HD6417641 RENESAS [Renesas Technology Corp], HD6417641 Datasheet - Page 816

• Manufacturer Part Number: HD6417641
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 20 USB Function Module
20.4
20.4.1
The flowchart in figure 20.2 shows the operation in the case for section 20.8, Example of USB
External Circuitry.
In applications that do not require USB cable connection to be detected, processing by the USB
bus connection interrupt is not necessary. Preparations should be made with the bus reset interrupt.
Rev. 4.00 Sep. 14, 2005 Page 766 of 982
REJ09B0023-0400
No
Operation
Cable Connection
USB bus connection interrupt
reception complete interrupt
Wait for setup command
UDC core reset release
USB cable connection
D+ pull-up enabled?
USBIFR1/VBUS = 1
USBIFR0/BRST = 1
Cable disconnected
General output port
Bus reset reception
Bus reset interrupt
VBUS pin = 0 V
UDC core reset
USB function
Yes
Figure 20.2 Cable Connection Operation
Interrupt request
Interrupt request
completed, enable D+ pull-up
As soon as preparations are
start of USB communication
reception complete interrupt
Firmware preparations for
Wait for setup command
(EP0, EP1, EP2, EP3)
USB module interrupt
in general output port
Clear bus reset flag
(USBIFR1/VBUS)
(USBIFR0/BRST)
Clear VBUS flag
Clear FIFOs
Application
setting
Initial
settings