Mathematics and remainder for PLL MC145158

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  1. - 18th August 2005, 06:56 #1
    Darrel Taylor's Avatar
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    Well, nevermind, I got it figured out anyway.

    Give this a try.
    Code:
    <font color="#000000"><b>Freq1      </b><font color="#008000"><b>VAR WORD
</b></font><b>Freq2      </b><font color="#008000"><b>VAR WORD

</b></font><b>N          </b><font color="#008000"><b>VAR WORD
</b></font><b>A          </b><font color="#008000"><b>VAR WORD
</b></font><b>Remainder  </b><font color="#008000"><b>VAR WORD


</b></font><font color="#0000FF"><b><i>; --- Frequency must be split into 2 variables ---
</i></b></font><b>Freq1 </b>= <b>4336   </b><font color="#0000FF"><b><i>; 433687.5
</i></b></font><b>Freq2 </b>= <b>875
</b><font color="#008000"><b>GOSUB </b></font><b>PLL_Calc

</b><font color="#008000"><b>STOP

</b></font><b>PLL_Calc</b>:
    <b>N </b>= (<b>5018 </b>- <b>Freq1</b>)     
    <font color="#008000"><b>IF </b></font><b>Freq2 </b>&gt; <b>0 </b><font 

color="#008000"><b>THEN          
        </b></font><b>A </b>= <b>1000 </b>- <b>Freq2   
        N </b>= <b>N </b>- <b>1      
    </b><font color="#008000"><b>ELSE                       
        </b></font><b>A </b>= <b>0              
    </b><font color="#008000"><b>ENDIF                      
    </b></font><b>N </b>= <b>N </b>* <b>8          
    A </b>= <b>A </b>* <b>8          

    N </b>= <b>N </b>+ (<b>A</b>/<b>1000</b>)       
    <b>A </b>= <b>A </b>- (<b>A</b>/<b>1000</b>*<b>1000</b>)  
        
    <b>N </b>= <b>N</b>*<b>10                   
    N </b>= <font color="#008000"><b>DIV32 </b></font><b>64                   
    Remainder </b>= <b>R2                     
    Remainder </b>= <b>Remainder </b>* <b>10000      
    Remainder </b>= <font color="#008000"><b>DIV32 </b></font><b>64               
    
    A </b>= <b>A </b>* <b>10000              
    A </b>= <font color="#008000"><b>DIV32 </b></font><b>64                   
    
    A </b>= <b>A </b>+ <b>Remainder
    A </b>= <b>A </b>* <b>64
    A </b>= <font color="#008000"><b>DIV32 </b></font><b>10000
    Remainder </b>= <b>R2
    </b><font color="#008000"><b>IF </b></font><b>Remainder </b>&gt;= <b>5000 </b><font 

color="#008000"><b>THEN </b></font><b>A </b>= <b>A </b>+ <b>1
</b><font color="#008000"><b>RETURN</b></font>
    Last edited by Darrel Taylor; - 18th August 2005 at 07:45.
    DT
  2. - 21st August 2005, 16:24 #2
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    Default not yet OK

    Hi darrel

    I gave it a try but I think there is still a problem

    As I told you it is a part of the C routine, but if i take the remainder from
    :
    Nlong = temp/64000 = 54490000/64000 = 851,40625000
    so the remainder is 0,40625000 and multiply by 64000 divide by 1000
    is giving me the correct A value

    Tis is not the case with your example

    Can you have a look ?, you can try any example of freq (in the range 430000.0 til 440000.0 following my example

    Thanks again
  3. - 21st August 2005, 19:33 #3
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    OOPS, you're right.

    Somehow, in the process of posting it, I lost two 0's in the third DIV32.

