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Fast Ethernet Controllers (FEC0 and FEC1)
Freescale Semiconductor
26-20
15–12
Reserved, must be cleared.
11
RMII_ECHO
RMII Echo. Enables RMII echo mode. RMII 2-bit receive data is processed through the RMII receive logic to the
FEC and also routes through the RMII’s transmit logic to become RMII 2-bit transmit data out.
0 Normal operation.
1 RMII echo mode enabled.
Note:
When RMII_ECHO is set, proper operation is guaranteed only when RMII_MODE = 1, RMII_LOOP = 0 and
LOOP = 0.
10
RMII_LOOP
RMII loopback. Enables RMII loopback mode. Causes the MII transmit outputs from the Ethernet controller to loop
back to the Ethernet controllers’s MII receive inputs through the RMII transmit/receive logic.
0 Normal operation.
1 RMII loopback mode enabled.
Note:
When RMII_LOOP is set, proper operation is guaranteed only when RMII_MODE = 1, RMII_ECHO = 0,
LOOP = 0, and TCR
n
[FDEN] = 1.
9
RMII_10T
RMII 10-Base T. Enables 10Mbps mode of the RMII. Determines the clock frequency of the clock source to the
FEC logic to support 10/100Mbps operations.
0 100 Mbps operation. The 50 MHz RMII reference clock on FEC_TXCLK is sent to the RMII, while a divided-by-2
version (25 MHz) is sent to the FEC.
1 10 Mbps operation. The 50 MHz RMII reference clock on FEC_TXCLK is divided by 10 (5 MHz) and sent to the
RMII, while a divided-by-20 version (2.5 MHz) is sent to the FEC.
8
RMII_MODE
RMII Mode. Indicates if the FEC is in RMII or MII/7-wire mode. This is a read-only bit that reflects the status of the
MII_MODE bit AND’d with the PAR_FEC register in the pin multiplexing and control module. See
“FEC Pin Assignment Register (PAR_FEC),”
for more details.
For FEC0: RMII_MODE = RCR0[MII_MODE] &&
(PAR_FEC[2] && PAR_FEC[1])
Eqn. 26-2
For FEC1: RMII_MODE = RCR1[MII_MODE] &&
(PAR_FEC[6] && PAR_FEC[5])
Eqn. 26-3
0 FEC configured for MII or 7-wire mode as indicated by the MII_MODE bit.
1 FEC configured for RMII operation, only if the MII_MODE bit is set.
To summarize the various settings see the below table.
7–6
Reserved, must be cleared.
Table 26-14. RCR
n
Field Descriptions (continued)
Field
Description
PAR_FEC[2:0]
PAR_FEC[6:5]
MII_MODE
RMII_MODE
(
)
Description
000
x
0
GPIO mode
001
x
0
Non-FEC functions
01
x
0
0
7-wire mode
1
1
RMII mode
10
x
x
0
Reserved
110
x
0
Reserved
111
0
0
7-wire mode
1
0
MII mode
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...