DM8203
2-port switch with MII / RMII Interface
2 in the end.
(4).Exception
The DM8203 has an optional setting that
broadcast/multicast packets are not monitored (see
bit 4 of register 65h). It’s useful to avoid unnecessary
bandwidth.
(1). Set PVID of Port 0 to 0x01h.
(2). Set PVID of Port 1 to 0x02h.
(3). Set PVID of Port 2 to 0x03h.
(4). Set register B1h to 0x06h.
(5). Set register B2h to 0x05h.
(6). Set register B3h to 0x03h.
9.2.13 VLAN Support
9.2.13.1 Port-Based VLAN
The DM8203 supports port-based VLAN as
default, up to 16 groups. Each port has a default VID
called PVID (Port VID, see register 6Fh). The
DM8203 used LSB 4-bytes of PVID as index and
mapped to register B0h~BFh, to define the VLAN
groups.
For instance, we intend to partition DM8203’s
ports into three groups. Port 0 and port 1 in group A,
port 1 and port 2 in group B, finally, port 2 and port 0
in group C. In this case, the setting as below:
9.2.13.2 802.1Q-Based VLAN
Regarding IEEE 802.1Q standard, Tag-based
VLAN uses an extra tag to identify the VLAN
membership of
a
frame across VLAN-aware
switch/router. A tagged frame is four bytes longer
than an untagged frame and contains two bytes of
TPID (Tag Protocol Identifier) and two bytes of TCI
(Tag Control Information).
Dest.
Dest.
Src.
Src.
Length/Type
Data
Standard frame
Tagged frame
TPID
Type
Length /
Data
TCI
0x8100
2 bytes
Priority CFI
VID
VLAN_9013.vsd
3 bits
1 bits
12 bits
User can define each port as Tag port or Un-tag
The DM8203 also supports 16 802.1Q-based
VLAN groups, as specified in bit 1 of register 53h. It’s
obvious that the tagged packets can be assigned to
several different VLANs which are determined
according to the VID inside the VLAN Tag. Therefore,
the operation is similar to port-based VLAN. The
DM8203 used LSB 4-bytes VID of received packet
with VLAN tag and VLAN Group Mapping Register
(B0h~BFh) to configure the VLAN partition. If the
destination port of received packet is not same VLAN
group with received port, it will be discarded.
port by bit 7 of register 6Dh in 802.1Q-based VLAN
mode. The operation of Tag and Un-tag can explain
as below conditions:
(1). Receive untagged packet and forward to
Un-tag port.
Received packet will forward to destination port
without modification.
(2). Receive tagged packet and forward to Un-tag
port.
The DM8203 will remove the tag from the
packet and recalculate CRC before sending it out.
(3). Receive untagged packet and forward to Tag
port.
9.2.13.3 Tag/Untag
46
Preliminary datasheet
DM8203-15-DS-P05
October 23, 2008
DAVICOM [ DAVICOM SEMICONDUCTOR, INC. ]
