Chapter 14
Control transfers always use DATA0 in the Setup stage, use DATA1 in the first
transaction of the Data stage, toggle the value in any additional Data-stage
transactions, and use DATA1 in the Status stage. Bulk and interrupt endpoints
toggle the value in every transaction, resetting the data toggle only after a bus
reset or on completing a Set Configuration, Set Interface, or Clear Fea-
ture(ENDPOINT HALT) request.