KSZ8993MI Micrel Inc, KSZ8993MI Datasheet - Page 35

• Manufacturer Part Number: KSZ8993MI
• Description: IC SWITCH 10/100 W/TXRX 128PQFP
• Manufacturer: Micrel Inc

Specifications of KSZ8993MI

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 128-MQFP, 128-PQFP
• Number Of Primary Switch Ports: 3
• Internal Memory Buffer Size: 32
• Operating Supply Voltage (typ): 1.8/2.5/3.3V
• Fiber Support: Yes
• Integrated Led Drivers: Yes
• Phy/transceiver Interface: MII/SNI
• Power Supply Type: Analog/Digital
• Package Type: PQFP
• Data Rate (typ): 10/100Mbps
• Vlan Support: Yes
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Pin Count: 128
• Mounting: Surface Mount
• Jtag Support: No
• Operating Supply Voltage (max): 1.89/3.465V
• Operating Supply Voltage (min): 1.71/3.135V
• Power Dissipation: 800mW
• Supply Current: 0.1/0.19A
• Operating Temperature Classification: Industrial
• Data Rate: 100Mbps
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-2124; KSZ8993MI

Forwarding state:
Upstream Special Tagging Mode
Upstream Special Tagging Mode is designed for spanning tree protocol IGMP snooping and is flexible for use in
other applications. The Upstream Special Tagging Mode, similar to 802.1Q, requires software to change network
drivers to modify/strip/interpret the special tag. This mode is enabled by setting both register 11 bit 0 and register
48 bit 2 to “1”.
The STPID is only seen and used by the port 3 interface, which should be connected to a processor.
The KSZ8993M uses a non-zero “port mask” to bypass the lookup result and override any port setting, regardless
of port states (disable, blocking, listening, learning).
For packets from regular ports (port 1 & port 2) to port 3, the port mask is used to tell the processor which port the
packets were received on, defined as follows:
No port mask values, other than the previous two defined ones, should be received in Upstream Special Tagging
Mode. The egress rules are defined as follows:
Micrel, Inc.
October 2008
Software action:
Port setting:
Software action:
“0001” from port 1
“0010” from port 2
Ingress Packets
Tagged with 0x8100 + TCI
Not tagged.
“transmit enable = 1, receive enable = 1, learning disable = 0”
The processor should program the “Static MAC table” with the entries that it needs to receive
(e.g., BPDU packets). The “overriding” bit should be set so that the switch will forward those
specific packets to the processor. The processor may send packets to the port(s) in this state,
see “Special Tagging Mode” for details. Address learning is enabled on the port in this state.
The processor should program the “Static MAC table” with the entries that it needs to receive
(e.g., BPDU packets). The “overriding” bit should be set so that the switch will forward those
specific packets to the processor. The processor may send packets to the port(s) in this state,
see “Special Tagging Mode” for details. Address learning is enabled on the port in this state.
TPID (tag protocol identifier, 0x8100) + TCI.
Table 8. STPID Egress Rules (Switch Port 3 to Processor)
802.1Q Tag Format
Packets are forwarded and received normally.
Learning is enabled.
Table 7. Upstream Special Tagging Mode Format
Egress Action to Tag Field
- Modify TPID to 0x810 + “port mask”, which indicates source port.
- No change to TCI if VID is not null
- Replace null VID with ingress port VID
- Recalculate CRC
- Insert TPID to 0x810 + “port mask”, which indicates source port
– Insert TCI with ingress port VID
- Recalculate CRC
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STPID (special tag identifier, 0x810 +
4 bit for “port mask”) + TCI
Special Tag Format
M9999-020606
KSZ8993M/ML