The KS8999 contains eight 10/100 physical layer transceivers, nine MAC (Media Access Control) units with an integrated layer 2 switch.
The device runs in two modes. The first mode is an eight port integrated switch and the second is as a nine port switch with the ninth port available through an MII (Media Independent Interface).
Useful configurations include a stand alone eight port switch as well as a eight port switch with a routing element connected to the extra MII port. The additional port is also useful for a public network interfacing. The KS8999 is designed to reside in an unmanaged design not requiring processor intervention. This is achieved through I/O strapping or EEPROM programming at system reset time.
On the media side, the KS8999 supports 10BaseT, 100BaseTX and 100BaseFX as specified by the IEEE 802.3 committee. Physical signal transmission and reception are enhanced through use of analog circuitry that makes the design more efficient and allows for lower power consumption and smaller chip die size.
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Additional Features

• 9 port (8+1) 10/100 integrated switch with eight physical layer transceivers and one MII/SNI interface
• Advanced Ethernet Switch with internal frame buffer
• 128K Byte of SRAM on chip for frame buffering
• 2.0Gbps high performance memory bandwidth
• Wire speed reception and transmission
• Integrated address look-up engine, supports 1K absolute MAC addresses
• Automatic address learning, address aging and address migration
• Advanced Switch Features
• Supports 802.1p priority and port based priority
• Supports port based VLAN
• Supports 1536 byte frame for VLAN tag
• Supports DiffServ priority, 802.1p based priority or port based priority of broadcast storm protection
• Proven transceiver technology for UTP and fiber operation
• 10BaseT, 100BaseTX and 100BaseFX modes of operation
• Supports for UTP or fiber on all 8-ports
• Indicators for link, activity, full/half-duplex and speed
• Hardware based 10/100, full/half, flow control and auto-negotiation
• Individual port forced modes (full duplex, 100BaseTX) when auto-negotiation is disabled
• Full-duplex IEEE 802.3x flow control
• Half-duplex back pressure flow control
• Supports MDI/MDI-X auto crossover
• External MAC interface (MII or 7-wire) for router applications
• Unmanaged operation via strapping or EEPROM at system reset time (see Reset Reference Circuit section)
• Comprehensive LED support
• Single 2.0V power supply with options for 2.5V and 3.3V I/O
• 900 mA (1.80W) including physical transmit drivers
• Supports both commercial and industrial temperature
• Commercial temperature range: 0°C to +70°C (KS8999)
• Industrial temperature range: –40°C to +85°C (KS8999I)
• Supports lead free products:
• Commercial temperature range: 0°C to +70°C (KSZ8999)
• Industrial temperature range: –40°C to +85°C (KSZ8999I)