17-50
MCF5282 User’s Manual
MOTOROLA
Buffer Descriptors
Figure 17-28. Transmit Buffer Descriptor (TxBD)
Table 17-37. Transmit Buffer Descriptor Field Definitions
Word
Location
Field Name
Description
0
Bit 15
R
Ready. Written by the FEC and the user.
0 The data buffer associated with this BD is not ready for
transmission. The user is free to manipulate 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.
1 The data buffer, which has been prepared for transmission
by the user, has not been transmitted or is currently being
transmitted. No fields of this BD may be written by the user
once this bit is set.
0
Bit 14
TO1
Transmit software ownership. This field is reserved for software
use. This read/write bit will not be modified by hardware, nor will
its value affect hardware.
0
Bit 13
W
Wrap. Written by user.
0 The next buffer descriptor is found in the consecutive
location
1 The next buffer descriptor is found at the location defined in
ETDSR.
0
BIt 12
TO2
Transmit software ownership. This field is reserved for use by
software. This read/write bit will not be modified by hardware,
nor will its value affect hardware.
0
Bit 11
L
Last in frame. Written by user.
0 The buffer is not the last in the transmit frame.
1 The buffer is the last in the transmit frame.
0
Bit 10
TC
Tx CRC. Written by user (only valid if L = 1).
0 End transmission immediately after the last data byte.
1 Transmit the CRC sequence after the last data byte.
0
Bit 9
ABC
Append bad CRC. Written by user (only valid if L = 1).
0 No effect
1 Transmit the CRC sequence inverted after the last data byte
(regardless of TC value).
0
Bits [8:0]
—
Reserved.
0
2
4
6
Tx Data Buffer Pointer - A[15:0]
Data Length
TC
L
TO2
W
TO1
R
ABC
Tx Data Buffer Pointer - A[31:16]
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Summary of Contents for ColdFire MCF5281
Page 124: ...3 20 MCF5282 User s Manual MOTOROLA EMAC Instruction Set Summary ...
Page 141: ...MOTOROLA Chapter 5 Static RAM SRAM 5 5 SRAM Programming Model ...
Page 142: ...5 6 MCF5282 User s Manual MOTOROLA SRAM Programming Model ...
Page 168: ...6 26 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 186: ...7 18 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 228: ...9 22 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 246: ...10 18 MCF5282 User s Manual MOTOROLA Low Power Wakeup Operation ...
Page 254: ...11 8 MCF5282 User s Manual MOTOROLA Memory Map and Registers ...
Page 264: ...12 10 MCF5282 User s Manual MOTOROLA Chip Select Registers ...
Page 280: ...13 16 MCF5282 User s Manual MOTOROLA Misaligned Operands ...
Page 314: ...14 34 MCF5282 User s Manual MOTOROLA MCF5282 External Signals ...
Page 339: ...MOTOROLA Chapter 15 Synchronous DRAM Controller Module 15 25 SDRAM Example ...
Page 340: ...15 26 MCF5282 User s Manual MOTOROLA SDRAM Example ...
Page 356: ...16 16 MCF5282 User s Manual MOTOROLA DMA Controller Module Functional Description ...
Page 408: ...17 52 MCF5282 User s Manual MOTOROLA Buffer Descriptors ...
Page 446: ...20 24 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 474: ...22 18 MCF5282 User s Manual MOTOROLA Programming Model ...
Page 510: ...23 36 MCF5282 User s Manual MOTOROLA Operation ...
Page 526: ...24 16 MCF5282 User s Manual MOTOROLA I2C Programming Examples ...
Page 672: ...28 12 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 718: ...29 46 MCF5282 User s Manual MOTOROLA Motorola Recommended BDM Pinout ...
Page 750: ...32 8 MCF5282 User s Manual MOTOROLA Ordering Information ...