SMSC LAN9312 - Manual (Page 386)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
Revision 1.4 (08-19-08) 386 SMSC LAN9312
DATASHEET
14.5.3.18 Switch Engine Admit Only VLAN Register (SWE_ADMT_ONLY_VLAN)
This register is used to configure the per port ingress rule for allowing only VLAN tagged packets.
Register #: 1842h Size: 32 bits
BITS DESCRIPTION TYPE DEFAULT
31:3 RESERVED RO -
2:0 Admit Only VLAN
When set, untagged and priority tagged packets are filtered.
The VLAN Enable bit in the Switch Engine Global Ingress Configuration
Register (SWE_GLOBAL_INGRSS_CFG) needs to be set for these bits to
have an affect.
There is one enable bit per ingress port. Bits 2,1,0 correspond to switch
ports 2,1,0 respectively.
R/W 000b