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STP2002QFP
Fast Ethernet, Parallel Port, SCSI (FEPS) - STP2002QFP
Sun Microsystems,
For TCP packets, hardware support is provided for TCP checksum compu-
tation. On transmit, it is assumed that the entire packet is loaded into the local
FIFO before its transmission begins. The checksum is computed on-the-fly
while the packet is being transferred from the host memory into the local
FIFO. The checksum result is then stuffed into the appropriate field in the
packet, and the transmission of the frame begins. On receive, checksum is
computed on the incoming data stream from the MAC core, and the result is
posted to the device driver as part of the packet status in the descriptor.
5.2.2 Functional Blocks
The Ethernet channel is comprised of five major blocks:
BigMAC core
Management interface (MIF)
Ethernet transmit (ETX)
Ethernet receive (ERX)
Shared Ethernet block (SEB)
5.2.2.1 BigMAC Core
The BigMAC core implements the IEEE 802.3 MAC protocol for 10-/100-
Mbps CSMA/CD networks. It consists of four major functional modules:
Host interface buffer
Implements the programmed I/O interface between the SEB and Big-
MAC core
Transmit MAC (TX_MAC)
- Implements the IEEE 802.3 transmit portion of the protocol
- Implements the slave interface handshake between the ETX and
TX_MAC for frame data transfers
- Performs the synchronization between the system clock domain and
the transmit media clock domain in the transmit data path
Receive MAC (RX_MAC)
- Implements the IEEE 802.3 receive portion of the protocol
- Implements the slave interface handshake between the ERX and
RX_MAC for frame data transfers
- Performs the synchronization between the system clock domain and
the receive media clock domain in the receive data path