UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
751 of 1269
NXP Semiconductors
UM10503
Chapter 26: LPC43xx Ethernet
The DMA always reads or fetches four DWORDS of the descriptor from system memory
to obtain the buffer and control information as shown in
. When Advanced
timestamp feature support is enabled, TDES0 has additional control bits[6:3] for channel 1
and channel 2. For channel 0, the bits 6:3 are ignored. The bits 6:3 are described in
Fig 75. Transmitter descriptor fields
O
W
N
Status [16:0]
Buffer 1 Address [31:0]
Buffer 2 Address [31:0] or Next Descriptor Address [31:0]
R
E
S
Buffer 2 Byte Count [28:16]
Buffer 1 Byte Count [12:0]
31
0
TDES0
TDES3
TDES2
TDES1
T
T
T
S
Reserved
TDES4
Reserved
TDES5
Transmit Time Stamp Low [31:0]
TDES6
Transmit Time Stamp High [31:0]
TDES7
R
E
S
R
E
S
Ctrl
[30:26]
T
T
S
E
R
E
S
Ctrl
[23:20]