USB data toggle

For bulk and interrupt transfers, the data toggle resets <0> only on set configuration, set interface, and clear feature (endpoint halt ).

For isochronous transfers, the data toggle always is <0> and no ACK

For control transfers,

Out endpoint: hardware clears toggle bit at the specified tion of a setup PID addressed to this endpoint. <to reset ED setup data packet data0>

In endpoint: hardware sets toggle bit at the specified tion of a setup PID addressed to this endpoint. <to send data or status packet data1>

 

Setup: data0: ACK <-- hardware clears toggle bit

In: data1: ACK <-- hardware sets toggle bit

Out: data1: ACK <-- hardware clears toggle bit from data0 to data1

 

Setup: data0: ACK <-- hardware clears toggle bit

Out: data1: ACK <-- hardware toggle bit

In: data1: ACK <-- hardware sets toggle bit

 

Setup: data0: ACK <-- hardware clears toggle bit

In: data1: ACK <-- hardware sets toggle bit