Interconnect
External memory
System initiators
External memory
(NOR/NAND flash)
SMS
VRFB
SDRC
GPMC
SDRC subsystem
Memory subsystem
(SDRAM)
sdrc-019
Public Version
SDRAM Controller (SDRC) Subsystem
www.ti.com
Figure 10-62. SDRC Subsystem Overview
Accessing images stored in external SDRAM in a non-natural order requires an address transaction: the
virtual address of an image is translated into a physical address in the corresponding buffer. Address
translation causes an image to be rotated in 0-, 90-, 180-, or 270-degree views. With multiple views of the
image, the RE can change addresses and issue multiple requests to the SDRC so that a maximum of
consecutive accesses is performed, thus decreasing the number of page-miss penalties. The RE cannot
reorder requests to the SDRAM.
A VRFB context defines the configuration used to access a picture in external SDRAM. For each VRFB
context, a set of registers in the SMS describes:
•
The size of the page (height and width)
•
The picture parameters before rotation (width, height, and pixel format)
•
The rotation angle (0-, 90-, 180-, or 270-degree)
•
The physical base address in external memory
2278
Memory Subsystem
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated
