Thineshan Kathirchelvan (TA)'s Blog – August 2010 Archive (1)

Transactions: A USB transaction has three parts: the token packet, the optional data packet, and the status packet, which represent the header, payload, and data

acknowledge, respectively. Since USB is host-driven, the host initiates

transactions by sending the token packet. It also sends packets to indicate the

start of each frame, every millisecond. Packets on this layer are taken care

of, so the…