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Initialization Sequence: The USB module is initialized in the sequence shown in figure 18.14.
1. The LSI is placed in a power off state or hardware standby mode.
2. Turn the power on, apply a high level to the STBY pin, and finally apply a high level to the
RES pin to initiate the LSI operation.
3. Check the VBUS line (USB cable) by firmware.
4. Cancel module stop mode of the USB module by firmware.
5. Set the VBUSS bit in USBCR1 to 1 by firmware.
6. Specify UPLLCR by firmware and wait for USB operating clock PLL stabilization time (3
ms).
7. Set the CK48READY bit in USBCR1 to 1 by firmware.
8. Clear the UIFRST bit in USBCR0 to 0 by firmware and specify the USB module related
registers.
9. Clear the FPLLRST bit in USBCR0 to 0 by firmware.
10. After the DPLL operation stabilization time has passed, clear the FSRST bit in USBCSR0 to 0
by firmware.
11. Write EPINFO to the USB function core and set the EPIVLD bit in USBCR0 to 1 by firmware.
12. Specify external pull-up resistors to be connected by firmware.
13. Wait for a bus reset interrupt .
•
The host executes the bus reset.
The host configures the USB function core. → The USB function core initiates operation.
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Section 18 Universal Serial Bus Interface (USB)
Rev. 3.00 Jan 25, 2006 page 623 of 872
REJ09B0286-0300
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