SMSC LAN9312 - Manual (Page 439)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
SMSC LAN9312 439 Revision 1.4 (08-19-08)
DATASHEET
6:3 Drop Reason A
When bit 0 is set, these bits indicate the reason a packet was dropped. See
the Drop Reason B description above for definitions of each value of this
field. RC 0h
2:1 Source port A
When bit 0 is set, these bits indicate the source port on which the packet
was dropped.
00 = Port 0
01 = Port 1
10 = Port 2
11 = RESERVED
RC 00b
0 Set A Valid
When set, bits 6:1 are valid. RC 0b
BITS DESCRIPTION TYPE DEFAULT