Using FIFOs in HardwareSoftware Codesign for FPGA based Embedded Systems

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Using FIFOs in Hardware-Software Co-design for
FPGA based Embedded Systems Charlie Ross Wim
Bohm, Colorado State University

Mandelbrot We generate images of the Mandelbrot
set, a fractal in the complex square -2..2,
-2i..2i. Points C in Mandelbrot set make the
loop on the right run indefinitely. The loop
count (i) of points outside the set produces a
pixel with a color, based on a rainbow palette.
If the loop runs for more than 4096 iterations,
it is aborted, and the pixel is colored black.
function Mandelbrot (complex C) int i 0
complex Z C while (magnitude(Z) lt 2) i i
1 Z Z2 C return i
Xilinx VirtexII1000 FPGA
EDK Architecture In software only mode the
MicroBlaze performs the complete computation. In
hardware accelerated mode, the Microblaze
computes fixed point representations of the
complex points C and sends these to the core.
Block Ram
LMB
LMB
MicroBlaze Processor Core
Mandelbrot Core
FSL
OPB Bus
MDM
UART
SVGA
ZBT Memory Framebuffer
SVGA/ZBT The video signals are created by an
OPB core provided by Xilinx. It uses an external
ZBT memory to store the bitmap of the screen.
Debugging MDM and UART OPB peripherals are
present for software debugging purposes and could
be removed from final designs.
Over-sampling A smoother image is created by
averaging the colors of 4 adjacent Mandelbrot
points into one pixel. This requires 4x as much
math, but produces a nicer image.
Hardware acceleration Three versions of a
Mandelbrot core compute 1,2, or 4 points in
parallel. Works well with over-sampling 4
pixels are needed!