SMSC LAN9311 User Manual

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface

Revision 1.4 (08-19-08)

422

SMSC LAN9311/LAN9311i

 

This register is used to read and write the Random Discard Weight table. A write to this address
performs the specified access. This table is used to set the packet drop probability verses the buffer
usage.

For a read access,  t he 

 can be read following a write to this register.

For a wr ite access, the 

 should be written before writing this register.

Register #:

1C09h

Size:

32 bits

31:5

RO

-

4

Random Discard Weight Table RnW
Specifies a read (1) or a write (0) command.

R/W

0b

3:0

Random Discard Weight Table Index
Specifies the buffer usage range that is accessed.

There are a total of 16 probability entries. Each entry corresponds to a range 
of the number of buffers used by the ingress port. The ranges are structured 
to give more resolution towards the lower buffer usage end.

R/W

0h

0 to 7

8 to 15

16 to 23

24 to 31

32 to 39

40 to 47

48 to 55

56 to 63

64 to 79

80 to 95

96 to 111

112 to 127

128 to 159

160 to 191

192 to 223

224 to 255