MSC8144E Reference Manual, Rev. 3
18-30
Freescale
Semiconductor
QUICC Engine™ Subsystem
Table 18-9 lists the RMII signals.
18.7.5 SMII Interface
The Ethernet controller SMII receive and transmit interface complies with the Cisco serial MII
specification. In this mode, the controller supports a MAC-to-PHY or a MAC-to-MAC
connection:
SMII MAC-to-PHY interface. Conveys complete MII information between a 10/100 PHY
and MAC using two signals per port and generates the output
SYNC
signal to allow a
MAC-to-PHY connection. The SMII reference clock generates both transmit and receive
clocks for the MII interface clocks. To configure the Ethernet controller, write a value of
0b10 to MIIGSKCFGR[IFMODE] and select the
SYNC
output signal by writing a 0 to
MIIGSK_SMII_SYNCDIR[SYNC_IN] and a 1 to MIIGSK_SMII_SYNCDIR[SYNC].
The operating mode is determined by the Frequency Control bit
(MIIGSK_CFGR[FRCONT]); the default value 0 selects 100 Mbps operation. For 10
Mbps operation, set the frequency by writing a 1 to MIIGSK_CFGR[FRCONT].
MAC-to-MAC connection. The SMII uses a
SYNC
input signal to support data
synchronization and disables the typical output
SYNC
signal generation. Select this mode
by writing a value of 0b10 to MIIGSK_CFGR[IFMODE] and selecting the
ETHSYNC_IN input by writing a 1 to MIIGSK_SMII_SYNCDIR[SYNC_IN] and a 0 to
MIIGSK_SMII_DYNCDIR[SYNC]. The operating mode is determined by the Frequency
Control bit (MIIGSK_CFGR[FRCONT]); the default value 0 selects 100 Mbps operation.
Table 18-9. RMII Signals
Consortium
Name
I/O
Size
Function
Reference
Clock
TXD[0–1]
O
2
Transmit Data
REF_CLK
TX_EN
O
1
Transmit Enable
Asserted by the MAC sublayer when the first transmit preamble byte
is driven over the RMII. It remains asserted up to the last CRC byte
REF_CLK
MDIO
I/O
1
Management Data I/O
Transfers control signals between the PHY layer and the manger
entity.
MDC
MDC
I
1
Management Data Clock
The MDIO signal clock reference (25 MHz clock).
—
CRS_DV
I
1
Receive Data Valid
Asserted by the PHY layer when the first received preamble byte is
driving over the RMII. It remains asserted f up to the last CRC byte.
REF_CLK
REF_CLK
O
1
Reference Clock
50 MHz synchronous clock reference for receive, transmit, and control
interface.
—
RX_ER
I
1
Receive Error
Asserted by the PHY layer to indicate an error the MAC cannot detect.
If it is asserted during frame reception, it indicates a coding error on
the frame currently transferred on RXD[1–0].
REF_CLK
RXD[0–1]
I
2
Receive Data
REF_CLK
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
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 ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...