hi All,

I am writing a USB2.0 Device Stack.At present i dont hav any hardware so i am simulaing a few h/w functionalities in s/w itself.

For h/w functional referene i used the "ARC USB CONTROLLER CORE" document.

My understanding after reading the document as to what a device does when it has some data to send is :

When the device has a Data to send, it will update the Control Register with the address of the buffer that has the data.The h/w when it receives an IN token, looks at the control register of the corresponding endpoint.If the buffer address is valid it will transmit the data pointed by the buffer.

My question is:

Every endpoint has a Maxpkt size.If the data to be sent to the host is more than Maxpktsize for that endpoint, who will take care of sending the pkts whose size equal to maxpkt size.Is it h/w or s/w responsibility??

The s/w can just point to the buffer that has the data, without bothering abt the size of the data, will h/w send the data as multiple maxsize pkts??

Thanks and Regards,

Srinivas

Reference	Author
[usb] how to detect if a valid handshake is received	M Dennis