Universal Serial Bus OHCI Host Controller User's Guide

3.7 HC HCAA Address Register (HCHCCA)
3.8 HC Current Periodic Register (HCPERIODCURRENTED)
www.ti.com Registers
The HC HCAA address register (HCHCCA) defines the physical address of the beginning of the HCCA.
HCHCCA is shown in Figure 8 and described in Table 8 .
Figure 8. HC HCAA Address Register (HCHCCA)
31 16
HCCA
R/W-0
15 8 7 0
HCCA Reserved
R/W-0 R-0
LEGEND: R/W = Read/Write; R = Read only; - n = value after reset
Table 8. HC HCAA Address Register (HCHCCA) Field Descriptions
Bit Field Value Description
31-8 HCCA 0-FF FFFFh Physical address of the beginning of the HCCA.
7-0 Reserved 0 Reserved
The HC current periodic register (HCPERIODCURRENTED) defines the physical address of the next
endpoint descriptor (ED) on the periodic ED list. HCPERIODCURRENTED is shown in Figure 9 and
described in Table 9 .
Figure 9. HC Current Periodic Register (HCPERIODCURRENTED)
31 16
PCED
R-0
15 4 3 0
PCED Reserved
R-0 R-0
LEGEND: R = Read only; - n = value after reset
Table 9. HC Current Periodic Register (HCPERIODCURRENTED) Field Descriptions
Bit Field Value Description
31-4 PCED 0-FFF FFFFh Physical address of the current ED on the periodic ED list. This field represents bits 31-4 of the
physical address of the next ED on the periodic ED list. EDs are assumed to begin on a 16-byte
aligned address, so bits 3-0 of this pointer are assumed to be 0. For the restrictions on physical
addresses, see Section 2.7 .
3-0 Reserved 0 Reserved
SPRUFM8 – September 2008 Universal Serial Bus OHCI Host Controller 19
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