LM3S1621 Datasheet, PDF (345/947 Pages) Texas Instruments – ARM and Thumb are registered trademarks and Cortex is a trademark

Stellaris^® LM3S1621 Microcontroller
Figure 8-2. Example of Ping-Pong μDMA Transaction
µDMA Controller
Primary Structure
SOURCE
DEST
CONTROL
Unused
transfers using BUFFER A
BUFFER A
Peripheral/_{µDMA Interrupt}
Alternate Structure
SOURCE
DEST
CONTROL
Unused
transfers using BUFFER B
BUFFER B
Peripheral/_{µDMA Interrupt}
Primary Structure
SOURCE
DEST
CONTROL
Unused
transfers using BUFFER A
BUFFER A
Peripheral/_{µDMA Interrupt}
Alternate Structure
SOURCE
DEST
CONTROL
Unused
transfers using BUFFER B
BUFFER B
Cortex-M3 Processor
· Process data in BUFFER A
· Reload primary structure
· Process data in BUFFER B
· Reload alternate structure
· Process data in BUFFER B
· Reload alternate structure
8.2.6.5
Memory Scatter-Gather
Memory Scatter-Gather mode is a complex mode used when data must be transferred to or from
varied locations in memory instead of a set of contiguous locations in a memory buffer. For example,
a gather μDMA operation could be used to selectively read the payload of several stored packets
of a communication protocol and store them together in sequence in a memory buffer.
January 21, 2012
345
Texas Instruments-Production Data