HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 545

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

• Detection of USB Cable Connection/Disconnection
18.4.2
Figure 18.4 shows example connections of the USB host controller and external circuit. When
using the USB host controller, a separate LSI must be used for USB power bus control (equivalent
to the USB power control LSI’s in figure 18.4). Make sure the LSI has the power supply capacity
to satisfy the USB standard, and select one that has an overcurrent protection function. Configure
the system so that the input to the USB_OVR_CRNT pin is Low on detection of an overcurrent.
As USB function controller in this LSI manages the state by hardware, USB_VBUS signal is
necessary to recognize connection or disconnection of the USB cable. The power supply signal
(VBUS) in the USB cable is used for USB_VBUS. However, if the cable is connected to the
USB host or hub when the power of USB function controller (this LSI—installed system) is
off, a voltage of 5 V will be applied from the USB host controller or hub.
Therefore, use an IC such that allows voltage application when system power is off (for
example, HD74LV1G08A) for the IC1 in figures 18.2 to 18.3.
Figure 18.4 Example of Connection USB Host Controller and External Circuit
Example of the Connection between USB Host Controller and External Circuit
USB host controller
USB_OVR_CRNT
This LSI
USB_PWR_EN
USB_N
USB_P
27Ω
27Ω
power control
15kΩ
15kΩ
USB
LSI
Rev. 1.00, 02/04, page 507 of 804
USB connector
5V
GND
D+
D−