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Functional Description
The TC9021/TC9020 is part of a new generation of high performance, host-optimized network interface cards
designed for mission critical systems such as servers and high-end workstations. Offering two gigabits per second of
aggregate bandwidth, the TC9021/TC9020 optimizes performance while minimizing network overhead on the host
system. Compared to leading Fast Ethernet solutions, the TC9021/TC9020 transfers data at less than one tenth of
the host CPU utilization rate.
IEEE 802.3z Gigabit Ethernet MAC
The TC9021/TC9020 implements IEEE 802.3z half duplex functions such as Carrier Extension and Packet Bursting.
In full duplex mode, the TC9021/TC9020 implements both symmetrical and asymmetrical flow control via IEEE
802.3x PAUSE MAC Control frames. PAUSE frames can be automatically generated by the TC9021/TC9020
according to programmable flow control thresholds within the on-chip receive FIFO. The TC9021/TC9020 MAC has
been carefully implemented to ensure full wire speed at 1Gbps with 96-bit transmit and 64-bit receive inter-frame
spacing.
GMII, MII and TBI Interface
The TC9021/TC9020 implements both a GMII and MII interface, which offers a simple, cost-effective migration from
Fast Ethernet networks to high-speed Gigabit Ethernet networks over existing Category 5 cabling. For fiber optics
applications, the TC9021/TC9020 implements an IEEE 802.3z 1000BASE-X Physical Coding Sublayer (PCS). The
PCS includes an 8B10B encoder and decoder, Auto-negotiation, and Ten Bit Interface (TBI). With the industry
standard SERDES devices, the TC9021/TC9020 allows for gigabit optical link connections to the host system.
32/64-bit, 33/66MHz PCI Bus
The only one difference between the TC9021 and the TC9020 is the PCI bus width. The TC9020 can only be used in
32-bit PCI bus and The TC9021can be directly interface to either 32-bit or 64-bit bus. Advanced PCI commands, such
as Write and Invalidate, Read Line, and Read Multiple, are also implemented to further improve system
performance.
Bus Master Dual Channel DMA
The TC9021/TC9020 implements independent scatter/gather DMA engines to support full duplex Gigabit Ethernet
connectivity. These two DMA engines are capable of accessing data on any byte boundary and moving data to and
from discontiguous memory locations. This capability eliminates CPU-intensive data copying. Furthermore, each
DMA engine has been carefully designed to sustain well over 1 gigabit per second of throughput across a PCI bus.
This ensures that the TC9021/TC9020 will not be a bottleneck in high performance data networking applications.
Protocol Offloading
The TC9021/TC9020 also off-loads network protocol tasks from the host CPU. It generates TCP, UDP and IP
checksum values for outgoing frames and verifies the checksum value on incoming frames. Ethernet MAC frame CRC
calculation is also implemented on-chip.
e-mail:service@tmi.com.tw
website:www.tmi.com.tw
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