MPC5200B Users Guide, Rev. 1
12-16 Freescale Semiconductor
Host Control (HC) Operational Registers
12.4.4 Frame Counter Partition—MBAR + 0x1034
This HC partition uses 5 32-bit registers. These registers are located at an offset from MBAR of 0x1034. Register addresses are relative to
this offset. Therefore, the actual register address is: MBAR + 0x1034 + register address
The following registers are available:
USB HC Frame Interval Register (0x1034)
USB HC Frame Remaining Register (0x1038)
USB HC Frame Number Register (0x103C)
USB HC Periodic Start Register (0x1040)
USB HC LS Threshold Register (0x1044)

12.4.4.1 USB HC Frame Interval Register—MBAR + 0x1034

The HC Frame Interval register contains a 14-bit value that indicates:
the bit-time interval in a Frame. For example, between two consecutive SOFs.
a 15-bit value that indicates the full speed maximum packet size the HC may transmit or receive without causing scheduling
overruns.
HCD may carry out minor adjustment on the frame interval by writing a new value over the present one at each SOF. This provides the
programmability necessary for the HC to synchronize with an external clocking resource and to adjust any unknown local clock offset.

Table12-13. USB HC Done Head Register

msb 012345678 9 101112131415
RDH
W
RESET:000000000 0 0 000 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 lsb
RDH Reserved
W
RESET:000000000 0 0 000 0 0
Bits Name Description
0:27 DH DoneHead—When a TD is complete, HC writes the HcDoneHead content to the TD NextTD
field. HC then overwrites the HcDoneHead content with the TD address. This is set to 0 when
HC writes the register content to HCCA. HcInterruptStatus Wr itebackDoneHead is also set.
28:31 — Reserved

Table12-14. USB HC Frame Interval Register

msb 012345678 9 101112131415
RFIT FSMPS
W
RESET:000000000 0 0 000 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 lsb
RReserved FI
W
RESET:001011101 1 0 111 1 1