Texas Instruments TM4C1294NCPDT User Manual

Figure 20-7. RX DMA Operation Flow
(Re-)Fetch next
descriptor
No
Own bit set?
Yes
Yes
Stop RxDMAStart RxDMA Start
No
RxDMA suspended
Yes
Frame data
available?
Wait for frame dataWrite data to buffer(s)
Yes
Yes
Fetch next descriptor
Yes
No
Frame transfer
complete?
No
Set descriptor error
Yes
Time stamp
present?
No
Close RDES0 as last
descriptor
Write time stamp to
RDES6& RDES7
No
Yes
Close RDES0 as
intermediate descriptor
Frame transfer
complete?
No
Flush disabled ?
No
Flush the
remaining frame
Yes
Yes
No
No
No
Yes
Yes
Poll demand/
new frame available
No
Yes
No
Own bit set
for next desc?
Flush
disabled?
A
A
Start = 0
Start = 0
Error
Condition?
Error
Condition?
Error
Condition?
Error
Condition?
Error
Condition?
Receive Descriptor Acquisition
The Receive Engine always attempts to acquire an extra descriptor in anticipation of an incoming
frame. Descriptor acquisition is attempted if any of the following conditions is satisfied:
1431June 18, 2014
Texas Instruments-Production Data
Tiva
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TM4C1294NCPDT Microcontroller

Texas Instruments TM4C1294NCPDT Specifications

General

Brand	Texas Instruments
Model	TM4C1294NCPDT
Category	Microcontrollers
Language	English