Turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- Community Forums
- :
- Forums
- :
- Vivado RTL Development
- :
- Implementation
- :
- CORDIC SINCOS

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Mute
- Printer Friendly Page

Highlighted
##

shivanagis

Observer

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

01-04-2017 09:24 PM

6,082 Views

Registered:
09-28-2016

CORDIC SINCOS

Hi all experts.

I want to use the Cordic IP for finding the sin and cosine values. what is the IP setting to use it? I am using Vivado 2014.3. suppose if I am giving angle in radians of 1.507. how to see the sin and cosine value for this by using cordic IP.

Shashidhar

5 Replies

Highlighted
##

prathikm

Moderator

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

01-04-2017 09:35 PM

6,076 Views

Registered:
09-15-2016

Re: CORDIC SINCOS

Hi @shivanagis,

The Design Flow Steps is given in page.37 of this document: https://www.xilinx.com/support/documentation/ip_documentation/cordic/v6_0/pg105-cordic.pdf

For the functional description and vector rotation equation of the CORDIC algorithm please refer page. 16 and 17 respectively of this document: https://www.xilinx.com/support/documentation/ip_documentation/cordic/v6_0/pg105-cordic.pdf

The Fixed-Point CORDIC Algorithm is given here (page 2): https://www.xilinx.com/support/documentation/application_notes/xapp552-cordic-floating-point-operations.pdf

Thanks & Regards,

Prathik

-----------------------------------------------------------------------------------------------

Search for documents/answer records related to your device and tool before posting query on forums.

Search related forums and make sure your query is not repeated.

Please mark the post as an answer "Accept as solution" in case it helps to resolve your query.

Helpful answer -> Give Kudos

-----------------------------------------------------------------------------------------------

Highlighted
##

balkris

Xilinx Employee

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

01-04-2017 10:07 PM

6,061 Views

Registered:
08-01-2008

Re: CORDIC SINCOS

When the Sin and Cos functional configuration is selected, the unit vector is rotated by input angle, , using the CORDIC algorithm. This generates the output vector (Cos( ), Sin( )). . See Input/Output Data Representation for more information about CORDIC binary data formats. An optional coarse rotation module is provided to extend the range of input angle, , to the full circle. For this functional configuration, the coarse rotation module is selected by default, but can be manually deselected. See Advanced Configuration Parameters for more information. When this option is not set, inputs must be constrained to lie in the first quadrant, -Pi/4 to + Pi/4. The compensation scaling module is disabled for the Sin and Cos functional configuration as it is internally pre-scaled to compensate for the CORDIC scale factor

Sin and Cos The input angle, PHASE_IN, is expressed as a fixed-point twos complement number with an integer width of 3 bits (2QN format). The output vector, (X_OUT, Y_OUT), is expressed as a pair of fixed-point twos complement numbers with an integer width of 2 bits (1QN format). In this example the input/output width is set to 10 bits.

PHASE_IN: “0001100100” => 000.1100100 => 0.781

X_OUT: “0010110110” => 00.10110110 => 0.711

Y_OUT: “0010110100” => 00.10110100 => 0.703

Thanks and Regards

Balkrishan

--------------------------------------------------------------------------------------------

Please mark the post as an answer "Accept as solution" in case it helped resolve your query.

Give kudos in case a post in case it guided to the solution.

Balkrishan

--------------------------------------------------------------------------------------------

Please mark the post as an answer "Accept as solution" in case it helped resolve your query.

Give kudos in case a post in case it guided to the solution.

Highlighted
##

shivanagis

Observer

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

01-04-2017 10:55 PM

6,049 Views

Registered:
09-28-2016

Re: CORDIC SINCOS

Hello @balkris

First of of I am thinking you for reply.

Here the output is not in the form of X_OUT and Y_OUT. But its giving only one output of 32-bit. I am giving input as -1.5707="1100110111000000" but output is 11000000000000000000000000000111=c0000007.

Thanks and regards

Shashidhar

Highlighted
##

shivanagis

Observer

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

01-06-2017 09:42 PM

6,003 Views

Registered:
09-28-2016

Re: CORDIC SINCOS

Hello @prathik

Thank you for your valuable reply.

I have done according to that cordic algorithm. here I am giving input as 1.57 radian equivalent 32-bit in hexadecimal but output is 64-bit and i am not able to find cos and sine value. Please help me.

Thanks and regards

Shashidhar

Highlighted
##

markcurry

Scholar

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

01-11-2017 02:43 PM - edited 01-11-2017 02:49 PM

5,932 Views

Registered:
09-16-2009

Re: CORDIC SINCOS

Preliminaries:

1. I know nothing about the Xilinx Cordic module - never used it - so take all this with a grain of salt

2. I like to use the Fixed Point notation given here:Fixed-Point Arithmetic: An Introduction, by Randy Yates

The answer you get look right to me.

IN = -1.5707 - you're looking at -PI/2 as your input. In fixed point format of A( 1, 14 ) the input of "0xcdc0" looks reasonable to me (I didn't do the conversion manually, but it looks about right).

The returned value, looks to me to be in fixed point format of A( 1, 30 ). The value returned value of 0xc000_0007 is right around -1.0 when expressed as a real (some rounding errors can be expected). That would be the SIN( IN ), and looks correct to me.

Does the COS output return zero ( or within a few LSBs of zero )?

Regards,

Mark