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Fast Ethernet Controller (FEC)
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
18-5
18.4.2
User Initialization (Prior to Asserting ECR[ETHER_EN])
The user needs to initialize portions the FEC prior to setting the ECR[ETHER_EN] bit. The exact values
depend on the particular application. The sequence is not important.
Ethernet MAC registers requiring initialization are defined in
FEC FIFO/DMA registers that require initialization are defined in
.
Table 18-1. ECR[ETHER_EN] De-Assertion Effect on FEC
Register/Machine
Reset Value
XMIT block
Transmission is aborted (bad CRC
appended)
RECV block
Receive activity is aborted
DMA block
All DMA activity is terminated
RDAR
Cleared
TDAR
Cleared
Descriptor Controller block
Halt operation
Table 18-2. User Initialization (Before ECR[ETHER_EN])
Description
Initialize EIMR
Clear EIR (write 0xFFFF_FFFF)
TFWR (optional)
IALR / IAUR
GAUR / GALR
PALR / PAUR
OPD (only needed for full duplex flow control)
RCR
TCR
MSCR (optional)
Clear MIB_RAM (locations 0x1200-0x12FC)
Table 18-3. FEC User Initialization (Before ECR[ETHER_EN])
Description
Initialize FRSR (optional)
Initialize EMRBR
Initialize ERDSR
Initialize ETDSR
Initialize (Empty) Transmit Descriptor ring
Initialize (Empty) Receive Descriptor ring
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an
order
from
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International
Trade
Commission,
BGA-packaged
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States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60