CS8900A-IQ データシートの表示（PDF） - Cirrus Logic

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CS8900A-IQ

Crystal LAN™ Ethernet Controller

Cirrus Logic 

CS8900A

Crystal LAN™ Ethernet Controller

3.4 Configurations with EEPROM

PacketPage Register Register Descriptions

Address Contents

0020h 0300h

I/O Base Address*

0022h XXXX XXXX Interrupt Number

XXXX X100

0024h XXXX XXXX DMA Channel

XXXX XX11

0026h 0000h

DMA Start of Frame

Offset

0028h X000h

DMA Frame Count

002Ah 0000h

DMA Byte Count

002Ch XXX0 0000h Memory Base Address

0030h XXX0 0000h Boot PROM Base

Address

0034h XXX0 0000h Boot PROM Address

Mask

0102h 0003h

Register 3 - RxCFG

0104h 0005h

Register 5 - RxCTL

0106h 0007h

Register 7 - TxCFG

0108h 0009h

Register 9 - TxCMD

010Ah 000Bh

Register B - BufCFG

010Ch Undefined Reserved

010Eh Undefined Reserved

0110h Undefined Reserved

0112h 00013h

Register 13 - LineCTL

0114h 0015h

Register 15 - SelfCTL

0116h 0017h

Register 17 - BusCTL

0118h 0019h

Register 19 - TestCTL

* I/O base address is unaffected by Software Suspend mode.

Table 4. Default Configuration

EEPROM Type

Size (16-bit words)

‘C46 (non-sequential)

64

‘CS46 (sequential)

64

‘C56 (non-sequential)

128

‘CS56 (sequential)

128

‘C66 (non-sequential)

256

‘CS66 (sequential)

256

Table 5. Supported EEPROM Types

3.4.1 EEPROM Interface

The interface to the EEPROM consists of the

four signals shown in Table 6.

CS8900A Pin

EEPROM

(Pin #)

CS8900A Function

Pin

EECS (Pin 3) EEPROM Chip Select Chip Select

EESK (PIN 4) 1 MHz EEPROM

Serial Clock output

Clock

EEDO (Pin 5) EEPROM Data Out

(data to EEPROM)

Data In

EEDI (Pin 6) EEPROM Data in

(data from EEPROM)

Data Out

Table 6. EEPROM Interface

3.4.2 EEPROM Memory Organization

If an EEPROM is used to store initial configu-

ration information for the CS8900A, the EE-

PROM is organized in one or more blocks of

16-bit words. The first block in EEPROM, re-

ferred to as the Configuration Block, is used to

configure the CS8900A after reset. An exam-

ple of a typical Configuration Block is shown in

Table 7. Additional blocks containing user data

may be stored in the EEPROM. However, the

Configuration Block must always start at ad-

dress 00h and be stored in contiguous memo-

ry locations.

3.4.3 Reset Configuration Block

The first block in EEPROM, referred to as the

Reset Configuration Block, is used to automat-

ically program the CS8900A with an initial con-

figuration after a reset. Additional user data

may also be stored in the EEPROM if space is

available. The additional data are stored as

16-bit words and can occupy any EEPROM

address space beginning immediately after

the end of the Reset Configuration Block up to

address 7Fh, depending on EEPROM size.

This additional data can only be accessed

through software control (refer to Section 3.5

on page 25 for more information on accessing

CIRRUS LOGIC PRODUCT DATASHEET

DS271F4

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