MSC8144 Freescale Semiconductor, MSC8144 Datasheet - Page 59

• Manufacturer Part Number: MSC8144
• Description: Quad Core Digital Signal Processor
• Manufacturer: Freescale Semiconductor

Figure 32 shows the RGMII AC timing and multiplexing diagrams.
Freescale Semiconductor
GTX_CLK125 reference clock duty cycle
Notes:
1.
2.
3.
4.
5.
6.
7.
(At Transmitter)
At recommended operating conditions with LV
This implies that PC board design will require clocks to be routed with no additional trace delay
For 10 and 100 Mbps, t
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 t
between.
Duty cycle reference is L
This symbol is used to represent the external GTX_CLK125 and does not follow the original symbol naming convention.
GCR4 should be programmed as 0x00048120.
RXD[8:5][3:0]
RXD[7:4][3:0]
TXD[8:5][3:0]
TXD[7:4][3:0]
Table 48. RGMII with No On-Board Delay AC Timing Specifications (continued)
GTX_CLK
(At PHY)
RX_CLK
(At PHY)
RX_CTL
TX_CLK
TX_CTL
Parameter/Condition
MSC8144 Quad Core Digital Signal Processor Data Sheet, Rev. 1
Figure 32. RGMII AC Timing and Multiplexing s
RGT
Vdd
scales to 400 ns +/- 40 ns and 40 ns +/- 4 ns, respectively.
/2.
RXD[3:0]
TXD[3:0]
RXD[4]
TXD[4]
RXDV
TXEN
TXD[8:5]
TXD[7:4]
RXD[8:5]
RXD[7:4]
RXERR
TXERR
RXD[9]
TXD[9]
DD
of 2.5 V +/- 5%.
t
t
SKEWT
SKEWT
t
RGTH
t
G125H
Symbol
/t
G125
RGT
Min
47
t
RGT
of the lowest speed transitioned
Typ
—
t
t
SKEWR
SKEWR
Max
53
Unit
%
59