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Universal Serial Bus (USB)
MCF5272 ColdFire Integrated Microprocessor User’s Manual, Rev. 3
12-12
Freescale Semiconductor
12.3.2.6
USB Alternate Settings Register (ASR)
Defines which of several possible interfaces is currently active.
Figure 12-8 shows the USB alternate settings register. The configuration descriptors must be read by the
user in order to determine which interfaces are currently valid.
Figure 12-8. USB Alternate Settings Register (ASR)
Table 12-8 lists field descriptions for the USB alternate settings register.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Field IF15_AS
IF14_AS
IF13_AS
IF12_AS
IF11_AS
IF10_AS
IF9_AS
IF8_AS
Reset
0000_0000_0000_0000
R/W
Read
15
14
13
12
11
10
987
654
321
0
Field
IF7_AS
IF6_AS
IF5_AS
IF4_AS
IF3_AS
IF2_AS
IF1_AS
IF0_AS
Reset
0000_0000_0000_0000
R/W
Read
Addr
MBAR + 0x1014
Table 12-8. ASR Field Descriptions
Bits
Name
Description
31–0
IFn_AS
USB alternate settings for interface n. This field indicates which alternate setting is active for each
interface.
00 Alternate Setting 0
01 Alternate Setting 1
10 Alternate Setting 2
11 Alternate Setting 3