HD6417705F133V Datasheet, PDF (502/741 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

18.4 Operation
18.4.1 Cable Connection
USB function
Cable disconnected
VBUS pin = 0 V
UDC core reset
USB cable connection
Application
USB module interrupt
setting
As soon as preparations are
completed, enable D+ pull-up
in general output port
Initial
settings
No
General output port
D+ pull-up enabled?
Yes
IFR1.VBUS = 1
Interrupt request
USB bus connection interrupt
Clear VBUS flag
(IFR1.VBUS)
UDC core reset release
Firmware preparations for
start of USB communication
Bus reset reception
IFR0.BRST = 1
Bus reset interrupt
Interrupt request
Clear bus reset flag
(IFR0.BRST)
Wait for setup command
reception complete interrupt
Clear FIFOs
(EP0, EP1, EP2, EP3)
Wait for setup command
reception complete interrupt
Figure 18.2 Cable Connection Operation
The above flowchart shows the operation in the case of in section 18.8, 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. 2.00, 09/03, page 454 of 690