KSZ8893-MQL Micrel Semiconductor, Inc., KSZ8893-MQL Datasheet - Page 57

• Manufacturer Part Number: KSZ8893-MQL
• Description: Integrated 3-Port 10/100 Managed Switch with PHYs
• Manufacturer: Micrel Semiconductor, Inc.

Register 4 (0x04): Global Control 2 (continued)
Bit
4
3
2
1
0
Register 5 (0x05): Global Control 3
Bit
7
6
5
4
Micrel
November 2005
Name
Flow Control
and Back
Pressure Fair
Mode
No Excessive
Collision Drop
Huge Packet
Support
Legal
Maximum
Packet Size
Check Enable
Priority Buffer
Reserve
Name
802.1Q VLAN
Enable
IGMP Snoop
Enable on
Switch MII
Interface
IPv6 MLD
Snooping
Enable
IPv6 MLD
Snooping
Option
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Description
= 1, fair mode is selected. In this mode, if a flow
control port and a non-flow control port talk to the
same destination port, packets from the non-flow
control port may be dropped. This is to prevent the
flow control port from being flow controlled for an
extended period of time.
= 0, in this mode, if a flow control port and a non-flow
control port talk to the same destination port, the flow
control port will be flow controlled. This may not be
“fair” to the flow control port.
= 1, the switch will not drop packets when 16 or more
collisions occur.
= 0, the switch will drop packets when 16 or more
collisions occur.
= 1, will accept packet sizes up to 1916 bytes
(inclusive). This bit setting will override setting from
bit 1 of this register.
= 0, the max packet size will be determined by bit 1 of
this register.
= 0, will accept packet sizes up to 1536 bytes
(inclusive).
= 1, 1522 bytes for tagged packets, 1518 bytes for
untagged packets. Any packets larger than the
specified value will be dropped.
= 1, each port is pre-allocated 48 buffers for high
priority (q3, q2, and q1) packets. This selection is
effective only when the multiple queue feature is
turned on. It is recommended to enable this bit for
multiple queue.
= 0, no reserved buffers for high priority packets.
Each port is pre-allocated 48 buffers for all priority
packets (q3, q2,q1, and q0).
Description
= 1, 802.1Q VLAN mode is turned on. VLAN table
needs to set up before the operation.
= 0, 802.1Q VLAN is disabled.
=1, IGMP snoop is enabled. All IGMP packets will be
forwarded to the Switch MII port.
=0, IGMP snoop is disabled.
IPv6 MLD snooping
1 = enable
0 = disable
IPv6 MLD snooping option
1 = enable
0 = disable
57
Default
1
0
0
SMRXD0
(pin 85)
value
during reset
1
Default
0
0
0
0
KSZ8893MQL/MQLI
M9999-111705