Texas Instruments TM4C1294NCPDT - Figure 9-2. Example of Ping-Pong dma Transaction

Figure 9-2. Example of Ping-Pong μDMA Transaction
Alternate Structure
Primary Structure
Primary Structure
Alternate Structure
transfer continues using alternate
BUFFER B
BUFFER A
· Process data in BUFFER A
· Reload primary structure
transfers using BUFFER A
BUFFER A
transfers using BUFFER A
transfers using BUFFER B
transfer continues using alternatetransfer continues using primary
BUFFER B
transfers using BUFFER B
Peripheral/µDMA Interrupt
· Process data in BUFFER B
· Reload alternate structure
· Process data in BUFFER B
· Reload alternate structure
µDMA Controller
Cortex-M4F Processor
Time
Peripheral/µDMA Interrupt
Peripheral/µDMA Interrupt
SOURCE
DEST
CONTROL
Unused
SOURCE
DEST
CONTROL
Unused
SOURCE
DEST
CONTROL
Unused
SOURCE
DEST
CONTROL
Unused
9.2.6.5 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.
June 18, 2014686
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)