Flowchart Of Usb Timer Operation - NEC switch User Manual

1
Idle state
SYNC detected?
Y
USB timer reset
USB timer start
(low-speed mode)
EOP received?
Y
USB timer reset
SETUP/OUT
packet?
Y
SETORX
N
(internal signal)
= 1?
Y
3
UWDERR: Bit 7 of packet receive status register (RXSTAT)
CHAPTER 8
Figure 8-20. Flowchart of USB Timer Operation (1/2)
N
2
N
N
IN packet?
Y
Transmit data
transferring?
Y
Transmit EOP is
output?
Y
DATA TX
(internal signal)
= 1?
Y
User's Manual U12978EJ3V0UD
USB FUNCTION
Low-speed
mode overflow?
INTUSBTM occurred
UWDERR set
(inadvertent program
loop detection)
N
N
N
N
N
Y
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