Freescale Semiconductor MCF5480 - Manual (Page 896)

MCF548x Reference Manual, Rev. 3
29-22 Freescale Semiconductor
29.2.2.15 USB Application Interface Update Register (IFUR)
The IFUR is used by the USB application to perform a high-speed update of the alternate setting of a
specified interface. It cannot be addressed as 8 bits. When application software writes to this register, a
parallel compare is done between IFUR[IFNUM] and all the IFRn[IFNUM] fields. If the compare
matches, the matching IFRn’s alternate setting field is automatically updated to the value written in the
IFUR[ALTSET] field. Each field may range from 0x00 through 0xFF.
29.2.2.16 USB Configuration Interface Register (IFRn)
These registers contain the available interface numbers and their current alternate setting. There are 32 of
these registers (one for each of the 32 interfaces and alternate settings supported). Each field may range
from 0x00 through 0xFF.
The application software must program these registers with the valid interface numbers for the current
configuration.
Table 29-15. EPTNR Field Descriptions
Bits Name Description
15–12 — Reserved, should be cleared.
11–0 EPnT Endpoint transactions. Indicates the number of transactions required by high-speed
isochronous endpoints.
00 1 transaction
01 2 transactions
10 3 transactions
11 Reserved
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R
W IFNUM ALTSET
Reset Undefined
Reg
Addr
MBAR + 0xB014
Figure 29-16. USB Application Interface Update Register (IFUR)
Table 29-16. IFUR Field Descriptions
Bits Name Description
15–8 IFNUM Interface number. Compared to the IFRn[IFNUM] field.
7–0 ALTSET Alternate setting. If the IFUR[IFNUM] matches a IFRn[IFNUM] field, then this value is
written into the matching IFRn register’s ALTSET field.