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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Cordic-based Sine Computer

Enter the sin and cos of the desired angle and the core calculates the angle. Angles beyond 45 degrees just get smaller.

Anyway, the cast is an additional safety net. Now that we have a working design and only now!

Computing sin & cos in hardware with synthesisable Verilog

In contrast, a Verilog designer is forced to deal with low-level representational issues explicitly. To put it mathematically. On the one hand, we can constrain the instances as integer subtypes by specifying the valid integer range at construction time. When writing synthesizable code, a MyHDL designer can use a high-level view for integer operations by using the intbv type, and rely on the underlying two’s complement representation to do the right thing automatically.

One important feature of the convertor is that it handles the details of signed and unsigned representations automatically. Here is my code to compute sine and cosine of the input angle using cordic algorithm:. The two states that we will use are 0an idle state, and 1a state indicating computation is occurring.


On this page, vetilog are mainly interested in the mechanical characteristics of the algorithm and their hardware implications. To see this, first calculate the angles of the vectors in Fig 1 above:.

Email Required, but never shown. To set up a co-simulation, we need to create a Cosimulation object for the Verilog design. On the other hand, we can access their two’s complement representation as a bit vector, for example for slicing or right-shifting.

Using a CORDIC to calculate sines and cosines in an FPGA

The Verilog output is as follows:. Here, we follow the convergent rounding approach to drop any excess bits. For our purposes, it can be shown that. Obviously, MyHDL code intended for synthesis also has to take synthesis-related restrictions into account. Both the sine and the cosine of the input angle will be computed. For more information and background on the algorithm itself, please consult other sources, such as this paper by Ray Andraka.

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. This is the easy part.

Cordic-based Sine Computer Introduction Specification Unit test Algorithm Design Clrdic conversion to Verilog A discussion about some convertor features Taking advantage of the elaboration phase Handling negative numbers Verilog co-simulation Implementation. Coric high-level, algorithmic work, this is much easier.

Unable to figure it out, I am beating my head. O ye simple, understand wisdom: How do we rotate a vector? The dual nature of this class comes in very handy. The next step is to rotate the xv[0] and yv[0] values through the remaining phase angle, ph[0].

You would then have a vector that has been rotated by Such a core generator will be our approach here.


The Cordic equations can be used for a variety of computations. Rotating to zero The next step is to rotate the vefilog and yv[0] values through the remaining phase angle, ph[0]. As the design will perform its calculations in finite precision, there will be rounding errors.

Is there any way to get around this error?

This module computes the sine and cosine of an input angle. Some can ignore the gain. A simple two-dimensional rotation matrix is given by:. You forgot to assign algodithm port direction to angle: It requires only adds, subtracts, and shifts. This means that the code has already been elaborated by the Python interpreter. The convertor has to deal with several potential pitfalls.

These applications would nominally send 1,0 into the algorithm as an input. In this mode the user supplies a X and Y cartesian vector and an angle.

Then, we define the command to start up the Verilog simulator. However, my current simulator Cver tells me that it is. You clear the angle during a reset just like cos, sin, count etc.

We still have several steps remaining. How shall I assign port direction to angle? We also discussed several different types of rounding at that same time. We coreic use this as the basis of our algorithm: In that case just drop it from the port list. By filling in the parameters of the bench function, we can construct an actual test bench that runs a simulation, as follows:.