Specifications

V850E2/MN4 USB CDC (Communication Device Class) Driver
R01AN0010EJ0101 Rev.1.01 Page 23 of 117
Feb 01, 2012
4.2.1 CPU Initialization Processing
The CPU initialization processing routine sets up the parameters that are necessary for using the USB function
controller.
Start of CPU
initialization
Enable HCLK output
H BUS initialization processing
Initialize USB clock
Initialize VBUS signal
End of CPU
initialization
Figure 4.2 CPU Initialization Processing Flow
(1)
Enabling HCLK Output
This process makes settings to enable the HCLK output so that the USBF connected to the H bus becomes enabled.
Since the SFRCTL2 register used for this setup is a specific write register, a specific write sequence is followed for the
setup.
(2)
H Bus Initialization
This process initializes the H-bus. The routine initializes the H bus according to the specified directions. See the
V850E2/MN4 Microcontroller User’s Manual [Hardware (R01UH0011EJ)].
(3)
Initializing USB Clock
This process sets up the multiplexed pin P13 to which UCLK is connected. This sample driver uses UCLK as the USB
clock input to the USB.
(4)
Initializing VBUS Signal
This process initializes the VBUS signal.