![Freescale Semiconductor MCF54455 Reference Manual Download Page 620](http://html1.mh-extra.com/html/freescale-semiconductor/mcf54455/mcf54455_reference-manual_2330541620.webp)
Fast Ethernet Controllers (FEC0 and FEC1)
Freescale Semiconductor
26-2
26.1.2
Block Diagram
shows the block diagram of a single FEC. The FECs are implemented with a combination of
hardware and microcode. The off-chip (Ethernet) interfaces are compliant with industry and IEEE 802.3
standards.
Figure 26-1. FEC
n
Block Diagram
The descriptor controller is a RISC-based controller providing these functions in the FECs:
•
Initialization (those internal registers not initialized by you or hardware)
•
High level control of the DMA channels (initiating DMA transfers)
•
Interpreting buffer descriptors
•
Address recognition for receive frames
•
Random number generation for transmit collision backoff timer
Internal Bus
Control/Status
FIFO
FEC DMA
Descriptor
Controller
MII
Receive
Transmit
Bus
Controller
Controller
(RISC +
microcode)
I/O
PAD
MDO
MDEN
MDI
FIFO
RAM
FEC Bus
FEC
n
_COL
FEC
n
_RXCLK
FEC
n
_RXD
V
1
FEC
n
_TXC
LK
2
FEC
n
_MDC
FEC
n
_MDIO
MII to RMII
MII
FEC
n
_TXD
0
FEC
n
_TXEN
FEC
n
_RXD0
FEC
n
_RXER
FEC
n
_TXD
1
FEC
n
_RXD1
REF_CLK
2
PAR_FEC
Register
RMII
FEC
n
_TXD
[3:2]
FEC
n
_TXER
FEC
n
_RXD[3
:2]
FEC
n
_CRS
MII
7-Wire
RAM
Interface
Registers
Interface
Internal Bus
Crossbar Switch
Master Bus
Notes:
1
FEC
n
_RXDV in RMII mode generates RXDV and CRS.
2
FEC
n
_TXCLK in RMII mode is the reference clock for the RMII; the
RMII supplies the FEC’s receive and transmit clocks depending
upon the assertion of RCR
n
[RMII_10T].
MIB
Counter RAM
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 ...