Specifications

V850E2/MN4 USB CDC (Communication Device Class) Driver
R01AN0010EJ0101 Rev.1.01 Page 24 of 117
Feb 01, 2012
4.2.2 USB Function Controller Initialization Processing
The USB function controller initialization processing routine sets up the parameters necessary for starting the use of the
USB function controller.
Start of USB
initialization
Configure D+ signal for
no connection
Set up supply of UCLK
Initialize EPC circuit
Initialize USBF buffer
Set up interfaces and
endpoints
Reset NAK setting for
control endpoint
Initialize internal driver flags
Configure D+ signal for pull-up
End of USB
initialization
Set up NAK for control
endpoint
Initialize request data
register area
Figure 4.3 USB Function Controller Initialization Processing Flow
(1)
Configuring the D+ signal as Pull Down
Loads the CPU’s P4.10 with “0.” This sets the D+ signal low, disabling the host side to detect any device connection.
(2)
Setting up for the Supply of UCLK
Loads the SFRCTL3 register with “0x48” to enable the clock to be supplied to the USB function.