Freescale Semiconductor MCF52277 Reference Manual page 383

Field
31–14 Reserved, must be cleared.
13–0 Frame index. The value in this register increments at the end of each time frame (microframe). Bits [N– 3] are
FRINDEX for the frame list current index. This means each location of the frame list is accessed 8 times per frame (once
each microframe) before moving to the next index.
In device mode, the value is the current frame number of the last frame transmitted and not used as an index.
In either mode, bits 2–0 indicate current microframe.
Table 20-23 illustrates values of N based on the value of the USBCMD[FS] field when used in host mode.
USBCMD[FS]
20.3.4.5 Periodic Frame List Base Address Register (PERIODICLISTBASE)
This register contains the beginning address of the periodic frame list in the system memory. The host
controller driver loads this register prior to starting the schedule execution by the controller. The memory
structure referenced by this physical memory pointer assumes to be 4-Kbyte aligned. The contents
combine with the FRINDEX register to enable the controller to step through the periodic frame list in
sequence.
The host and device mode functions share this register. In host mode, it is the PERIODICLISTBASE
register; in device mode, it is the DEVICEADDR register. See
(DEVICEADDR)," for more information.
Address: 0xFC0B_0154 (PERIODICLISTBASE)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
R
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Figure 20-20. Periodic Frame List Base Address Register (PERIODICLISTBASE)
Freescale Semiconductor
Table 20-22. FRINDEX Field Descriptions
Table 20-23. FRINDEX N Values
Frame List Size
000 1024 elements (4096 bytes)
001 512 elements (2048 bytes)
010 256 elements (1024 bytes)
011 128 elements (512 bytes)
100 64 elements (256 bytes)
101 32 elements (128 bytes)
110 16 elements (64 bytes)
111 8 elements (32 bytes)
PERBASE
MCF52277 Reference Manual, Rev. 1
Universal Serial Bus Interface – On-The-Go Module
Description
FRINDEX N value
12
11
10
9
8
7
6
5
Section 20.3.4.6, "Device Address Register
9
0 0 0 0 0 0 0 0 0 0 0 0
Access: User read/write
8 7 6 5 4 3 2 1 0
20-25