Datasheet

Micrel, Inc. KS8995MA/FQ
October 2011 48 M9999-102611-3.0
Global Registers (Continued)
Address Name Description Mode Default
Register 2 (0x02): Global Control 0
1 UNH Mode
1, the switch will drop packets with 0x8808 in T/L filed, or DA=01-80-
C2-00-00-01.
0, the switch will drop packets qualified as “flow control” packets.
R/W 0
0 Link Change Age
1, link change from “link” to “no link” will cause fast aging (<800µs) to
age address table faster. After an age cycle is complete, the age logic
will return to normal (300 + 75 seconds ). Note: If any port is
unplugged, all addresses will be automatically aged out.
R/W 0
Address Name Description Mode Default
Register 3 (0x03): Global Control 1
7 Pass All Frames
1, switch all packets including bad ones. Used solely for debugging
purpose. Works in conjunction with sniffer mode.
R/W 0
6 Reserved Reserved. R/W 0
5
IEEE 802.3x Transmit
Flow Control Disable
0, will enable transmit flow control based on AN result.
1, will not enable transmit flow control regardless of AN result.
R/W
Pin PMRXD3
strap option.
Pull-down(0):
Enable Tx
flow control.
Pull-up(1):
Disable Tx/Rx
flow control.
Note:
PMRXD3 has
internal pull-
down.
4
IEEE 802.3x Receive
Flow Control Disable
0, will enable receive flow control based on AN result.
1, will not enable receive flow control regardless of AN result.
Note: Bit 5 and bit 4 default values are controlled by the same pin, but
they can be programmed independently.
R/W
Pin PMRXD3
strap option.
Pull-down (0):
Enable Rx
flow control.
Pull-up (1):
Disable Tx/Rx
flow control.
Note:
PMRXD3 has
internal pull-
down.
3
Frame Length Field
Check
1, will check frame length field in the IEEE packets.
If the actual length does not match, the packet will be dropped (for L/T
<1500) .
R/W 0
2 Aging Enable
1, Enable age function in the chip.
0, Disable aging function.
R/W
Pin LED[5][2]
strap option.
Pull-down (0):
Aging disable
Pull-up (1):
Aging enable.
Note:
LED[5][2] has
internal pull
up.