Datasheet

Table Of Contents
Section 15 Universal Serial Bus Interface (USB)
Page 548 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
15.5.2 USB Cable Connection/Disconnection
(1) USB Cable Connection (When USB Module Stop or Software Standby Is Not Used)
If the USB cable enters the connection state from the disconnection state in an application (self
powered) where USB module stop or software standby mode is not used, perform the operation
shown in figure 15.4. In bus-powered mode, perform the operation described in note 2.
Connect the USB cable
USB function
Firmware
Receive bus reset from the host
A bus reset interrupt occurs.
A VBUS interrupt occurs
Check if VBUSs in UIFR3
is set to 1
Enable D+ pull-up by the
port
Check the USB cable
connection state
Initialize the firmware
Ye s
No
Wait for a setup interrupt
Cancel UDC core reset
Clear UDCRST in UCTLR to 0
Clear all FIFOs
Complete the USB module
initialization
Clear VBUSi in UIFR3
System ready?
Automatical load
EPINFO to UDC core
*
1
EXIRQx
EXIRQx
Notes: 1. A VBUS interrupt in the USB module cannot be detected in the software standby state or in the USB module stop state.
2. During the password function, power is applied after the USB cable has been connected.
Accordingly, immediately after completing the power-on reset, initialization (15.5.1), clearing all FIFO,
and system preparation, enable the D+ pull-up via a general port and cancel the UDC core reset state.
from 15.5.1
After completing the bus-
powered function initialization
*
2
Figure 15.4 USB Cable Connection
(When USB Module Stop or Software Standby Is Not Used)