Ethernet Controllers
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
18-33
18.7.5.2 Serial Gigabit Media-Independent Interface (SGMII) Signals
The SGMII is an alternative to the RGMII interface that further reduces the number of pins
required to interconnect the MAC and PHY by using a SerDes 4 interface. It does not support
auto-negotiation. The Ethernet controller SGMII interface uses the UEC ten-bit interface (TBI)
connection internally, which connects to the SerDes block that serializes the transmitted data and
deserializes the received data to/from the SGMII interface.
18.7.5.2.1 SGMII Signals
The SGMII physical interface transmits and receives data using two data signals and a clock
signals to convey frame data and link rate information between a 1000 Mbps PHY and an
Ethernet MAC. The data signals operate at 1.25 Gbaud. Due to the speed of operation, each of
these signals (including the clock signal) is realized as a differential pair thus providing signal
integrity while minimizing system noise. Therefore, each data and clock signal path uses two
physical signal lines (the differential pair).
Table 18-11 lists the SGMII signals.
MDC
I
1
Management Data Clock
The MDIO signal clock reference (25 MHz clock).
—
RX_CLK
I
1
Continuous Receive Reference Clock
125 MHz
—
Table 18-11. SGMII Signals
Signal Name
I/O
Size
Function
Reference
Clock
SRIO_REF_CLK
SRIO_REF_CLK
I
I
2
Reference Clock
125 MHz differential pair.
—
SG1_TX
SG1_TX
O
O
2
Transmit Data 1
Differential pair for Ethernet 1 controller.
SRIO_REF_CLK
SRIO_REF_CLK
SG2_TX
SG2_TX
O
O
2
Transmit Data 2
Differential pair for Ethernet 2 controller.
SRIO_REF_CLK
SRIO_REF_CLK
SG1_RX
SG1_RX
I
I
2
Receive Data 1
Differential pair for Ethernet 1 controller.
SRIO_REF_CLK
SRIO_REF_CLK
SG2_RX
SG2_RX
I
I
2
Receive Data 2
Differential pair for Ethernet 2 controller.
SRIO_REF_CLK
SRIO_REF_CLK
MDIO
I/O
1
Management Data I/O
Transfers control signals between the PHY layer and the
manager entity.
MDC
MDC
I
1
Management Data Clock
The MDIO signal clock reference (25 MHz clock).
—
Table 18-10. RGMII Signals (Continued)
Consortium
Name
I/O
Size
Function
Reference
Clock
Summary of Contents for MSC8144E
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Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
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Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...