AX88796ALF datasheet(19/68 Pages) ASIX

19 / 68 page

AX88796ALF

3-in-1 Local Bus Fast Ethernet Controller

3.0 Memory and I/O Mapping

There are three memories or I/O mapping used in AX88796A.

EEPROM Memory Mapping

I/O Mapping

Local Memory Mapping

3.1 EEPROM Memory Mapping

The AX88796A supports 16-bit mode 93C56/93C66 serial EEPROM. User can access EEPROM data via I/O

address offset 14H MII/EEPROM Management Register. The EEPROM data will be loaded to internal

memory (0H to 1FH and 400H to 41FH) automatically when hardware reset. It is similar NE2000 PROM store

Ethernet address.

NE2000 driver will read the I/O mode field (offset 1CH and 1EH) of PROM contents to decide the I/O mode

(8-bit mode or 16-bit mode). The I/O mode will be 16-bit mode if the value is 57H, 8-bit mode if 42H.

AX88796A also supports user defined PROM 1CH and 1EH value by EEDO pin if no programmed EEPROM

on board. User can pull-down 10K-ohm at EEDO pin to set 57H to the offset 1CH and 1EH of PROM. It will

be 42H if no connection at EEDO pin.

An example as below,

Addr

D15

05H

00H

0000 0n00

32H

10H

76H

54H

BAH

98H

TAB - 10

EEPROM data format example

Start bit

OP code

Address

Data

(Ref. EEPROM datasheet)

A7 ~ A0

D15 ~ D0

AX88796A auto load timing format

The word_2 to word_4 will map to PROM of 6 bytes

Ethernet address.

Auto load 5 words (including

address 0H self) from EEPROM

and store to PROM area.

The word_1 bit[2] “n “ will effect PROM

address 1CH, 1EH value when software

read this area.

n = 0 : PROM address 1CH, 1EH will be

forced to 57H

n = 1 : PROM address 1CH, 1EH will be

forced to 42H

AX88796ALF 数据表(PDF) 19 Page - ASIX Electronics Corporation

AX88796ALF 数据表(HTML) 19 Page - ASIX Electronics Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

数据表下载