LXT970A 데이터 시트보기 (PDF) - Intel

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LXT970A

Dual-Speed Fast Ethernet Transceiver

Intel 

LXT970A — Dual-Speed Fast Ethernet Transceiver

2.2.4

Hardware Control Interface

The Hardware Control Interface consists of MF<4:0>, CFG <1:0> and FDE input pins. This

interface is used to configure operating characteristics of the LXT970A and to determine the

MDIO Address. When MDDIS is Low, the Hardware Control Interface provides initial values for

the MDIO registers, and then passes control to the MDIO Interface.

When MDDIS is High, the Hardware Control Interface provides continuous control over the

LXT970A. Individual chip addressing allows multiple LXT970A devices to share the MII in either

mode. Table 12, Table 13 and Table 14 show how to set up the desired operating configurations

using the Hardware Control Interface.

.

Table 12. Configuring the LXT970A via Hardware Control

Desired Configuration

Pin Name

Voltage Level

MDIO Registers

Auto-Negotiation Enabled1

Auto-Negotiation Disabled2

MF0

MF0

VMF2, VMF3

VMF1, VMF4

0.12 = 1

0.12 = 0

Normal Operation

(DTE Mode, Nibble Mode, Scrambler Enabled)

MF1

MF2

MF3

VMF1, VMF4

19.13 = 0

19.4 = 0

19.3 = 0

Repeater Mode

MF1

VMF2, VMF3

19.13 = 1

Symbol Mode

MF2

VMF2, VMF3

19.4 = 1

Scrambler Bypass Mode

MF3

VMF2, VMF3

19.3 = 1

1. Refer to Table 13 for Hardware Control Interface functions available when auto-negotiation is enabled.

2. Refer to Table 14 for Hardware Control Interface functions available when auto-negotiation is disabled.

Table 13. LXT970A Operating Configurations / Auto-Negotiation Enabled

Desired

Configuration1,2

MF4

Input Value

CFG1

FDE

MDIO Registers

4.5

4.6

4.7

4.8

Advertise All

VMF1, VMF4

Low

Ignore

1

1

1

1

Advertise 100 HD

VMF2, VMF3

Low

Low

0

0

1

0

Advertise 100 HD/FD

VMF2, VMF3

Low

High

0

0

1

1

Advertise 10 HD

VMF1, VMF4

High

Low

1

0

0

0

Advertise 10 HD/FD

VMF1, VMF4

High

High

1

1

0

0

Advertise 10/100 HD

VMF2, VMF3

High

Low

1

0

1

0

Advertise 10/100 HD/FD

VMF2, VMF3

High

High

1

1

1

1

1. Refer to Table 12 for basic configurations.

2. Refer to Table 14 for Hardware Control Interface functions available when auto-negotiation is disabled.

26

Datasheet

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