UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
744 of 1269
NXP Semiconductors
UM10503
Chapter 26: LPC43xx Ethernet
Fig 73. TxDMA operation in OSF mode
Previous frame
status available
Start TxDMA
(Re-)fetch next
descriptor
Write status word to
prev. frame’s TDES0
Transfer data from
buffer(s)
(AHB)
error?
Own
bit set?
(AHB)
error?
Frame xfer
complete?
Time stamp
present?
(AHB)
error?
Write time stamp to
TDES2 & TDES3
for previous frame
(AHB)
error?
Stop TxDMA
No
Yes
No
Yes
No
Start
Yes
Close intermediate
descriptor
No
No
Wait for previous
frame’s Tx status
Second
frame?
Yes
Yes
No
Yes
Yes
Write time stamp to
TDES2 & TDES3
for previous frame
(AHB)
error?
(AHB)
error?
Yes
Time stamp
present?
Yes
Write status word to
prev. frame’s TDES0
TxDMA suspended
Yes
No
Yes
No
No
Poll
demand
No
No