Working with Cosine

[Ed Cannady]

I would like to use the COS function to determine which part of a sine wave I am on. What I do not know is what the data is going to look like and how accurate the data will be. Thanks in advance for any and all help.

Best, Ed

[mister_e]

i'll suggest you something else, take a few reading of your signal with the internal adc, store those data into array or internal EPROM and play with. Refering to a table will be much easier and much code efficient. BUT it's my own opinion, probably Melanie or somebody else have a better solution.

[Acetronics2]

Hi,Ed

You'll get -127 to +127 as a result ... so, look at the highest digit to see where you are on your sine ( ascending = 1, descending = 0 ).

But do not forget to convert degrees as here:

Result = COS ( X * 256 / 360 ) ... for X in degrees.
Side = Result.7

Looking also to SIN highest digit will show you the quarter where you are ...

For accuracy ... 7 bits !!!

Alain