LAN89218 datasheet(91/148 Pages) MICROCHIP

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DS60001255B-page 91

LAN89218

5.3.17

WORD_SWAP—WORD SWAP CONTROL

This register controls how words from the host data bus are mapped to the CSRs and Data FIFOs inside the

LAN89218. The LAN89218 always sends data from the Transmit Data FIFO to the network so that the low order

word is sent first, and always receives data from the network to the Receive Data FIFO so that the low order word

is received first.

Offset:

98h

Size:

32 bits

Bits

Description

Type

Default

31:0

Word Swap. This field only has significance if the device is operated in 16-bit

mode. In 32-bit mode, D[31:15] is always mapped to the high order word and

D[15:0] is always mapped to the low order word. In 16-bit mode, if this field is

set to 00000000h, or anything except 0xFFFFFFFFh, the LAN89218 maps

words with address bit A[1]=1 to the high order words of the CSRs and Data

FIFOs, and words with address bit A[1]=0 to the low order words of the CSRs

and Data FIFOs. If this field is set to 0xFFFFFFFFh, the LAN89218 maps

words with address bit A[1]=1 to the low order words of the CSRs and Data

FIFOs, and words with address bit A[1]=0 to the high order words of the

CSRs and Data FIFOs.

Note:

Refer to Section 3.7.1 for additional information.

Note:

Word swap is used in conjunction with the mixed endian function-

ality to determine the final byte ordering. Refer to Section 3.7.4 for

more information.

R/W

NASR

00000000h

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