Fast Ethernet Controller (FEC)
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
18-52
Freescale Semiconductor
NOTE
After the software driver has set up the buffers for a frame, it should set up
the corresponding BDs. The last step in setting up the BDs for a transmit
frame should be to set the R bit in the first BD for the frame. The driver
should follow that with a write to TDAR which triggers the FEC to poll the
next BD in the ring.
4
Bits [15:0]
A[31:16]
Tx data buffer pointer, bits [31:16]
1
6
Bits [15:0]
A[15:0]
Tx data buffer pointer, bits [15:0].
1
The transmit buffer pointer, which contains the address of the associated data buffer, must always be evenly divisible by 4. The
buffer must reside in memory external to the FEC. This value is never modified by the Ethernet controller.
Table 18-37. Transmit Buffer Descriptor Field Definitions (continued)
Word
Location
Field Name
Description
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60