    This works better.
    Code:
    <font color="#000000"><b>Freq1      </b><font color="#008000"><b>VAR WORD
</b></font><b>Freq2      </b><font color="#008000"><b>VAR WORD

</b></font><b>N          </b><font color="#008000"><b>VAR WORD
</b></font><b>A          </b><font color="#008000"><b>VAR WORD
</b></font><b>Remainder  </b><font color="#008000"><b>VAR WORD


</b></font><font color="#0000FF"><b><i>; --- Frequency must be split into 2 variables ---
</i></b></font><b>Freq1 </b>= <b>4336   </b><font color="#0000FF"><b><i>; 433687.5
</i></b></font><b>Freq2 </b>= <b>875
</b><font color="#008000"><b>GOSUB </b></font><b>PLL_Calc

</b><font color="#008000"><b>STOP

</b></font><b>PLL_Calc</b>:
    <b>N </b>= (<b>5018 </b>- <b>Freq1</b>)     
    <font color="#008000"><b>IF </b></font><b>Freq2 </b>&gt; <b>0 </b><font 

color="#008000"><b>THEN          
        </b></font><b>A </b>= <b>1000 </b>- <b>Freq2   
        N </b>= <b>N </b>- <b>1      
    </b><font color="#008000"><b>ELSE                       
        </b></font><b>A </b>= <b>0              
    </b><font color="#008000"><b>ENDIF                      
    </b></font><b>N </b>= <b>N </b>* <b>8          
    A </b>= <b>A </b>* <b>8          

    N </b>= <b>N </b>+ (<b>A</b>/<b>1000</b>)       
    <b>A </b>= <b>A </b>- (<b>A</b>/<b>1000</b>*<b>1000</b>)  
        
    <b>N </b>= <b>N</b>*<b>10                   
    N </b>= <font color="#008000"><b>DIV32 </b></font><b>64                   
    Remainder </b>= <b>R2                     
    Remainder </b>= <b>Remainder </b>* <b>10000      
    Remainder </b>= <font color="#008000"><b>DIV32 </b></font><b>64               
    
    A </b>= <b>A </b>* <b>10000              
    A </b>= <font color="#008000"><b>DIV32 </b></font><b>6400       <font color="#0000FF">; <-- Changed, was 64</font>           
    
    A </b>= <b>A </b>+ <b>Remainder
    A </b>= <b>A </b>* <b>64
    A </b>= <font color="#008000"><b>DIV32 </b></font><b>10000
    Remainder </b>= <b>R2
    </b><font color="#008000"><b>IF </b></font><b>Remainder </b>&gt;= <b>5000 </b><font 

color="#008000"><b>THEN </b></font><b>A </b>= <b>A </b>+ <b>1
</b><font color="#008000"><b>RETURN</b></font>
    Last edited by Darrel Taylor; - 21st August 2005 at 23:10.
    DT
  4. - 22nd August 2005, 10:09 #4
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    Default still not Ok

    Sorry Darrel, can you have a look again ?
    In the code A = (A/1000*1000) does not do anything
    So the A counter value is not calculated correctly


    Is it possible to use for freq1 only the 3 first digits
    for freq2 4 digits, it makes more sense and easyer for the serin2 command
    to enter the completer frequency

    433.6875 Mhz so we can split 433 and 6875 into 2 variables

    What you think ?
  5. - 22nd August 2005, 18:13 #5
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    In the code A = (A/1000*1000) does not do anything
    Yes it does! Since PBP only works with integers, dividing by 1000 then multiplying by 1000 will isolate any digits over 1000. With Freq2 only being 3 digits, anything over 1000 gets added to the N value.


    Is it possible to use for freq1 only the 3 first digits for freq2 4 digits
    No. Due to overflow and accuracy problems, Freq2 must only be 3 digits. Since, the numbers are being parsed from ascii text, it shouldn't matter how many digits are in each parameter.

