MPC8541CPXAJD View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

MPC8541CPXAJD

PowerQUICC™ III Integrated Communications Processor Hardware Specification

Freescale Semiconductor 

Ethernet: Three-Speed, MII Management

8.2.5 RGMII and RTBI AC Timing Specifications

Table 26 presents the RGMII and RTBI AC timing specifications.

Table 26. RGMII and RTBI AC Timing Specifications

At recommended operating conditions with LVDD of 2.5 V ± 5%.

Parameter/Condition

Symbol 1

Min

Typ

Max

Unit

Data to clock output skew (at transmitter)

tSKRGT5

–500

0

500

ps

Data to clock input skew (at receiver) 2

tSKRGT

1.0

—

2.8

ns

Clock cycle duration 3

tRGT6

7.2

8.0

8.8

ns

Duty cycle for 1000Base-T 4

tRGTH/tRGT6

45

50

55

%

Duty cycle for 10BASE-T and 100BASE-TX 3

tRGTH/tRGT6

40

50

60

%

Rise and fall times

tRGTR6,7, tRGTF6,7

—

—

0.75

ns

Notes:

1. Note that, in general, the clock reference symbol representation for this section is based on the symbols RGT to represent

RGMII and RTBI timing. For example, the subscript of tRGT represents the TBI (T) receive (RX) clock. Note also that the

notation for rise (R) and fall (F) times follows the clock symbol that is being represented. For symbols representing skews,

the subscript is skew (SK) followed by the clock that is being skewed (RGT).

2. The RGMII specification requires that PC board designer add 1.5 ns or greater in trace delay to the RX_CLK in order to

meet this specification. However, as stated above, this device functions with only 1.0 ns of delay.

3. For 10 and 100 Mbps, tRGT scales to 400 ns ± 40 ns and 40 ns ± 4 ns, respectively.

4. Duty cycle may be stretched/shrunk during speed changes or while transitioning to a received packet's clock domains as

long as the minimum duty cycle is not violated and stretching occurs for no more than three tRGT of the lowest speed

transitioned between.

5. Guaranteed by characterization.

6. Guaranteed by design.

7. Signal timings are measured at 0.5 and 2.0 V voltage levels.

MPC8541E PowerQUICC™ III Integrated Communications Processor Hardware Specification, Rev. 4.2

Freescale Semiconductor

29

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