HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 542

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

Bit
1
0
Rev. 1.00, 02/04, page 504 of 804
Bit Name
USBFSTP
USBCLKSEL 0
Initial
Value
0
R/W
R/W
R/W
Descriptions
Module Stop USBF
The USB function controller stop bit to be used to provide
or stop the USB function controller operating clock.
Clearing this bit to 0 provides the clock to the USB
function controller. Setting this bit to 1 stops the clock. If
both the USBHSTP and USBFSTP bits are set to 1 or
cleared to 0, the USB transceiver operation stops. The
USB_P and the USB_N outputs pins enter the high-
impedance state, and then the
USB_PWR_EN/USB_PULLUP pin is brought low. Before
using the USB host or USB function controller, clear one
of USBHSTP and USBFSTP to 0. Note that the USB host
controller and USB function controller cannot be used
simultaneously. If the USB module control register is
accessed while both the USBHSTP and USBFSTP bits
are cleared to 0, correct operation cannot be guaranteed.
Note that the USB function controller register access is
ignored while the clock provided to the USB function
controller is stopped.
0: USB function controller operation continues.
1: Stop providing clock to the USB function controller.
USB Clock Select
The USB clock source select bit used to select whether
the USB clock is internally generated or the USB clock is
externally input. After this bit is modified, both the USB
host and the USB function controllers must be initialized
by the USBRESET bit.
0: The USB clock is generated internally.
1: The USB clock is input by the UCLK pin.