    Here are some sample results of actually running the routine on a PIC16F877.
    Scroll to the right for the PIC results.
    Code:
    <table BORDER="1" CELLSPACING="0" BORDERCOLOR="#000000" CELLPADDING="2" WIDTH="789" height="279">
  <tr>
    <td WIDTH="11%" HEIGHT="23">
      <p></p>
    </td>
    <td WIDTH="9%" HEIGHT="23">
      <p></p>
    </td>
    <td WIDTH="9%" HEIGHT="23">
      <p></p>
    </td>
    <td WIDTH="3%" HEIGHT="213" rowspan="11">
      <p></p>
    </td>
    <td WIDTH="48%" HEIGHT="23" colspan="5">
      <p ALIGN="CENTER">Calculated</td>
    <td WIDTH="2%" HEIGHT="213" rowspan="11">
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>&nbsp;</p>
    </td>
    <td WIDTH="19%" COLSPAN="2" HEIGHT="23">
      <p ALIGN="CENTER">Results from PIC</td>
  </tr>
  <tr>
    <td WIDTH="11%" align="center" ><b>
      <p >Freq</b></td>
    <td WIDTH="9%" align="center" ><b>
      <p >Freq1</b></td>
    <td WIDTH="9%" align="center" ><b>
      <p >Freq2</b></td>
    <td WIDTH="11%" ><b>
      <p >C Result N</b></td>
    <td WIDTH="8%" ><b>
      <p >INT N</font></b></td>
    <td WIDTH="11%" ><b>
      <p >Remainder</font></b></td>
    <td WIDTH="11%" ><b>
      <p >C Result A</font></b></td>
    <td WIDTH="7%" ><b>
      <p >INT A</font></b></td>
    <td WIDTH="10%" align="center" ><b>
      <p >N</font></b></td>
    <td WIDTH="9%" align="center" ><b>
      <p >&nbsp;A</font></b></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">430000.0</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4300</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">0</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">897.5</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">897</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.5</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">32</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">32</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">897</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">32</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">430816.5</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4308</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">165</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">887.29375</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">887</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.29375</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">18.8</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">19</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">887</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">19</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">431123.3</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4311</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">233</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">883.45875</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">883</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.45875</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">29.36</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">29</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">883</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">29</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">432000.0</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4320</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">0</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">872.5</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">872</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.5</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">32</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">32</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">872</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">32</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">432086.1</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4320</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">861</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">871.42375</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">871</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.42375</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">27.12</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">27</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">871</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">27</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">433010.7</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4330</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">107</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">859.86625</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">859</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.86625</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">55.44</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">55</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">859</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">55</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" ><b>
      <p ALIGN="RIGHT">433687.5</font></b></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4336</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">875</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">851.40625</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">851</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.40625</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">26</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">26</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">851</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">26</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">438214.0</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4382</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">140</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">794.825</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">794</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.825</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">52.8</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">53</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">794</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">53</font></td>
  </tr>
  <tr>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">440000.0</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">4400</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">0</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">772.5</font></td>
    <td WIDTH="8%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">772</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">0.5</font></td>
    <td WIDTH="11%" >
      <p ALIGN="RIGHT">32</font></td>
    <td WIDTH="7%" BGCOLOR="#ffff00" >
      <p ALIGN="RIGHT">32</font></td>
    <td WIDTH="10%" >
      <p ALIGN="RIGHT">772</font></td>
    <td WIDTH="9%" >
      <p ALIGN="RIGHT">32</font></td>
  </tr>
</table>
    The only possibility I can see for getting the wrong answer, is that I am rounding the A value in the last line of the routine. You had only requested the integer. If you don't want it to be rounded, simply comment out the ...

    IF Remainder >= 5000 THEN A = A + 1

    If you still get the wrong numbers, let me know.

    <br>
    Last edited by Darrel Taylor; - 22nd August 2005 at 18:21.
    DT
  6. - 23rd August 2005, 21:00 #6
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    Default oeps

    Hi Darrel

    Oeps, I changed A var word to A var byte to save some place
    But as A is only 127, but you use the word space to calculate

    Thanks again, it looks that it works
  7. - 23rd August 2005, 22:30 #7
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    Default

    Just curious where the "R2" comes from?
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