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MAX7219 example and use spi software 5 code lines so easy

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Joined: 13 Nov 2011
Posts: 1
Location: Lima, Peru

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MAX7219 example and use spi software 5 code lines so easy
PostPosted: Sun Nov 13, 2011 12:57 am     Reply with quote

This is an easy program for my power supply, it's really simple, just look at #use spi and void maxsend(){} and that's all. I don't know why people write lots of lines, but this code works with 5 lines including curly braces.

12F683 has no spi hardware so this is useful. Very Happy

I hope you guys like it. Send a message if you want the complete project with proteus.

I'm not good at writing in English. Please don't be mean.

Leave your comments Very Happy Very Happy

#include <12f683.h>
#fuses intrc_io,noput,nowdt,noprotect,nomclr,nobrownout,noieso,nofcmen
#device adc=10
#use delay(clock=4M)
#use fast_io(a)
#use spi(do=pin_a0,clk=pin_a2,bits=16,load_active=1,load=pin_a1,idle=1)
//We have to write this directive, you can add stream and change the pin do, clk, load
//I've used bits 16 'cause max7219 needs 16 bits =)
//The idle is 1, if you put 0, nothing will appear on your displays <- this is really important

int address, data, adqnum, digit[4];      //address, data max's variables
                                 //adqnum for 100 samples
                                 //digit[4] this array keeps 4 digits used in this project
int16 packetmax, result;               //packetmax goes to the max7219
                                 //result keeps the value used to obtain digits
int32 adcvalue=0;                     //this variable keep the adc value read 100 times
float calculus;                        //variable used for (adcvalue * (5/1023))

void maxsend(){                     //routine for max7219 just
   packetmax=make16(address,data);      //make a 16 bit variable address byte high, data byte low
   spi_xfer(packetmax);            //transfer using spi software
}                              //just 5 lines including #use spi. It's really simple right?

void maxsetup(){                     //configure properly
   address=0x09, data=0xff, maxsend();      //it's up to you
   address=0x0a, data=0x01, maxsend();      //just read a minute the datasheet
   address=0x0b, data=0x03, maxsend();      //it's easy and fast.
   address=0x0f, data=0x00, maxsend();
   address=0x0c, data=0x01, maxsend();

void algebra_digits(){
   calculus=adcvalue*0.4887585533;            //500 is the max value, 500=5.00V, but it's float
   result=calculus;                     //transfer the correct value to int result
                                    //if you want to measure a higher voltage just change the float value
                                    //and don't forget using resistors as needed.
                                    //the following 4 lines are used to obtain digits
   digit[0]=result-((result/10)*10);         //units place
   digit[1]=(result/10)-((result/100)*10);      //tens place   
   digit[2]=(result/100)-((result/1000)*100);   //hundreds place
   digit[3]=result/1000;                  //thousands place

void main(){
   setup_comparator(nc_nc_nc_nc);         //no comparator module
   setup_adc(adc_clock_div_16);         //Tad = 4.0us
   setup_adc_ports(an3_analog);         //gpio4 as analog input, u can choose your favorite pin
   set_adc_channel(3);                  //select channel 3 =gpio4
   set_tris_a(0b00011000);               //set port
   delay_ms(1000);                     //wait just for relaxing =), this line is not that important
   maxsetup();                        //

      for(adqnum=1;adqnum<=100;adqnum++){   //collect 100 samples, I usually do this, u can use your favorite method
         adcvalue=adcvalue+read_adc();   //for acquisition.
      algebra_digits();                              //call algebra routine to get each digit
      address=0x01, data=digit[0], maxsend();
      address=0x02, data=digit[1], maxsend();
      address=0x03, data=(digit[2] | 0b10000000), maxsend();   //use OR for adding decimal point
      address=0x04, data=digit[3], maxsend();
      adcvalue=0;                                    //clean adcvalue
Very Happy
Physics works!!!

Joined: 29 May 2014
Posts: 18
Location: Brasil

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PostPosted: Wed Nov 04, 2015 7:28 am     Reply with quote

Hi, i used your code in my project and need use two max7219 and show two diferent value, i need see adc channel 0 and 1.
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