KS8995MA-EVAL Micrel Inc, KS8995MA-EVAL Datasheet - Page 45

• Manufacturer Part Number: KS8995MA-EVAL
• Description: BOARD EVAL EXPERIMENT KS8995MA
• Manufacturer: Micrel Inc

Specifications of KS8995MA-EVAL

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 576-1018

Semptember 2008
Address
4
3
2
1
0
Register 5 (0x05): Global Control 3
7
6
5
4
3-2
Name
Flow Control and Back
Pressure fair Mode
Huge Packet Support
Legal Maximum Packet
Size Check Disable
Priority Buffer Reserve
802.1q VLAN Enable
IGMP Snoop Enable on
Switch MII Interface
Enable Direct Mode on
Switch MII Interface
Enable Pre-Tag on
Switch MII Interface
Priority Scheme Select
No Excessive Collision Drop
1, will accept packet sizes up to 1536 bytes (inclusive).
0, 1522 bytes for tagged packets (not including packets
with STPID from CPU to ports 1-4), 1518 bytes for
untagged packets. Any packets larger than the specified
value will be dropped.
1, each output queue is pre-allocated 48 buffers, used
exclusively for high priority packets. It is recommended to
enable this when priority queue feature is turned on.
0, no reserved buffers for high priority packets.
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 enabled. All the IGMP packets will be
forwarded to Switch MII port.
0, IGMP snoop disabled.
1, direct mode on port 5. This is a special mode for the
Switch MII interface. Using preamble before MRXDV to
direct switch to forward packets, bypassing internal look-
up.
0, normal operation.
1, packets forwarded to Switch MII interface will be
pre-tagged with the source port number (preamble
before MRXDV).
0, normal operation.
00 = always deliver high priority packets first.
01 = deliver high/low packets at ratio 10/1.
10 = deliver high/low packets at ratio 5/1.
11 = deliver high/low packets at ratio 2/1.
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 the same
register. 0, the max packet size will be determined by bit 1
of this register.
45
Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Pin PMRXER
strap option.
Pull-down (0):
1518/1522 byte
packets. Pull-up
(1): 1536 byte
packets.
Note: PMRXER
has internal pull-
down.
Pin PMRXD1
strap option. Pull-
down (0): Drop
excessive collision
packets. Pull-up
(1):
Don’t drop
excessive collision
packets. Note:
PMRXD1 has
internal pull down.
M9999-091508
Default
00
0
0
0
0
0
1
0