MPC8378E datasheet(23/128 Pages) FREESCALE

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MPC8378E PowerQUICC II Pro Processor Hardware Specifications, Rev. 8

Freescale Semiconductor

Ethernet: Enhanced Three-Speed Ethernet (eTSEC)

This section provides the AC and DC electrical characteristics for the enhanced three-speed Ethernet

controller.

8.1

SGMII Interface Electrical Characteristics

Each SGMII port features a 4-wire AC-coupled serial link from the dedicated SerDes1 interface of the

MPC8378E as shown in Figure 7, where CTX is the external (on board) AC-coupled capacitor. Each output

pin of the SerDes transmitter differential pair features 50-

Ω output impedance. Each input of the SerDes

receiver differential pair features 50-

Ω on-die termination to SGND_SRDSn (xcorevss). The reference

circuit of the SerDes transmitter and receiver is shown in Figure 65.

When an eTSEC port is configured to operate in SGMII mode, the parallel interface’s output signals of

this eTSEC port can be left floating. Also, when operating in SGMII mode, the eTSEC EC_GTX_CLK125

clock is not required for this port. Instead, the SerDes reference clock is required on L1_SD_REF_CLK

and L1_SD_REF_CLK pins.

Figure 7. 4-Wire AC-Coupled SGMII Serial Link Connection Example

8.2

Enhanced Three-Speed Ethernet Controller (eTSEC)

(10/100/1000 Mbps)—SGMII/MII/RGMII/RTBI/RMII DC Electrical

Characteristics

The electrical characteristics specified here apply to serial gigabit media independent interface (SGMII),

media independent interface (MII), reduced gigabit media independent interface (RGMII), reduced ten-bit

interface (RTBI), reduced media independent interface (RMII) signals, management data input/output

(MDIO) and management data clock (MDC).

SGMII SerDes

Interface

Transmitter

SD_TX

SD_RX

SD_TX

SD_RX

Receiver

CTX

SD_RX

Receiver

Transmitter

SD_TX

CTX

MPC8378E Datasheet(PDF) 23 Page - Freescale Semiconductor, Inc