HOW TO IMPLEMENET FOLLOWING EQ. IN VHDL

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koolslash

Joined: 24 May 2009
Posts: 26

27 Jun 2009 15:32 ano ang emotional quotient o eq-tagalog version

(NO. of pulses / total pulses) * 255

then round off the result and convert it to binary.

ANY IDEA OR SOLUTION????

barath_87

Joined: 07 Feb 2006
Posts: 171
Helped: 10

27 Jun 2009 15:39 vhdl quotient

Can you tell what actually you are trying to implement instead of a math eqn. because your eqn looks odd.

koolslash

Joined: 24 May 2009
Posts: 26

27 Jun 2009 21:19 vhdl eq

actually i have writen a counter to count number of pulses.
now, i want to:
1. calculate the following:
(no. of pulses counted ÷ total expected pulses) x 255
NOTE: its same like calculating percentage.
2. i have used 255 because it is represented in binary 11111111.
3. this whole equation will give me the pulses percentage from 255.
e.g (20 ÷40) x 255 = .5 x 255 = 127.5
4. now i want to round of this to 127 or 128 any.
5. then convert this result to binary.

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linkfox

Joined: 18 Dec 2007
Posts: 52
Helped: 3

28 Jun 2009 2:07 vhdl calculation of percentage

koolslash wrote:

you can find implementations for fixed point divisions on-line, on FPGA they provided division IP cores;
but they can only return quotient and remainder, but not 0.5 as u want;
so my suggest would be either do a1 = (total expected pulses/255), then (no. of pulses counted/a1), and take the quotient; or a1 = no. of pulses counted * 255, then a1/ total expected pulses.
also you can use 256 instead of 255 to save one division, since u dont require high accuracy.