Implementation of Cordic Algorithm for FPGA. Based Computers Using Verilog. pani1, ju, a3. 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. Tags: verilog code for cordic algorithm verilog code for vector verilog code for .. specific device designations, other words log Abstract.. code in the example.

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This is one of those rare cases where a for loop makes sense in Verilog.

Back to project URL https: This is of course simulator-specific. This option gives a result in a single clock cycle at the expense of very deep logic levels.

The interface of the module looks as follows: For pipelined options, this is the number of stages. Cordic-based Sine Computer Introduction Specification Unit test Algorithm Design Automatic conversion to Verilog A discussion about some convertor features Taking advantage of the elaboration phase Handling negative numbers Verilog co-simulation Implementation. We will use this as the basis of our algorithm:. Note how this single-line lookup is expanded into a case statement in the Verilog output.

### Computing sin & cos in hardware with synthesisable Verilog

What we now have is an algorithm that is possible to implement in hardware, but is still equivalent to the original algorithm. Here, we follow the convergent rounding approach to drop any excess bits. In MyHDL, a single type does it all – the intbv class. The first three are 32 bits wide, since they are storing fixed-point numbers as described above.

### Cordic Algorithm using Verilog – Electrical Engineering Stack Exchange

Then also calculate and normalize by their their lengths. This is just fine for the convertor. For example, consider how the look-up table of elementary arctangents is set up in the SineComputer design:. Of course, this transform is not a true rotation matrix. But again, these restrictions vrrilog apply to the code inside generator functions, because only that code is actually converted.

HDL loops on the other hand repeat the instruction in space on the chip by creating multiple copies of the same logic, all of which will be executed in parallel. However, my current simulator Cver tells me that it is.

## Computing sin & cos in hardware with synthesisable Verilog

One would therefore expect a similar feature in other HDLs. The algorkthm arguments make the link between signal names declared in the Verilog test bench stub and signals in the MyHDL code. The fundamental problem is that Verilog uses an unsigned interpretation by default, which is the opposite from what you should do to get the naturally expected results.

To implement the design, we will use the Cordic algorithm, a very popular algorithm to compute trigonometric functions in hardware.

## Using a CORDIC to calculate sines and cosines in an FPGA

Otherwise, Verilog will interprete all operands in a mixed expression as unsigned. We may want to use the test bench for designs with different characteristics; therefore, the error margin is made a parameter. With the underlying two’s complement representation, it works for positive and negative values of y. The Cordic equations can be used for a variety of computations.

The Cordic algorithm can be implemented in many ways, with various characteristics and advantages.

For our purposes, it can be shown that. When the signal names in MyHDL and A,gorithm are identical we can use a little trick and simply pass the local namespace dictionary locals to the constructor.

The internal number variables are represented by intbv instances. Also, the arctangent values tan -i 2 -i can be precomputed and stored in a small look-up table. We will use this as the basis of our algorithm: By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

To compute the cos and sin of the angle, set the inputs as follows: