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USB Hub with Integrated 10/100 Ethernet Controller
Datasheet
Revision 1.0 (04-20-09) 26 SMSC LAN9512
DATASHEET
36h Port Remap 12 Register (PRTR12)
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 remapping mode is enabled, (see
Port Re-Mapping Enable (PRTMAP_EN) bit in Config Data Byte 3 Register (CFG3)
Format) the hub’s downstream port numbers can be remapped to different logical port
numbers (assigned by the host).
Note: The 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.
21h
Table 3.3 Hub Configuration (continued)
EEPROM
OFFSET DESCRIPTION DEFAULT
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
All others RESERVED
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
All others RESERVED