![Texas Instruments SimpleLink Ethernet MSP432E401Y Скачать руководство пользователя страница 902](http://html1.mh-extra.com/html/texas-instruments/simplelink-ethernet-msp432e401y/simplelink-ethernet-msp432e401y_technical-reference-manual_1095578902.webp)
No
Yes
No
Error Condition?
OWN bit
set?
Error
Condition?
Error
Condition?
Error
Condition?
Start
Start Tx DMA
Stop Tx DMA
A
(Re-)fetch next descriptor
Yes
No
Tx DMA suspended
St
a
rt
=
0
A
Poll demand
No
Transfer data from
buffer(s)
Yes
Yes
Frame xfer
complete?
Wait for Tx status
Timestamp
present?
No
Yes
Write timestamp to
TDES6 and TDES7
Write status word to
TDES0
No
Yes
Yes
Close intermediate
decriptor
No
Functional Description
902
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
Figure 15-7. TX DMA Default Operation Using Descriptors
15.3.3.6.2 TX DMA OSF Mode Operation
While in the RUN state, the transmit process can simultaneously acquire two frames without closing the
Status descriptor of the first if the OSF bit of the EMACDMAOPMODE register is set. As the transmit
process finishes transferring the first frame, it immediately polls the transmit descriptor list for the second
frame. If the second frame is valid, the transmit process transfers this frame before writing the first frame's
status information.