MPC8541E datasheet(22/84 Pages) FREESCALE

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MPC8541E PowerQUICC™ III Integrated Communications Processor Hardware Specifications, Rev. 4

Freescale Semiconductor

Ethernet: Three-Speed, MII Management

8.2

GMII, MII, TBI, RGMII, and RTBI AC Timing Specifications

The AC timing specifications for GMII, MII, TBI, RGMII, and RTBI are presented in this section.

8.2.1

GMII AC Timing Specifications

This section describes the GMII transmit and receive AC timing specifications.

8.2.2

GMII Transmit AC Timing Specifications

Table 20 provides the GMII transmit AC timing specifications.

Figure 6 shows the GMII transmit AC timing diagram.

Figure 6. GMII Transmit AC Timing Diagram

Table 20. GMII Transmit AC Timing Specifications

At recommended operating conditions with LVDD of 3.3 V ± 5%.

Parameter/Condition

Symbol 1

Min

Typ

Max

Unit

GTX_CLK clock period

tGTX

—8.0

—

GTX_CLK duty cycle

tGTXH/tGTX

—

GMII data TXD[7:0], TX_ER, TX_EN setup time

tGTKHDV

2.5

—

GTX_CLK to GMII data TXD[7:0], TX_ER, TX_EN delay

tGTKHDX

0.5

—

5.0

GTX_CLK data clock rise and fall times

tGTXR

, tGTXR

2,4

——

1.0

Notes:

1. The symbols used for timing specifications herein follow the pattern t(first two letters of functional block)(signal)(state) (reference)(state)

for inputs and t(first two letters of functional block)(reference)(state)(signal)(state) for outputs. For example, tGTKHDV symbolizes GMII

transmit timing (GT) with respect to the tGTX clock reference (K) going to the high state (H) relative to the time date input

signals (D) reaching the valid state (V) to state or setup time. Also, tGTKHDX symbolizes GMII transmit timing (GT) with respect

to the tGTX clock reference (K) going to the high state (H) relative to the time date input signals (D) going invalid (X) or hold

time. Note that, in general, the clock reference symbol representation is based on three letters representing the clock of a

particular functional. For example, the subscript of tGTX represents the GMII(G) transmit (TX) clock. For rise and fall times,

the latter convention is used with the appropriate letter: R (rise) or F (fall).

2. Signal timings are measured at 0.7 V and 1.9 V voltage levels.

3. Guaranteed by characterization.

4. Guaranteed by design.

GTX_CLK

TXD[7:0]

tGTKHDX

tGTX

tGTXH

tGTXR

tGTXF

tGTKHDV

TX_EN

TX_ER

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