What does the term data toggle mean?

[KenJohnny]

My knowledge is very poor. I've look a term "data toggle". And I can't make clear its meaning. I hope someone can explain this term to me. Thanks!

 

[echo47]

data toggle

Those two words by themselves are not very clear. It could mean that the data changes back and forth between two values each time some event occurs. But that's a weak guess. Can you show us the complete sentence or paragraph?

 

[KenJohnny]

data toggle

This term appears in the datasheet of cy7c68001, a USB device provided by Cypress. The paragraph including the term as below:
"The SX2 automatically responds to all USB standard requests covered in chapter 9 of the USB 2.0 specification except the Set/Clear Feature Endpoint requests. When the host issues a Set Feature or a Clear feature request, the SX2 will trigger a SETUP interrupt to the external master. The USB spec requires that the device respond to the Set endpoint feature request by doing the following:
• Set the STALL condition on that endpoint.
The USB spec requires that the device respond to the Clear endpoint feature request by doing the following:
• Reset the Data Toggle for that endpoint
• Clear the STALL condition of that endpoint.
The register that is used to reset the data toggle TOGCTL (located at XDATA location 0xE683) is not an index register that can be addressed by the command protocol presented in Section 3.7.8. The following section provides further information on this register bits and how to reset the data toggle accordingly using a different set of command protocol sequence."
My bewilderness is, if "data toggle"'s meaning is as you said, how to reset it?
thanks!

 

[echo47]

data toggle

That "Data Toggle" is a specific behavior of USB. I don't know much about USB, but you can read all about it in the official specification:
**broken link removed**