CS8900 View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS8900

Highly-Integrated ISA Ethernet Controller

Cirrus Logic

CS8900 Datasheet PDF : 132 Pages

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CS8900

Bus Interface Register:

Boot PROM Base Address (Read/Write)

Address 0033h

Address 0032h

Reserved

The most-significant nibble of

Boot PROM base address. The

high-order nibble is reserved.

Address: PacketPage base + 0030h

Address 0031h

Address 0030h

Contains portion of Boot

PROM base address.

The least-significant byte of the

Boot PROM base address.

The lower three bytes (0030h, 0031h, and 0032h) of the Boot PROM Base Address register are used for the

20-bit Boot PROM base address. The upper three nibbles are reserved. See Section 3.6.

After reset, if no EEPROM is found by the CS8900, then the register has the following initial state. If an

EEPROM is found, then the register’s initial value may be set by the EEPROM. See Section 3.3.

XXXX XXXX XXXX 0000 0000 0000 0000 0000

Bus Interface Register:

Boot PROM Address Mask (Read/Write)

Address 0037h

Address 0036h

Reserved

The most-significant nibble of

Boot PROM mask address.

The high-order nibble is

reserved.

Address: PacketPage base + 0034h

Address 0035h

Address 0034h

Contains portion of Boot

PROM mask address. The

lower-order nibble must be

written as 0h.

The least-significant byte of the

Boot PROM mask address.

Must be written as 00h

The Boot PROM address mask register indicates the size of the attached Boot PROM and is limited to 4K bit

increments. The lower 12 bits of the Address Mask are ignored, and should be 000h. The next lowest-order bits

describe the size of the PROM. The upper three nibbles are reserved.

For example:

See Section 3.6.

Size of Boot PROM

4k bits

8k bits

16k bits

XXXX XXXX XXXX 1111 1111 0000

XXXX XXXX XXXX 1111 1110 0000

XXXX XXXX XXXX 1111 1100 0000

0000 0000

After reset, if no EEPROM is found by the CS8900, then the register has the following initial state. If an

EEPROM is found, then the register’s initial value may be set by the EEPROM. See Section 3.3.

XXXX XXXX XXXX 0000 0000 0000 0000 0000

DS150PP2

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