Implementation of Cordic Algorithm for FPGA. Based Computers Using Verilog. pani1, ju, a3. If you’ve never worked with a CORDIC algorithm before, the .. Software programmers like to look at for and while loops in Verilog and think of. The CORDIC rotator seeks to reduce the angle to zero by rotating the vector. To compute . See the description of the CORDIC algorithm for details. */ module.

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The resulting transform, Tis shown below:. In the case of those applications, the task is done. This is just fine for the convertor.

Using a CORDIC to calculate sines and cosines in an FPGA

This code is for the first quadrant, but is easily extended to the full circle by first doing a coarse rotation. For now, remember that the global CE strategy requires that nothing alogrithm unless a CE line is true. But as this code is outside a generator function, it doesn’t matter. The dual nature of this class comes in very handy. The two states that we will use are 0an idle state, and 1a state indicating computation is occurring.

O ye simple, understand wisdom: In this way, the rotating vector can be directed to converge on a particular result vector. The only dordic to prevent this bit-width problem associated with a one-size fits all solution is to use a software program, sometimes called a core generator or coregento tailor the CORDIC to a specifically requested precision.

Angles beyond 45 degrees just get smaller. The user can change the number of bits that represent the x,y, and theta values.


Using a CORDIC to calculate sines and cosines in an FPGA

For detailed information, you can review the synthesis report. This algoritmh determines the number of bits used to represent the angle. For example, consider how the look-up table of elementary arctangents is set up in the SineComputer design:. With the underlying two’s complement representation, it works for positive and negative values of y. I am getting this error from days now.

For our purposes, it can be shown that. Moreover, it enables fine-grained range error checking at run-time. From here you can see that this is most definitely a rotation matrix with an amplitude increase associated with it. You can think of this as a series of complex rotation vectors, indexed by ksuch as those are shown in Fig 1.

You clear the angle during a reset just like cos, sin, count etc. Both the sine and the cosine of the input angle will be computed. Not all applications need gain compensation. It veriloh a vpi module that defines the interface between the MyHDL simulator and the Verilog simulator.

Cordic Algorithm using Verilog – Electrical Engineering Stack Exchange

Post as a guest Name. This is one of those rare cases where a for loop makes sense in Verilog. Cordic Algorithm using Verilog Ask Question. Back to project URL https: A simple two-dimensional rotation matrix is algoritum by:. In this mode the user supplies a X and Y cartesian vector and an angle.

On this page, we are mainly interested in the mechanical characteristics of the algorithm and their hardware implications.

The pleasant consequence is that the restrictions of the “convertible subset” apply only to the code inside generator functions, not to any code outside them. Here is my code to compute sine and cosine of the input angle using cordic algorithm: The reason is that the convertible subset is much less restrictive.


The number of stages and the number of bits in each stage can both be defined based upon arguments to the core generator program. The Cosimulation object is then constructed with the command as its verolog parameter, followed vefilog a number of keyword arguments.

That allows you to pick the number of most-significant bits that you need, for the precision you want. Unable to figure it out, I am beating my head. Further, as you may have guessed from Fig 1 above, we can apply a similar rotation going in the opposite direction: Also, the arctangent values tan -i 2 -i can be precomputed and stored in a small look-up table.

The page for rotation on Wikipedia tells us that it is equivalent to left-multiplying by verlog particular matrix: To implement the design, we will use the Cordic algorithm, a very popular algorithm to compute trigonometric functions vrilog hardware.

Rotating to zero The next step is to rotate the xv[0] and yv[0] values through the remaining phase angle, ph[0].

To put it mathematically. In particular, multiplications with a factor 2 -i are simply shift-right operations. Of course, we still need to make sure that the convertor gets it right, which is hard enough. I updated the code as output [