Usb Function Control; Relationship Between Packets And Operation Modes - NEC switch User Manual

8.7 USB Function Control

8.7.1 Relationship between packets and operation modes

The relationship between packets and operation modes in the USB function is as follows.
(1) Control transfer (OUT) (Transfer byte count: 8 bytes or less)
Packet flow
Packet from
host controller
SETUP
Setup
stage
DATA0
OUT
Data
stage OUT
reception
DATA1
Status
IN
stage IN
reception
ACK
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CHAPTER 8 USB FUNCTION
Packet from
Operation of host
µ
PD789800
controller
ACK
ACK
DATA1
User's Manual U12978EJ3V0UD
Request
OUT packet
IN packet
ACK packet
Operation of USB
µ
function of PD789800
ACK transmission
reservation
• ACK transmission
• NAK transmission
reservation
• NAK transmission
reservation clear
• ACK transmission
reservation
• ACK transmission
• DATA1 transmission
reservation
DATA1 transmission
NAK transmission
reservation