mpc8641 Freescale Semiconductor, Inc, mpc8641 Datasheet - Page 40

• Manufacturer Part Number: mpc8641
• Description: Integrated Host Processor Hardware Specifications
• Manufacturer: Freescale Semiconductor, Inc

Ethernet: Enhanced Three-Speed Ethernet (eTSEC), MII Management
At recommended operating conditions with L/TV
Figure 19
40
Clock period duration
Duty cycle for 10BASE-T and 100BASE-TX
Rise time (20%–80%)
Fall time (80%–20%)
Notes:
1. Note that, in general, the clock reference symbol representation for this section is based on the symbols RGT to represent
2. This implies that PC board design will require clocks to be routed such that an additional trace delay of greater than 1.5 ns
3. For 10 and 100 Mbps, t
4. Duty cycle may be stretched/shrunk during speed changes or while transitioning to a received packet's clock domains as long
5. Guaranteed by characterization
6. ±100 ppm tolerance on RX_CLK frequency
RGMII and RTBI timing. For example, the subscript of t
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).
will be added to the associated clock signal.
as the minimum duty cycle is not violated and stretching occurs for no more than three t
between.
(At Transmitter)
shows the RGMII and RTBI AC timing and multiplexing diagrams.
RXD[8:5][3:0]
RXD[7:4][3:0]
TXD[8:5][3:0]
TXD[7:4][3:0]
Parameter/Condition
GTX_CLK
MPC8641 and MPC8641D Integrated Host Processor Hardware Specifications, Rev. 2
(At PHY)
(At PHY)
RX_CTL
RX_CLK
TX_CLK
TX_CTL
3
Figure 19. RGMII and RTBI AC Timing and Multiplexing Diagrams
Table 35. RGMII and RTBI AC Timing Specifications (continued)
RGT
scales to 400 ns ± 40 ns and 40 ns ± 4 ns, respectively.
RXD[3:0]
TXD[3:0]
DD
RXD[4]
TXD[4]
TXEN
RXDV
3, 4
of 2.5 V ± 5%.
RXD[8:5]
RXD[7:4]
TXD[8:5]
TXD[7:4]
RXERR
TXERR
RXD[9]
TXD[9]
t
RGT
RGTH
Symbol
t
t
t
RGT
RGTR
RGTF
represents the TBI (T) receive (RX) clock. Note also that the
/t
5,6
RGT
5
5
1
5
t
t
SKRGT
SKRGT
t
RGTH
Min
7.2
40
—
—
RGT
Typ
8.0
50
t
—
—
of the lowest speed transitioned
RGT
Freescale Semiconductor
t
t
SKRGT
SKRGT
Max
0.75
0.75
8.8
60
Unit
ns
ns
ns
%