2 Phase Sine Generator with pic16F877

[sombre]

hello everybody,
Did someone have experience in 2 Phase Sine Generator with pic16F877
please help!!!! (any book, any datasheet, any url in relation with the topic, or any program)?

[ares]

ne icin yapmayı düşÃ¼nüyorsun koltet motoru mu calıştıracaksın....!!!!!!

[sombre]

Don't understand what you mean!!
Can you speak english?:confused:

[evc]

If you want somebody to help ya, please give some more info! What is the frequency, what is the phase  offset between two sine waves you have to produce, did they have to be synchronous or not and so on ...

[sombre]

If you want somebody to help ya, please give some more info! What is the frequency, what is the phase  offset between two sine waves you have to produce, did they have to be synchronous or not and so on ...

The frequency are : 1HZ, 10HZ, 100Hz, 1KHz, 10KHZ, 100KHZ
I should have the possibility to change frequency in my program, and generate the signal after theses changes.
The two sine waves should have the same frequency, but not the same phase (a difference of Pi/2)
I hope it's enough clear
thanks by advance

[evc]

16F877 @20Mhz -> 200ns per cycle. If you want to perform 100kHz you will have only 10,  max 14 points for period. If its enough for you, then make a table and perform table read upon interrupt on timer. To achieve two sine waves, fastest way is to make table for two periods of the sine wave, and when read it, for seccond output to use offset of Pi/2. Any way you will have to use parallel output (there is no machine time for serial) and R-2R matrix. Another posibility is to use something like AD9832.

[sombre]

thank you very much evc!
But the problem is; how to do to estabilish those tables, is there any mathematic relation that provide the values of the tables?
10x by advance

[sombre]

i forget to mention that i use 16f877 20MHz also

thanks again!

[sombre]

ok! now i've made the two tables, but i've only 1KHz as mximum frequency!
please help!

[evc]

To acheive maximum frequency you must write the module which outputs the table contents on DAC in assembler! Flowchart something like this:
Interrupt on timer -> increment table pointer -> read table -> put the result on PORTD (for example).

[sombre]

thnaks evc i very appreciate!
I use basic proton ide.
i use the PWM to generate the sine wave. (i change the duty...)
any help to have more than 1KHZ?

[sombre]

Thank you guys problem solved!