KSZ9031RNX(2012) Ver la hoja de datos (PDF) - Micrel

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KSZ9031RNX
(Rev.:2012)

Gigabit Ethernet Transceiver with RGMII Support

Micrel 

Micrel, Inc.

KSZ9031RNX

Loopback Mode

The KSZ9031RNX supports the following loopback operations to verify analog and/or digital data paths.

• Local (digital) loopback

• Remote (analog) loopback

Local (Digital) Loopback

This loopback mode checks the RGMII transmit and receive data paths between KSZ9031RNX and external MAC, and is

supported for all three speeds (10/100/1000Mbps) at full-duplex.

The loopback data path is shown in Figure 5.

1. RGMII MAC transmits frames to KSZ9031RNX.

2. Frames are wrapped around inside KSZ9031RNX.

3. KSZ9031RNX transmits frames back to RGMII MAC.

Figure 5. Local (Digital) Loopback

The following programming steps and register settings are used for local loopback mode.

For 1000Mbps loopback,

1. Set register 0h,

• Bit [14] = 1

• Bits [6, 13] = 10

• Bit [12] = 0

• Bit [8] = 1

2. Set register 9h,

• Bit [12] = 1

• Bit [11] = 0

// Enable local loopback mode

// Select 1000Mbps speed

// Disable auto-negotiation

// Select full-duplex mode

// Enable master-slave manual configuration

// Select slave configuration (required for loopback mode)

For 10/100Mbps loopback,

1. Set register 0h,

• Bit [14] = 1

• Bits [6, 13] = 00 / 01

• Bit [12] = 0

• Bit [8] = 1

// Enable local loopback mode

// Select 10Mbps/100Mbps speed

// Disable auto-negotiation

// Select full-duplex mode

October 2012

29

M9999-103112-1.0

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