Programming an FPGA with Verilog looks a great deal like programming. however it isn’t, at least not in the conventional sense. There have been a number of systems that objective to take C code as well as convert it into a hardware description language. one of these, cynth, is easy to utilize as well as offered on GitHub. You will requirement to set up scala as well as a develop system called sbt, if you want to try it.
There are limitations, of course. If you want a preprocessor, you’ll have to run it separately. You can’t utilize worldwide variables, multiplication, floats, as well as numerous other pieces of C. The compiler produces a Verilog data for every C function.
A conventional C program executes one thing each time unless you utilize special methods on a multiprocessor. even then, there is some useful limit to exactly how numerous CPUs you will likely control. An FPGA, on the other hand, enables you to execute things that happen in parallel. For example, think about this:
while (1)
{
out1=ctr1++;
out2=ctr2++;
}
The out1 value is going to modification a bit bit before the value in out2. If you had a lot of these, state as much as out999, the delay might be significant. equivalent Verilog code may look like:
always @(posedge clk)
begin
out1<=ctr1;
ctr1<=ctr1+1;
out2<=ctr2;
ctr2<=ctr2+1;
end
This looks practically the same, however the outputs will modification at the exact same time no matter exactly how numerous there are. What’s much more is that all the other things you can’t see will likewise occur at the exact same time. just like a hardware as well as entrance doesn’t “scan” its inputs, an FPGA processes all of its inputs as well as produces outputs.
In the situation of cynth, each C function produces a Verilog module that has the exact same arguments as the function together with one more disagreement to stand in for the return value, if any. There will likewise be inputs for the system clock, a reset signal, as well as three manage signals. One is an input that allows the processing. There are two outputs. One indicates the function is offered to allow as well as one more indicates a result is available.
The example offered with the code is a Cylon eye pattern that drives four LEDs. There are two outside functions that are produced with pure Verilog. The write_leds function drives the LEDs as well as a sleep function creates a delay.
The C code is a simple function named roving:
while (1)
{
if (dir && c == 8)
dir = 0;
else if (!dir && c == 1)
dir = 1;
if (dir)
c <<= 1;
else
c >>= 1;
write_leds(c);
sleep(1000); // 1s
}
The corresponding Verilog data carry out the exact same function as you can confirm utilizing a Verilog emulator.
If you want to dig into the produced code, you can discover out much more about Verilog with some projects. If C isn’t your thing, you might always try Python.