SMSC LAN9312 - Manual (Page 409)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
SMSC LAN9312 409 Revision 1.4 (08-19-08)
DATASHEET
14.5.3.40 Switch Engine Interrupt Pending Register (SWE_IPR)
This register contains the Switch Engine interrupt status. The status is double buffered. All interrupts
in this register may be masked via the
Switch Engine Interrupt Mask Register (SWE_IMR) register.
Refer to Chapter 5, "System Interrupts," on page 49 for more information.
Register #: 1881h Size: 32 bits
BITS DESCRIPTION TYPE DEFAULT
31:15 RESERVED RO -
14:11 Drop Reason B
When bit 8 is set, these bits indicate the reason a packet was dropped per
the table below: RC 0h
BIT
VALUES DESCRIPTION
0000 Admit Only VLAN was set and the packet was untagged or priority tagged.
0001 The destination address was not in the ALR table (unknown or broadcast),
Enable Membership Checking on ingress was set, Admit Non Member was
cleared and the source port was not a member of the incoming VLAN.
0010 The destination address was found in the ALR table but the source port was
not in the forwarding state.
0011 The destination address was found in the ALR table but the destination port
was not in the forwarding state.
0100 The destination address was found in the ALR table but Enable Membership
Checking on ingress was set and the destination port was not a member of the
incoming VLAN.
0101 The destination address was found in the ALR table but the Enable
Membership Checking on ingress was set, Admit Non Member was cleared and
the source port was not a member of the incoming VLAN.
0110 Drop Unknown was set and the destination address was a unicast but not in
the ALR table.
0111 Filter Multicast was set and the destination address was a multicast and not in
the ALR table.
1000 The packet was a broadcast but exceeded the Broadcast Throttling limit.
1001 The destination address was not in the ALR table (unknown or broadcast) and
the source port was not in the forwarding state.
1010 The destination address was found in the ALR table but the source and
destination ports were the same.
1011 The destination address was found in the ALR table and the Filter bit was set
for that address.
1100 RESERVED
1101 RESERVED
1110 A packet was received with a VLAN ID of FFFh
1111 RESERVED