COLOR_KEY
MATCH
MATCH
Source element
Destination element
NO
MATCH
No_ Wr
No_ Wr
Write
dma-012
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SDMA Functional Description
NOTE:
The packet size can be a sub-multiple or non sub-multiple of a frame size. If DMA
Packet_Data_Size is aligned on DMA channel block data size boundary, DMA will transfer
the last data in channel block boundary and stop at block boundary for the last packet DMA
request. If the Packet_Data_size is not aligned on the block boundary, the remaining data
smaller than a packet size are transferred using burst or single accesses to complete the
block.
•
DMA Packet_Data_Transfer does not affect DMA channel capabilities in term of packing and bursting.
The Packet synchronization mode is active when
[5] FS =
[18] BS = 1. Then
- if
[24] SEL_SRC_DST_SYNC=0;
[15:0] gives the number of element in
packet and
[31:16] is unused for the packet size.
- if
[24] SEL_SRC_DST_SYNC=1;
[15:0] gives the number of element in
packet and
[31:16] is unused for the packet size.
NOTE:
The maximum transfer size, regardless of the packet size, is always: Block_size =
Number_of_Frame_in_Block x Number_of_Element_in_Frame x Element_Size. If the DMA
channel packet/burst access is across packet boundary, DMA hardware automatically splits
this packing/burst access into multiple smaller accesses, which will be aligned on packet
boundary. Otherwise, the DMA transfers data as usual packing/burst access.
11.4.14 Graphics Acceleration Support
The SDMA supports two graphic acceleration features:
•
Transparent copy
•
Constant fill
Only one of these features can be enabled at any given time through the
register for the
particular logical DMA channel.
The transparent copy feature enables specification of a particular color through the
register, so that when it is recognized in the data from the source, it is not copied to the corresponding
location in the destination, but instead leaves the data in the corresponding location in the destination as it
is.
shows the 2-D graphic transparent color block diagram.
Figure 11-12. 2-D Graphic Transparent Color Block Diagram
The constant fill feature provides the ability to specify a particular color through the
register for every specified location in the destination. In this case, the transfer consists only of writing to
the destination without reading from a source.
2359
SWPU177N – December 2009 – Revised November 2010
SDMA
Copyright © 2009–2010, Texas Instruments Incorporated
