Sine wave generating from PIC

Hello friends,

To do sinusoidal modulation you need sine wave which can be compared with high frequency carrier(triangular waves). And i was also about to generate Sine modulation so i needed to do this.


      You can generate by calculating sine values at run time also but that is time consuming and keeps your microcontroller busy with calculations only, so I suggest you to make a look up table  and recall the value at run time from there.

      So here is what I have done its a simple task just have a look at the code,....

///////////////////////////////////////////////////////////
#include "pic .h
#include "htc .h"
#define _XTAL_FREQ 4000000

const unsigned char wave[181] ={128,132,137,141,146,150,155,159,163,168,172,176,180,184,188,192,196,200,203,207,210
,214,217,220,223,226,229,232,234,237,239,241,243,245,247,248,250,251,252,253,254,254,
255,255,255,255,255,255,255,255,254,253,252,251,250,248,247,245,243,241,239,237,234,
232,229,226,223,220,217,214,210,207,203,200,196,192,188,184,180,176,172,168,163,
159,155,150,146,141,137,132,128,124,119,115,110,106,101,97,93,88,84,80,76,72,68,64,
60,56,53,49,46,42,39,36,33,30,27,24,22,19,17,15,13,11,9,8,6,5,4,3,2,1,1,0,0,0,0,0,1
,1,2,3,4,5,6,8,9,11,13,15,17,19,22,24,27,30,33,36,39,42,46,49,53,56,60,64,68,72,76,
80,84,88,93,97,101,106,110,115,119,124,128};

int main(void)
{
TRISD = 0x00;
unsigned char i;

for(i=0;i<181 ;i++) {
PORTD = wave[i];
__delay_us(79);
}

return 0;
}
///////////////////////////////////////////////////////////

 But,here instead of using normal DAC to generate sine wave I have here used R-2R ladder(no specific reason).
Here is the schematic.

Here VSM Timer counter is used to measure the frequency generated by R-2R DAC. 


The output of the circuit is as shown below..

if you want to make frequency variable just keep a variable in delay and update it by any key..... 


For more Proteus projects  click here.

Read more ...

Sinusoidal modulation in PIC

Hello Friends,

Many of the readers are asking for sinusoidal modulation with pic microcontrolle. So here is the answer....

1)Read my previous post about sine wave modulation.

2)Now you need  Sine wave of 50Hz to generate reference for modulation.Read this post about generating Sinusoidal waveforms with PIC. (you can generate sine wave from any microcontroller by using this method.)

3)Create a triangle wave either from microcontroller or 555 timer IC.

4)You are done ......





You can see other AVR Projects HERE.

Read more ...

Graphical programming including VHDL with code generation

Hello friends i was always fascinated about programming graphically so we don't need to write any code(that saves your lot energy, don't consider me lazy!!!!).

Here is the answer of

How to do VHDL programming graphically?

step1) Open NI- Multisim

step 2) go to place menu and select "New PLD Sub circuit"

 

step 3) then a PLD wizard will open select "Create empty PLD" and in subsequent steps select the name of circuit and operating voltage of the processor ( it has nothing to do with code generation but only useful for simulation in Multisim)

step 4) click on the PLD setting Button

step 5) you will be asked  for input, output and bi-directional pins in this menu

step 6) now make whatever circuit you want to make(time to  have fun!!!)...

step 7)  Click on PLD topology check

step 8) if there is no error in your topology you can export the VHDL code

step 9) finally your VHDL code is ready to be saved save it whenever you want  and have fun.

step 10)  Go to main circuit and build some circuit around your PLD to simulate

 
 Step 11) Don't forget to leave a comment here.....!!!!

"LET THY BE FREE FROM TEXTUAL PROGRAMMING"

                                                                          -Keyur

Read more ...