DS643 Datasheet, PDF (167/216 Pages) Xilinx, Inc – Soft Direct Memory Access (SDMA) support

LogiCORE IP Multi-Port Memory Controller (v6.06.a)
This application would require two VFBC PIMs, one for writing the 1080p source and one for the VGA display.
X-Ref Target - Figure 42
1920
Origin Byte
Address
0x1000_0000
1080p Video Frame Stored in External Memory
120
640
360
VGA Read Transfer Region
480
1080
X10924
Figure 42: 1080p Frame to VGA Window
In this example:
• The 1080p source video frame is stored at address 0x10000000. Assuming that each pixel is stored at
32-bits-per-pixel resolution, each pixel is then 4 bytes.
• Because the X Size is stored in number of bytes, the X Size is 1920*4 (7680 bytes). This corresponds to the
hexadecimal number of 0x1E00.
• In this case the X Size and the Stride (also stored in number of bytes) are the same value, 0x1E00.
• The Y Size is stored as the number of lines minus 1, 1080 – 1 (1079) or the hexadecimal number 0x437.
Table 86 shows the command packet for the 1080p source video. This packet could be written to the VFBC during
each source video blank interval, for example:
Table 86: 1080p Source Video Command Packet Data Structure
Command Word 0
31:15
Reserved
14:0
X Size
0x0000_1E00
Command Word 1
31
30:0
Write_NotRead Start Address
0x9000_0000
Command Word 2
31:24
Reserved
23:0
Y Size
0x0000_0437
Command Word 3
31:24
Reserved
23:0
Stride
0x0000_1E00
The VGA display in this example expects to read a 640x480 portion of the 1080p source from the external frame
store starting from the 360^th pixel on the 120^th line. The X Size for the display is 640*4 (2560 bytes). This corresponds
to the hexadecimal number 1400. The Stride remains the same as the 1080p source command, 0x1E00 (or 1920*4)
because the video is stored as a 1080p frame in external memory. The Y Size is 480 – 1 (479) or the hexadecimal
number 0x1DF.
The Start Address for the VGA video display includes the line and pixel offset information and is calculated by
adding (120*1920 + 360)*4 to the origin or base address of the 1080p frame store. This is corresponds to a final start
address of 0x100E_15A0. Table 87 shows the command packet for the VGA video display hardware.
Note: The Write_NotRead bit in Command Word 1 is now zero to denote a read transfer.
DS643 February 22, 2013
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Product Specification