IP1000A データシートの表示（PDF） - Unspecified

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IP1000A

Gigabit Ethernet NIC Single Chip

Unspecified 

IP1000A LF

Preliminary Data Sheet

receive frames with the frame patterns in the transmit FIFO. When a matching frame is received (and

also passes the filtering mode set in the Receive-Mode register), a wake event is signaled.

Frame patterns are written to the transmit FIFO in a single “pseudo-packet”. Prior to transferring this

pseudo-packet, the host system should first set the TxReset in the AsicCtrl (to reset the transmit FIFO

pointers and prevent transmission) then prepare a TFD that points to a single data buffer. The buffer

should contain one or more frame patterns placed contiguously. The number of frame patterns is limited

by the transmit FIFO size. The FragLen field in the TFD must exactly equal the sum of the frame pattern

bytes. Also, the host system must set the WordAlign field to ‘x1’ in the TFC0 field of the TFD to prevent

frame word-alignment. Finally, the host system must write the TFD’s address to the TFDListPtr register

to transfer the frame into the transmit FIFO.

The frame patterns in the transmit FIFO specify which bytes in received frames are to be examined.

Each byte in the transmit FIFO specifies a four bit relative offset (from the start of the received frame) in

the most significant nibble and a four bit length indicator in the least significant nibble. Relative offsets

describe the number of bytes of the received frame to skip from the last relevant byte, beginning with

byte 0x00. Relative offsets with a value of 0xF indicate the actual relative offset is larger than 15, and is

specified by the next 8 bit value in the transmit FIFO. Length indicators with a value of 0xF indicate the

actual length indicator is larger than 15, and is specified by the next 8 bit value in the transmit FIFO. If

both the relative offset, and the length indicator are 0xF, the first byte following the relative offset/length

indicator pair is the actual relative offset, and the second following byte is the actual length indicator. A

byte value of 0x00 indicates the end of the pattern for that wake frame. Immediately following the

end-of-pattern is a 4-byte CRC. The calculation used to for the CRC is the same polynomial as the

Ethernet MAC FCS.

An example pseudo-packet (based on the ARP packet example from Appendix A of the “OnNow Network

Device Class Power Management Specification”) which would be loaded into the transmit FIFO of the

IP1000A LF is shown in Figure 2-2.

Figure 2-2 : Example Pseudo Packet

TxFIFO

0xc2

0x71

0xf4

offset and length

indicator pairs

pseudo

packet

0x10

0x00

0xf3

end of pattern

0x19

0x08

CRC to match

0xd7

Table 2-1 deciphers the pseudo packet inFigure 2-2 indicating the relative offset and length indicators

which the IP1000A LF will apply to all receive frames.

Copyright © 2005, IC Plus Corp.

17/75

July 5, 2005

IP1000A LF-DS-R08

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