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USB 2.0 Hi-Speed Hub Controller
Datasheet
Revision 1.0 (3-11-09) 48 SMSC USB251x
DATASHEET
8.2.1.31 Register FBh: PortMap 12
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PRTR12 PortMap register for ports 1 & 2.
When a hub is enumerated by a USB host controller, the hub is only
permitted to report how many ports it has; the hub is not permitted to select
a numerical range or assignment. The host controller will number the
downstream ports of the hub starting with the number '1', up to the number
of ports that the hub reported having.
The host's port number is referred to as "Logical Port Number" and the
physical port on the hub is the “Physical Port Number". When mapping mode
is enabled (see PRTMAP_EN in Register 08h: Configuration Data Byte 3)
the hub's downstream port numbers can be mapped to different logical port
numbers (assigned by the host).
Note: OEM must ensure that contiguous logical port numbers are used,
starting from #1 up to the maximum number of enabled ports; this
ensures that the hub's ports are numbered in accordance with the
way a host will communicate with the ports.
Table 8.3 PortMap Register for Ports 1 & 2
Bit [7:4] ‘0000’ Physical Port 2 is Disabled
‘0001’ Physical Port 2 is mapped to Logical Port 1
‘0010’ Physical Port 2 is mapped to Logical Port 2
‘0011’ Physical Port 2 is mapped to Logical Port 3
‘0100’ Physical Port 2 is mapped to Logical Port 4
‘0101’ Physical Port 2 is mapped to Logical Port 5
‘0100’ Physical Port 2 is mapped to Logical Port 6
‘0111’ Physical Port 2 is mapped to Logical Port 7
‘1000’
to
‘1111’
Reserved, will default to ‘0000’ value
Bit [3:0] ‘0000’ Physical Port 1 is Disabled
‘0001’ Physical Port 1 is mapped to Logical Port 1
‘0010’ Physical Port 1 is mapped to Logical Port 2
‘0011’ Physical Port 1 is mapped to Logical Port 3
‘0100’ Physical Port 1 is mapped to Logical Port 4
‘0101’ Physical Port 1 is mapped to Logical Port 5
‘0110’ Physical Port 1 is mapped to Logical Port 6
‘0111’ Physical Port 1 is mapped to Logical Port 7
‘1000’
to
‘1111’
Reserved, will default to ‘0000’ value