Fun with interfacing GHDL
whygee
I have recently written "interesting code" that
is useful, reusable and has useful properties,
so here I want to share my results. They have
all been developed for Linux, Little Endian, 32-bit
and ease the development work or enhance the
capabilities of GHDL. Most use the VHPIDIRECT
to interface with some C code.
The code can be found there : http://ygdes.com/GHDL/
http://ygdes.com/GHDL/ghdl_env/ :
adds a "getenv" function that reads
the requested environment variable and returns an integer
(strings are too complex to pass back from C)
http://ygdes.com/GHDL/clk/ :
generate a "real time clock", which helps slowing
down a simulation. The clock period is given as a
generic in milliseconds, though the system calls
will easily round up this if you're not careful.
It's quite useful if you want to synchronise a
testbench at a few Hz.
http://ygdes.com/GHDL/lfsr4/ :
it's a scalable 4-xor LFSR, from 5 taps to 786,
very handy to have.
http://ygdes.com/GHDL/fb/ :
adds a simple and nicely working interface
to the Linux framebuffer in 32-bit mode (RGBA).
It needs to be enhanced in the future but it's
powerful enough for doing nice pictures like this
demo : http://ygdes.com/~whygee/lissajous.png
Have fun,
yg
--
http://ygdes.com / http://yasep.org