readme

cordic implementation in vhdl&c

cordic.c: reference C model
  To use compile it using gcc cordic.c -o -lm cordic
  Then type cordic and press enter, to get 'how to use it' message
  Follow the instructions
point2bin.c: gives fixed point binary corresponding to a 'decimal real
  number N', such that 0<N<1.0
  Again compile it using gcc point2bin.c -lm -o point2bin
  The type 'point2bin' and press enter to get further instructions
bin2point.c : inversof point2bin

cordic.vhd: VHDL RTL for finding sin/cosine of an angle, theta, such that
  0<= theta <= 90. The design has NOT been tested for out of range theta
cordic_tb.vhd: VHDL testbench for cordic.vhd 

fun_pkg.vhd: Defines some functions which are used by cordic.vhd

The Algorithm takes 14 clock cycles to output the result.
The Inputs to the design are
clk
rstn : active low reset
angle: Angle of which sin/cos is desired, a fixed point number
  Example: if the sin/cos for say 40 Degree is desired, then
  angle = fixed point representation of 40/256 i.e(0.15625)
  fixed point representation may be found corresponding to 0.15625
  by using 'point2bin 15625' which will yeild 00101000000000000000000000000010
  Where point2bin is executable obtained by 'gcc point2bin.c -lm -o point2bin'
  and 15625 is the number following decimal point.
  Another Example:
  Angle = 5 Degrees, = 5/256 = .01953125
  fixed point rep = point2bin 01953125 = 00000101000000000000000000000010 
  The o/p is 32 bit, but the design takes a 25 bit input, so you may axe
  7 msbs from this
angle_valid: This must be put to '1' for at least one clock cycle to 
  start the design. It is edge sensitive. It should not be pulsed again
  before receipt of a corresponding 'ready' signal.For starting new
  calculation, this signal has to be pulsed with pulse widht of at least
  one clock cycles. 

The Outputs from the design are:
 ready: signals that sin/cos value are valid on outputs sinout and cosout