Information

Universal Serial Bus Interface

MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1

13-24 Freescale Semiconductor

There are two operations that can be performed with the ULPI viewport, wakeup and read /write

operations. The wakeup operation is used to put the ULPI interface into normal operation mode and

re-enable the clock if necessary. A wakeup operation is required before accessing the registers when the

ULPI interface is operating in low power mode, serial mode, or carkit mode. The ULPI state can be

determined by reading the sync state bit (ULPISS). If this bit is set, then the ULPI interface is running in

normal operation mode and can accept read/write operations. If the ULPISS is cleared, then read/write

operations will not be able execute. Undefined behavior results if a read or write operation is performed

when ULPISS is cleared. To execute a wakeup operation, write all 32-bits of the ULPI Viewport where

ULPIPORT is constructed appropriately and the ULPIWU bit is set and the ULPIRUN bit is cleared. Poll

the ULPI Viewport until ULPIWU is cleared for the operation to complete.

To execute a read or write operation, write all 32-bits of the ULPI Viewport where ULPIDATWR,

ULPIADDR, ULPIPORT, ULPIRW are constructed appropriately and the ULPIRUN bit is set. Poll the

ULPI Viewport until ULPIRUN is cleared for the operation to complete. For read operations,

ULPIDATRD is valid once ULPIRUN is cleared.

The polling method above can be replaced with interrupts using the ULPI interrupt defined in the USBSTS

and USBINTR registers. When a wakeup or read/write operation completes, the ULPI interrupt is set.

13.3.2.13 Configure Flag Register (CONFIGFLAG)

This EHCI register is not used in this implementation. A read from this register returns a constant of a

0x0000_0001 to indicate that all port routings default to this host controller.

Figure 13-19 shows the configure flag register.

23–16 ULPIADDR When a read or write operation is commanded, the address of the operation is written to this

field.

15–8 ULPIDATRD After a read operation completes, the result is placed in this field.

7–0 ULPIDTWR When a write operation is commanded, the data to be sent is written to this field.

Offset 0x180 Access: Read only

31 10

—

Reset00000000000000000000000000000001

Figure 13-19. Configure Flag Register (CONFIGFLAG)

Table 13-21. ULPI VIEWPORT Field Descriptions (continued)

Bits Name Description