Technical information

1-6
AIC-6915 Ethernet LAN Controller Programmer’s Manual
Modules
The AIC-6915 contains the following major modules:
■
PCI
- Controls access to the PCI bus and contains PCI-specific registers.
■
BusAccessControl
- Arbitrates master accesses to the PCI bus from internal
modules, and accesses the FIFO from the PCI side.
■
SlaveAccess -
Drives the REGBUS to access the internal modules when AIC-6915 is
accessed from the PCI bus.
■
General Registers
- Contains general control and status registers, timers, and
interrupt control. These registers are located throughout the AIC-6915.
■
Memory Port
- Controls accesses to external EEPROM, FLASH, or other devices.
■
Serial EPROM
- Controls interface to the serial EPROM.
■
TxDMA
- Manages reading of the current frame being DMA-transferred for
transmit, as well as transmit descriptor lists.
■
TxFrame
- Manages the current frame being transmitted, reading the frame from the
FIFO.
■
RxDMA
- Manages writing of the current frame being DMA-transferred for receive,
as well as the receive descriptor lists.
■
RxFrame
- Manages the current frame being received, writing the frame to the FIFO.
■
Station Address
- Compares the address of incoming frames with the stored
addresses and/or hash table bits, and signals the
RxFrame
module if the addresses
do not match.
■
TCP Checksum
- Two TCP checksum modules are implemented, one for receive and
one for transmit. The Receive TCP checksum module sums all relevant fields and
compares them with the checksum value in the frame. The Transmit TCP checksum
computes the checksum and places it in the FIFO.
■
Wakeup
- Looks for frames matching a predefined pattern and asserts the
PME_
signal to wake up the system if one is found.
■
Completion
- Records the current address for writing completion descriptors and
stores the upper 32-bits of the descriptor’s address.
■
Statistics
- Counts various events from MAC, receive, and transmit.
■
Synchronizer
- Synchronizes receive data and control to the transmit clock.
■
MAC
- The MAC layer defined in the Ethernet specification manages many of the
details in transmitting and receiving frames.
■
8 KByte SRAM
- Dual-port SRAM used for storing transmit and receive data.
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