LM3S9B81 Datasheet, PDF (243/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Stellaris® LM3S9B81 Microcontroller
Refer to Figure 8-2 for an example showing operation in Ping-Pong mode.
Figure 8-2. Example of Ping-Pong μDMA Transaction
µDMA Controller
Primary Structure
SOURCE
DEST
CONTROL
Unused
transfers using BUFFER A
BUFFER A
Cortex-M3 Processor
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
· 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,
June 29, 2010
243
Texas Instruments-Advance Information