NEC switch User Manual page 142

Figure 8-25. Flowchart of Transmit/Receive Pointer Operation (3/7)
(2) Data/Handshake packet reception (1/2)
Idle state
Transmit/receive
signal?
Y
Data/handshake reception
Set USBPOW to 10H
Set USBPOB to 00H
Does
USBPOW match
DRXCON?
N
Bit normal write?
Y
Y
Does bit stuffing
signal = 1?
N
USBPOB increment
N
USBPOB
overflow?
Y
USBPOW increment
USBPOW
= 11H?
N
DBYER: Bit 5 of data/handshake packet receive result store register (DRXRSL)
DRXCON: Data/handshake packet receive byte number counter
142
CHAPTER 8
Y
EOP
Set DBYER flag
Idle state
Y
Set CRC16 execution
start signal
User's Manual U12978EJ3V0UD
USB FUNCTION
Bit normal write?
Y
Y
Does bit stuffing
signal = 1?
N
USBPOB increment
N
USBPOB
overflow?
Y
HSSTAT = 1?
N
Set USBPOW to 70H
2
EOP
Set DBYER flag
Idle state
Y
1