Figure 20.11 Ep2 Bulk-In Transfer Operation - Renesas HD6417641 Hardware Manual

USB function
IN token reception
Valid data
in EP2 FIFO?
Yes
Data transmission to host
ACK
Space
in EP2 FIFO?
No
Clear EP2 empty status
(USBIFR0/EP2 EMPTY = 0)

Figure 20.11 EP2 Bulk-IN Transfer Operation

Interrupt request
No
NACK
Set EP2
Yes
empty status
(USBIFR0/EP2
EMPTY = 1)
Section 20 USB Function Module
Application
Clear EP2 transfer
request flag
(USBIFR0/EP2 TR = 0)
Enable EP2 FIFO
empty interrupt
(USBIER0/EP2 EMPTY = 1)
Interrupt
request
USBIER0/EP2 EMPTY
interrupt
Write one packet of data
to USBEP2 data register
(USBEPDR2)
Write 1 to EP2 packet
enable bit
(USBTRG/EP2 PKTE = 1)
Rev. 4.00 Sep. 14, 2005 Page 777 of 982
REJ09B0023-0400