Freescale Semiconductor MCF5329 Reference Manual page 421

15 14
Offset + 0 R TO1
Offset + 2
Offset + 4
Offset + 6
Word Field
Offset + 0 15 Ready. Written by the FEC and you.
R 0 The data buffer associated with this BD is not ready for transmission. You are free to manipulate
1 The data buffer, prepared for transmission by you, has not been transmitted or currently transmits.
Offset + 0 14 Transmit software ownership. This field is reserved for software use. This read/write bit is not modified
TO1 by hardware nor does its value affect hardware.
Offset + 0 13 Wrap. Written by user.
W 0 The next buffer descriptor is found in the consecutive location
1 The next buffer descriptor is found at the location defined in ETDSR.
Offset + 0 12 Transmit software ownership. This field is reserved for use by software. This read/write bit is not
TO2 modified by hardware nor does its value affect hardware.
Offset + 0 11 Last in frame. Written by user.
L 0 The buffer is not the last in the transmit frame
1 The buffer is the last in the transmit frame
Offset + 0 10 Transmit CRC. Written by user (only valid if L is set).
TC 0 End transmission immediately after the last data byte
1 Transmit the CRC sequence after the last data byte
Offset + 0 9 Append bad CRC. Written by user (only valid if L is set).
ABC 0 No effect
1 Transmit the CRC sequence inverted after the last data byte (regardless of TC value)
Offset + 0 8–0 Reserved, must be cleared.
Offset + 2 15–0 Data length, written by user.
Data Data length is the number of octets the FEC should transmit from this BD's data buffer. It is never
Length modified by the FEC.
Offset + 4 15–0 Tx data buffer pointer, bits [31:16]
A[31:16]
Offset + 6 15–0 Tx data buffer pointer, bits [15:0]
A[15:0]
1
The transmit buffer pointer, containing 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.
Freescale Semiconductor
13 12 11 10 9
W TO2 L TC ABC
Tx Data Buffer Pointer - A[31:16]
Tx Data Buffer Pointer - A[15:0]
Figure 19-26. Transmit Buffer Descriptor (TxBD)
Table 19-30. Transmit Buffer Descriptor Field Definitions
this BD or its associated data buffer. The FEC clears this bit after the buffer has been transmitted
or after an error condition is encountered.
You may write no fields of this BD after this bit is set.
MCF5329 Reference Manual, Rev 3
8 7 6 5
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Data Length
Description
1
Fast Ethernet Controller (FEC)
4 3 2 1 0
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19-29