Renesas H8S/2158 User Manual page 674

Section 18 Universal Serial Bus Interface (USB)
USB Bus Reset State: When a new device is connected to the USB bus or when en error recovery
process is executed, the USDP/USDM pin is placed in a bus reset state for a specific period.
In the USB module, the bus reset interrupt flag is set to 1 when a USB bus reset is detected. The
USB module internal status and control registers that select the USB module operating state are
not initialized by a USB bus reset. Registers must be initialized individually as required. When the
USB function core is initialized by the FSRST bit in USBCR0, endpoint information (EPINFO)
and bus reset detection information of the USB function core are also initialized. Therefore,
initialization by the FSRST or UIFRST bit in USBCR0 should not be performed in the bus reset
interrupt processing.
USB Suspend State: The USB function core enters a suspend state when the USB bus is placed in
an idle state for a specific period. In a suspend state, power consumption can be reduced by
stopping the PLL circuit after clearing the CK48READY bit in USBCR1 to 0. A suspend state
combined with a low-power consumption mode can effectively reduce the power consumption
while the system is not in operation.
When the USB function core enters a suspend state or when the suspend state is cancelled by the
signal change on the USDP/USDM pin, the suspend IN and OUT interrupt flags are set to 1,
respectively. An SPNDOF interrupt can be accepted by waking up this LSI even if this LSI is
placed in software standby mode.
Rev. 3.00 Jan 25, 2006 page 620 of 872
REJ09B0286-0300